I Did Caffeine Analysis: The Unexpected Truth!
ฝัง
- เผยแพร่เมื่อ 2 มิ.ย. 2024
- Definitely some surprises in this one for me! I suspect this is a topic that I'm not yet done with, so very interested to hear your thoughts or suggestions for future tests!
Related videos:
Caffeine Explained: • Caffeine: Explained
Wired Coffee Support: • James Hoffmann Answers...
Timestamps:
0:00 Intro
0:53 How the analyser works
2:39 Test 1 Filter vs. Espresso
3:59 Test 2 Cumulative Extraction
7:53 Test 3 Contact / Steep Time
9:17 Test 4 Instant Coffee
13:28 Test 5 Light vs Dark roast
16:42 A Note On Caffeine Variance in Different Coffees
18:09 Wrap Up
Links:
Patreon: / jameshoffmann
Limited Edition Merch: geni.us/TensHundredsThousands
My Books:
How to Make The Best Coffee At Home: geni.us/howtomakethebestcoffee
The World Atlas of Coffee: geni.us/atlasofcoffee
The World Atlas of Coffee Audiobook: bit.ly/worldatlasofcoffeeaudio
The Best of Jimseven: geni.us/bestofjimseven
Find me here:
Instagram: / jimseven
Twitter: / jimseven
Things I use and like:
My video kit*: kit.co/jimseven/video-making-...
My current studio coffee kit*: kit.co/jimseven/studio-coffee...
The kitchen set shelving is by Studio Hausen*: bit.ly/studiohausen (they gave me a 10% discount code to share with you which is RGNNV1D)
My glasses: bit.ly/boldlondon
My hair product of choice: geni.us/forthehair
*Affiliate links - บันเทิง
![เกิดใหม่ทั้งทีก็เป็นสไลม์ไปซะแล้ว ซีซั่น 3 - ตอนที่ 57 [ซับไทย]](http://i.ytimg.com/vi/pNhft3YZFRE/mqdefault.jpg)
I'm a PhD analytical chemist with a very serious caffeine-measuring (LC/MS) system sitting right here. If you really want to run enough samples to be able to get reliable variance data on the caffeine content of different coffees, this is what you need. An autosampler. Happy to collaborate and run all the samples you'd like for free. Love the channel and the content!
I wanna be part of that research!
What kind of LCMS are you using?
I’m upvoting this collaboration!
Yes I was just thinking of something serious like liquid chromatography system😂
As a fellow chemist I vouch for this method! Excited to see results from a highly selective and sensitive instrument!
I would have been curious to see numbers for Decaf coffees. I wonder if they achieve the reductions they claim. Great content as always!
I have a feeling they do. The caffeine levels are regulated in the EU and in the USA, and at least in the EU a company can get in trouble for not having the caffeine levels they promised.
I live in the EU and the regulations here are particularly strict. I can drink unlimited decaf coffee at night without any influence on my sleeping. I'm very sensitive - even just a cup of black tea can ruin my night rest. Milk chocolate doesn't, so a few servings of milk choclate is the 'threshold' for not noticing any effects.
I would also like to compare the different decaffeination processes
Yes this would be awesome!
Agreed I would love to see the caffiene amounts for various types of decaf, and various roasters. I love my "Good Night Moon" light roasted decaf. But how late at night can I drink it without it affecting my sleep?
He's actually said in a q&a that he's working on that video!😊 It's a very ambitious plan tho so hard to say when the video will be out:)
I'd love to see exactly how much caffine decaf has in it as well as how coffee compares to different types of tea. Awesome video though!!
I heard a report of a recent report the other day that decaf coffee varies widely in it´s caffeine content; from the claimed 2% of the usual content to almost 50% in some "brands(?)". So I´d also love to see some results of decaf testing if you´ve time on your coffee break Braumeister Hoffman
I would love to see the Caffine Content of cold brew vs. hot brew Tea's.
I've been told cold brew contains less caffine and I'd love to see data on that.
I know it's a coffee channel, but I would like to see tea tested as well.
So my studied opinion (addicted to coffee for 45 years) that longer brew times = more efficient caffeine extraction- is correct?
What I'd really like to see is the difference for various methods using the same coffee, and especially for something like espresso vs. moka or cold brew.
And French Press!
This
me too, I make 8 cups of cold brew starting with 1.75 cups of course grounds, which is a bit more concentrated than most, and way more concentrated than most instructions (most people probably make it stronger than instructions but im probably still in the upper quintile). his analysis of water volume made me wonder if maybe mine is not as high in caffeine as I suspected because though my bean % is higher, my water % is lower, and perhaps negating some of my extra beans. so, for example, would a half gallon of cold brew made with 2 cups of coffee have double the caffeine as if it were made with 1 cup, or less than that because the extraction is less complete. of course then Id want to know the effects of water temperature and brewing time and fridge V counter... its endless, I'm glad he bought the $2,500 device, not me, lol.
As a biochemist, I am incredibly impressed by the scientific rigor of your experiments! I love how you explain your thought processes and demystify the scientific process using an example everyone loves--coffee
Really? What in particular aspect are you referring to?
I was thinking the same thing! Something like this would make a great introductory analytical chemistry lab.
While I understand why it wouldn't be included in the video, it would be great if he included the testing details in the experiment. I'm not interested in the equipment and process (James knows way more about that than almost anyone) but the number of times the tests were run and the variance. Perhaps he could add to the base of the chart the number of times the test was performed and add error bars to the data points.
As a fellow biochemist, I too love James' scientific rigor in his experimental videos. This is why I subscribe to his content.
Microbiologist here (my undergrad was biochem if that counts for anything 😂), I was also pleasantly surprised by the rigor shown. Sure, the results could’ve been presented with error bars and a full methods section, but overall thought he struck a good balance to keep the information digestible
Wonder if the cold brew strength thing holds true for caffeine, or if the cold water (if doing it that way) changes this
That's a very interesting question. On one hand it shouldn't from the pure solubility standpoint (as time replaces heat when dissolving) but the sharp heating and specific physical effects of heating might unlock some more difficult to extract parts of the ground bean. I would be intrigued to see results.🙂
We definitely need the answers for this
@@mortisCZ It's also a bit interesting as shouldn't caffeine sublimate a bit with hot verses not at all with cold?
Yes! from what i have experienced it does seem to be much stronger, the fact that it usually has to sit in a fridge (usually overnight for me) might be the reason for that though.
My heart rate definitely says that cold brew has higher caffeine rates.
Hi, chef here. At 7:50 you speculate that the lag in caffeine extraction in espresso compared to filter might be due to contact time. My speculation, for what it is worth, is that the slower initial caffeine extraction is due to the abundance of sugar, oil and starch in the mixture. As you see the initial espresso pour out of the machine, you can see it has a lot of fat, starch and sugar mixed with the water. All of these things interfere with the power of water to act as a solvent. Once the fat, sugar and starch have been washed out of the coffee mass, the water passing through starts to become more dilute, and thus has more power to dissolve the caffeine, which is water soluble. You can notice the same phenomenon if you try to cook something in pure water, vs trying to cook the same thing in a starchy, sugary, oily solution. It takes much longer to cook in the latter.
That is so damn interesting!!
Thank you for the comment. 😊
Yeah that makes sense from a scientific perspective too. Caffeine isn’t soluble in fat so if the more fat soluble contents filter out first then there’s less of a medium for caffeine to filter out (although my hypothesis is that the fats get filtered out more in the later stages of brewing, which leads to my second point)
Every different substance has a different amount of solubility in water, in the beginning of the brew those chemicals in coffee that have a greater solubility than caffeine gets filtered out first. The waters gonna be very saturated here so caffeine has less of chance of making it out when water wants to grab onto easier molecules, and when most of those have washed away there’s more room for caffeine to hitch a ride.
Beautiful! I've never been concerned about how much caffeine in dark roast...I love it because of it's smell and flavor. I've been making coffee for 65 years. Started at 9 years old on a wood-burning stove at 4:30 every morning to make coffee for my Father who had to drive 50 to 100 miles to work, depending on which job he was doing.
I'd like to hear more comparisons of brew methods: moka pot vs. pour over vs. aero press vs. french press, etc. etc. This is a whole new domain of coffee study. Thanks for bringing it to us, James!
Came here to say this for the Moka pot! I think the aero press exposure time test kind of covered most immersion brew styles.
A web of differences would be what solidifies the insights after all, no absolutes in coffee!
Yes yes yes!!! I switch between 4 brew methods as well as 2 or 3 different coffees. I tend 2 prefer an espresso or moka first thing followed by a 250ml cup from my Clever Dripper. Thank you for your comment and letting me share.
Cold brew! 12hr? 24hr? Room temp? Refrigerated?
Was going to write the same thing.
Oh my god the questions I've been asked about once a week in my 10 years as a barista and was never able to confidently answer have been answered.
Eternal gratitude for this 💞
Yes, but all the phone calls I now need to make explaining how wrong I was….
Spectacular! Thank for the effort! Not only it provides information that may be very valuable to someone, but simply as an example of logic, process, dedication - invaluable!
My two favorite things: Data Science & Coffee. I am looking forward to seeing more experiments!
As someone with no scientific background, I am really impressed with the rigour of your hair care routine. The shape and volume are without equal on this platform or anywhere else. Great work James!
Thank you for normalizing the ratio of scientific to "not-so-scientific" comments. It WAS getting real serious in here.
Caffeine keeps you awake, but that hair keeps you mesmerized
I'd be interested to see how caffeine concentration varies at different fast food locations (McDonalds, Starbucks, etc.). Could also give a good excuse to measure how much coffee extraction happens on average at each location.
why? o-O
That's like testing which public bathroom has the best toilet paper
@@herpderp4078 McDonalds is my third best option for coffee locally. And it's often my only if I'm getting coffee in the afternoon.
They use high quality beans, all be it dark roasted, they have high end equipment, and they are well trained. Mc Cafe is worth visiting in New Zealand more than many bakeries or chain cafes. Milk is steamed properly and not too hot, the espresso has the right key ingredients so it tastes good. Sure, it's a pretty generic flavour profile, but what else would you expect? They have to appeal to everybody.
My preference is for my tiny cafe at the front of a Japanese restaurant which does specialty style coffee, but they close at 2pm, and sometimes my caffeine cravings do not stop at 2pm.
I don't know if other McDonalds have the McCafe quality that NZ does, but in NZ the standard coffee drink is espresso and it's available everywhere, so McDonalds had to invest a few years ago into a good cafe product to have a chance of competing on the market.
@@nomiguda A lot of the really harsh comments towards McDonalds tends to come from Americans, because as I've discovered in my trips there, McDonalds in the USA is notably worse than it is internationally. McDonalds coffee in Canada, for me, rivals most middle-end coffee shops that I've visited. It wont beat a super high quality cafe, but it's good coffee. I've gotten McDonalds coffee in the USA - it's quite bad. (and fwiw I've had the same experience with their food in USA McDonalds vs international. Non American McDonalds seems to have higher quality across the board).
Well that, and hipsters who hate McDonalds because it makes them sound enlightened.
@@Roswend in Dublin these days both mcdonalds breakfast and coffee are absolutely disgusting. made a mistake of going there a week ago. the mcmuffin was super sad, the hash brown had black mold inside and the coffee tasted like someone threw up in the cup.
I'd love to see more analysis including moka pots, j bc I know way more people who have one at home than espresso machines. Granted this was when I lived in Costa Rica where that's more the culture, but still. I use my moka pots most days and despite their ubiquity I haven't found that much data on them; most of it focuses on filter, espresso, or cold brew in my (albeit limited) experience
James, thank you for your time. One would think this type of research would have been conducted already with a large varieties of coffees and parameters, but apparently not. This is solidly beneficial to your views! Thank you
As someone who has to be careful around caffeine intake, it would be great to see some tests done on decaf beans.
What I’ve already read online has mixed results on what amount of caffeine is “left over” after being processed
oh, yes please! I need the truth on this
YES!
I completely agree! James, please do a decaf test. Specifically, could you test coffee that uses the Swiss Water Process? (Marley Simmer Down, Peets, Van Houtte...)
I believe decaffeination is supposed to be about 99 or 98% effective, swiss water decaf process might be a bit less effective, but more like 95%.
Oh, this information is SO needed!!! I suspect many decaf beans would be far less decaf than what we would like...
I know this isn't a tea channel, but I think it would be super interesting to compare the amount of caffeine you've found in coffee with the amount present in a few tea styles (green, black, etc). I feel like there's a general sense that coffee has more caffeine, but I've definitely heard anecdotally that green tea can be comparably strong. Given the sorts of counter-intuitive things you've found in this video, it would be nice to get some more solid data on the question! :)
That's weird. I've always heard black tea has more than green and coffee has more than black tea
I had similar thoughts. My understanding was that while the actual tea leaves have more caffeine than coffee beans, they also hold on to more so a cup of tea has less caffeine than a cup of coffee.
I was about to write the same comment. What about PG Tips!?!
The difference is that in tea there is Theine, which is practically the same compound as caffeine, but in tea there is also tannin, which delays the absorption of theine from the gastrointestinal tract, so tea does not work as quickly and strongly as the caffeine contained in coffee, but it works for a longer period of time
Well, James did buy that analyser, so he could do it!
The measure of a Real Man is weather he will admit to his mistakes. Bravo James
James, this is among my most favorite of your pieces. Laudable science, entertaining, and informative. You are killing it.
And loved the insert at 6:53 in the lab coat. Great production
So im doing a masters in analytical chemistry, so this is super interesting. analysing the amount of chemical x in y is something that we do/think about on a daily basis. I first have to say I have no idea what the "Extraction %" is getting at, both in chemical terms as in normal laymans terms, but I have some educated guesses. Also when I dove into the subject I kinda nerded out a bit, so if something is not clear, please tell me!
1, the caffeine amount: coffee is just above 1% caffeine by weight (1.01 to 1.19%) (Belay et al. Food Chemistry, 2008; Barone & Roberts. Food. Chem. Toxicol. 2002). so your 18 in would be roughly 180 mg of caffeine, so i think the device is pretty accurate for such a small thing that can be used by anyone outside of a lab.
2, the caffeine extraction: There is a couple of things at play here. First its the total liquid you are extracting with. Second its the pressure of the liquid. Since you are doing a liquid extraction, how much of what goes into your water is determined by the solubility mostly. Caffeine is very solubile in water (67 grams / 100 mL at 100 C, and 18 grams / 100 mL at 80 C according to wikipedia). So at the start the solubility is the highest and decreases when you go down. if you brew 38 grams out, with lets say 30 mL water (im just making these numbers up) the max solubility would be 20.1 grams. while this seems very high, you have to think about all the other compounds which are even more solubily in water that fight for the extraction. i am very not surprised your espresso content is lower. all the different compounds are fighting for water, and while caffeine is alright, it does not have amazing solubility. Other compounds are extracted before caffeine.
You say your variable is only contact time, but I think your main variable is water used. you are using 10X the amount of water! that has such a big effect on the total extraction.
3, contact time. While this is somewhat important, this is nowhere near as important as the water used. in this test you also use a lot of water, so your caffeine is extracted quickly. I would like to see you run this kind of test with an espresso machine where you pull the shot longer (you might have to lower your pressures somewhat which might effect your total extraction, but id like to see it)
4. the instant coffee I agree with your points!
5. The changes with roasting coffee: I found this amazing book that you might want to have a look at, its called Espresso Coffee, the science of quality 2nd ed, by Andrea Illy and Rinantonio Viani (2005). They go deep into the chemical changes during roasting (and a whole lot more for the whole coffee process!). I assume again here you did the aeropress extraction, so I dissagree with your assesment that its easier to extract is, thus the caffeine content is higher. As i've shown above, and you have shown with your extraction times, the caffeine is already extracted easily into the coffee. Your contact area should be the same, since you grind them to the same size. Yes its might be slightly more porous in the dark roasted one, but I dont htink that will have a big effect on the extractability. I think its because you lose more water during the longer roast, your caffeine is just more concentrated in the darker roast.
6. So McCusker (Jour. Anal. Toxicol. 2003) did research into caffeine contents of specialty coffee's. They found as big of a swing from 58 mg to 259 mg per dose (they dont specify what that amount was, they say "The caffeine dose of brewed specialty coffee's is shown for a "medium" sized coffee", which i think is stupid. But this gives you an idea what the swing can be.
I hope this is somewhat helpfull, and i'd be happy to help with anymore questions!
Thank you man!
As a Mathematician and Physicist (having done a few courses in Physical Chemistry and Analytical Chemistry), i was really hoping for a comment like yours. Could you nerd out some more? I hope James sees/reads your comment, as I am curious about his answer.
'Extraction' in terms of coffee refers to extraction yield based on total dissolved solids (TDS). What's interesting here is that despite using less water, extraction yield/TDS correlates somewhat consistently over the course of the brew, but caffeine does not - it's less about the total extraction, and more about the rate of caffeine extraction being far lower compared to the rate of yield in espresso.
Great comment, good luck with your masters :)
This is very consistent with what I have heard about basic decaffeination techniques - that caffeine is extracted easily in low concentrations in water, therefore a higher amount of colder water with extract a great deal of caffeine and not much else.
I'm not an analytical chemist - I'm a different type of chemist - but I can add some thoughts.
Solvation is (possibly surprisingly) complex for a start. Solutes don't just stick to the water molecules, they also interact with themselves in what are not infrequently complex equilibria. This can lead to aggregation and potentially to precipitation, but it also influences how they interact with water in turn. So it's reasonable to ask things like 'what's the rate of solvation for each different compound present?' or 'how fast does each thing come back out of solution?' or 'how fast do aggregates form?' (and which aggregates? In what distributions?) among other things.
Entropy and enthalpy are also of critical importance. The caffeine, among other compounds, is already going to be interacting with other things in the coffee (pre solvation). How much energy does it take to break those interactions? How much can you get back from forming new ones in solution? What were the strength of the interactions in solution that you had to break to make the new ones? But equally you're likely to get an entropy increase upon solvation, so how does this weigh up against the net change of the various interactions?
Pressure certainly has an effect on reactions (including solvation) as well. Often comes up in topics like Le Chatelier's principle with gases.
To double up a bit on some of the things Hugo has already gone over, I'll reiterate that amount of water is important too. But also the amount of water present at any one point in time is also important really. Overall everything is effectively competing for solvation and you've got a horrifically nightmarish mess of complex dynamic equilibria.
Oh, I see I found the smart people section of the comments.
After years of watching these videos, I had a good chuckle when James said “I happen to have some coffee right here!”
*Dasha Nekrasova Voice*
"Coffee? heard of it..."
James is at least 37% coffee
I'm glad I found this channel! I wasn't even looking for a coffee-themed channel, it was in my suggestions.
I started my journey about five years ago, simply to give my girlfriend a better coffee. She ended up believing that Nespresso and Keurig were perfect (simply because she puts sugar and milk in her coffees), and I kept grinding my own beans and moving on to a pour over for myself. I've never thought about technique until recently, and here come your videos!
Subscribed, and thanks for doing this!
James. I love your videos. I really think that quality is better than quantity, and your videos help me and everybody to understand coffee nuances and to improve our daily experience overall. For me, using data to explain is the cherry on top of the cake. Very nice!
I'd love to see these experiments with decaf! As someone who can't have a ton of caffeine, but enjoys coffee, I'd love insights into what methods for brewing decaf and what types of decaf coffee produce the least caffeine while still tasting good!
this!!
THIS THIS THIS!!
YES!
Yes please
THIS!
Another vote for decaf research. I wanna know what I’m getting into when I don’t want to mess up my sleep!
Decaf is not coffee, so does not belong in a coffee discussion.
@@einfelder8262Explain how it is not coffee. 🙄
@@elsagrace3893 If you like that stuff it would be impossible to explain. For a person who likes real coffee, no need to explain :)
@@einfelder8262 Being so pompous is a very ungraceful aesthetic.
@@mikewilson7307 So stop being pompous then, and keep your opinion to yourself. You weren't asked.
Thank you so much for making this and being so thoughtful. I have been wondering a lot of the questions you answered!
This was amazing a a pure joy to watch. The most facinating discovery was the light vs dark roast variance. This goes against all legacy knowledge on the subject and provides so much value.
Often, when I want caffeine as the main goal (e.g. driving), I'm getting drinks at gas stations, starbucks, mcdonalds, etc. It would be interesting to see just how much caffeine is actually in some of these "off the shelf" drinks: starbucks canned coffee drinks, frappaccinos, mcdonalds coffee, gas station coffee. Plenty of options for an off the wall video there
I've done the same in the past. If I remember correctly, many canned coffee drinks do actually have the caffeine content printed on them ✌️
Good idea. All "drive thru" caffeine levels would be very helpful for drivers.
Just as a side note - for drivers: if you're drowsy and need a hit, don't hit the coffee - drink a litre of water. Especially if you're accustomed to coffee, it will do more to keep you awake than an espresso. I was told this by a barista when I stopped at a coffee shop to get a drink for the road, I did as I was told and was not disappointed, and it always works for me.
@@guss77 any reason behind it?
@@coffeeeater first of all, most of us are often dehydrated - especially after a long drive - and the first symptom of dehydration is inability to concentrate and dozing. This is often confused for sleepiness - which is what caffeine prevents, but dehydration is cured best by drinking water (and not sweetened drinks that increase dehydration). Secondly, but as importantly, it's hard to doze off when you're bladder is full...
Brew temp vs. caffeine extraction would be interesting. Cold brew seems to have as much as hot coffee but, of course, brew time is usually much, much longer.
Agree - more about the effect of temperature would be amazing
I would love to know this as well.
Yes please test the caffeine level in cold brew!
Would be really interesting to plot pH vs caffeine extraction as well, as this could affect the relative solubility of caffeine
I lived in Italy for 2 years, Germany 3 years, and spent time all thru Europe drinking coffee all the time. And while I really love drinking espresso, it never gave me jump start up for the morning. I had to drink filter coffee for the morning. But, afternoon and evening, I would go to espresso. So I can affirm your testing outcomes.
I concur with that. In my case, a 10-gram Moka coffee gives me more "punch" than a 16-gram espresso, same blend (different grinding of course). There is something in espresso that slows down or dampens the absorption of caffeine, and I think it's tannins, as in black tea.
I agree with his "contact Time" theory of extraction. I prefer French press, and I definitely get a stronger caffeine response from that vs pour over espresso or even cold brew which is claimed to have more caffeine. I like cold brew for other reasons, but I definitely don't get the same buzz. my father usually makes pour over, and I definitely get a buzz from that, but he uses a LOT more coffee bean, so these results tell us that he could probably get the same effect from less of the grounds that he normally uses if he were to switch to French press. some people don't like waiting for the French press, I generally just do other things, it's only like 10 minutes which would be similar to waiting for a full carafe of pour over anyway.
Thank you for sharing such an insightful video! I've always suspected that pour-over and dark roast coffee have higher caffeine content based on my personal experiences, but your theories have shed a whole new light on why this may be the case. It was truly fascinating to learn more about the science behind it.
I'd be super interested to see a comparisons of teas, including a few green teas. Also, it would be interesting to test a decaf coffee and see if any traces are detectable.
definitely, add hot chocolate to the mix as well
I was wondering how teas would hold up when it comes to caffeine. I know that darker teas (black tea, pu-erh) have more caffeine than lighter teas (white, yellow teas, etc) so I actually wasn't surprised that the lighter roasted coffees had les caffeine; I wonder if a pu-erh will have as much caffeine as, say, an espresso.
@@MicukoFelton I find that standard black teas make me feel more caffeinated than Puerh interestingly. Green and yellow tea significantly less than both, but varying a lot depending on the tea and how it's brewed.
This is good. Do this.
I'd also like to see this. Good white tea, being the youngest buds and leaves of the first harvest, is supposedly the highest in caffeine content. The exception being matcha, which is green tea but you're consuming the entire leaf as fine powder.
This is why we love James's channel. The time, effort, and money, that went into making this video are what sets him apart. Really appreciated the insight you brought with this one. 👍
Nice video. Note: If you brew the pour-over by volume instead of weight (ml scooped in vs g weighed in), the lighter roasts will yield a higher caffeine concentration which is why people believe that the caffeine is roasted out. This is because of the difference in density between the coffees (which you noted around 15:45).
Today is a good day. I've just discovered boutique coffee roasters less than 3km from my home & I've finally caught up with Mr Hoffman's videos.
Veteran Barista turned coffee roaster here. I can't thank you enough for solid, evidence-backed research into these topics, and not just anecdotal hunches- especially since many of us don't have the time or resources to look into these things. The light roast vs. Dark roast one for me for sure because I had been telling people one thing as a Barista, but then had to change my tune as I found out things as a roaster. Coffee can be such a nebulous thing, and so I now think in more gray areas and try to be less presumptuous. It's been a fun, humbling journey. I appreciate your honestly and adventurous attitude and passion for education. That keeps me subbed to this channel. 😊🖤
Have you considered temperature as a variant? Presumably, as the flowrate increases in an espresso extraction, the temperature of the cake also increases; this could partly explain the lag in caffeine extraction. Also, in the Aeropress, you saw a plateau at 2 minutes or so; by then, the temperature is likely to have fallen off a little.
Sorry: ex-molecular biologist, now-pilot (I still want to make that video drinking coffee at the altitude at which it was grown - let me know if you'd like to join me!).
Same thing occured to me - if temperature does play a role, I'd really want to see how caffeinated a coldbrew is
I hope James sees this
My first thoughts with the Aeropress results were that the solution simply reached full extraction equilibrium, there's no more free caffeine to be had. EDIT: So, just boil some grounds for an hour or two, to get a maximum...
@@d00dEEE Exactly. Temperature/ heat can make reactions go faster, but you’re still limited by your starting materials and equilibrium dynamics
I really wanted you to test the new popular cold brew coffee. The one that stays around 14-16 hours in cold water and after filtered. It would of been interesting for me if you covered this kind of coffee in this video as I enjoy making myself a cold brew coffee and I think its pretty interesting to compare the caffeine content with the ones you covered.
This is a wonderful video, from a great channel. Thank you for being thorough in all your videos!
As a phd student I really appreciate this kind of content. Good work James, spreading scientific-like experiments over the internet in a subject many loves. I just would like to point out that you absolutely should get a scientist to give you some notes on your experiments and results, I understand that your message is aimed to be as clear as possible, but for the nerdiest of us, it would be very interesting to see many more graphs, comparisons and statistics. Who knows, maybe you can even publish a paper, why not?! xD
I think James has this wonderful skill in separating the science of coffee from the more subjective, artistic elements, and communicating both effectively in a way that few other people achieve. What sets this channel apart is the way that his videos never tell you the 'best' way to brew coffee, only how best to optimise that brewing for your preferences. Understanding and communicating that distinction is such an important skill in any kind of science communication and James has a real talent for it.
Yep! Helping the world to see that science can be your passion! 🤓
3:15 At the risk of my seeming to be excessively pedantic (which I am)...170 is, in fact, _more_ than 50% higher than 110.
Great video, thank you.
Yes, I immediately noticed that - its called listening rather than hearing(!)
Superb work. Broadly relevant, useful to anybody who might be concerned about (or interested in) caffeine in our favorite brew, technically well-characterized (including limitations), beautifully summarized and clearly presented. Thank you, James!
Super interesting video, and thanks for taking the time to do this! The instant coffee piece in particular was intriguing. Also having lived in New Zealand (my wife is from there) and now back in Canada, it's always been interesting to hear the kiwis argue about espresso vs pour over so that nugget of information is helpful for our debates!
Great tests! Some additional curiosities I have:
1. For light vs dark roasts, I wonder if using the Aeropress immersion test, the light roasts will have a longer tail of increasing caffeine % (since your conjecture is that light roasts are harder to extract caffeine out of).
2. How coldbrew compares, both compared to hot coffee, and the theoretical same-strength iced coffee (by brewing hot coffee on top of ice)
3. Things like Keurigs and NEspresso.
Based on the grocery stores here, it would seem like 90% of people brew using Keurig. How well do Keurig machines extract coffee? I wonder how different is the machines with one top vs. 5 top needles.
I also would love to see a cold brew test. That seems to me to be quite a different process than the others. Also one I drink a lot!
This explains why a filter brew gives me a panic attack but after a Latte I'm all good
Lol 😂, same
Apparently, milk also neutralises the effect of the caffeine. Not sure though.
@@danielquevedo9434 as far as I understood it only buffers the caffeine as your intake is the same but the fat in milk retards the caffeine somewhat. no based idea why though, only speculations on my part are that caffeine is super water-soluble and the fat kind of slows it down therefore and the other would be that fat supposedly slows down your metabolism a little. But nothing more than brainfarts.
@@danielquevedo9434 according to the bullet proof coffee community - think coffee with much fat - this shall attenuate, slow down and elongate the effect of Coffein on your body. This seems to be a good explanation that I nearly get a heart attack after 2 cups of filter coffee or lungos out of our JURA Coffee machine. But I'm fine and alert a full day after 1 liter of french press coffee with 0.3 liters of milk every morning. And no heart attack at all.
@Bork Fork , another thing to keep in mind is that the milk in your latte contains fat, which slows down your stomach's processing capacity essentially, so it makes your absorption of caffeine slower and more gradual. Essentially you'd notice a difference in "alertness" faster with a straight double espresso than you would with a latte containing the same double espresso.
Did not think roast had such a huge effect on caffeine. Was also a bit shocked with the pour over and espresso comparison. Cool tests! Would like to see some data on cold brewing.
I'm not a coffee addict, I came here while searching for instant coffee expresso as a keto coconut oil pick me up. Made a half cup and added the oil while enjoying your in depth findings. Bravo!
James, never stop doing what you do! I feel like everything you create appeals right to my core. Such quality production, pace, topics and just overall vibe. Thanks for being that guy, we need more people who are as curious as they are passionate out there.
My mom doesn't like the complicated nature of making fresh coffee so she tends to only drink instant coffee. Whenever I'm home, I make her a fresh cup of dark roast French Press based on your method and she always tell me it feels super strong.
I always thought instant coffee was the strongest because it tastes super harsh, and psychologically it makes you feel as if it's waking you up.
I am surprised that filter coffee had higher caffeine than espresso. I always thought espresso's taste profile reflected the caffeine content, but I guess it's false.
In the case of expresso, don't forget that we're talking 36g of water vs 300
the caffein content per dl is much much much higher in expresso
My wife always says the same about my fresh coffee brews. She greatly prefers keurig coffees. It’s a good thing I’m not prone to doubting myself or I would have given up on home brewing a long time aho
Anyone who regularly drinks instant coffee and also drinks espresso based coffee knows that instant coffee has a lot less caffeine. That James had reasoned to a different conclusion and was therefore surprised by the test results just shows how little he drinks instant. 😁
I thought of that too but it didn't reduce his credibility in my view, lol. I attribute my knowledge of instant to my age.
Happy New Year! Hope you and the channel are doing well. I needed my James Hoffmann fix and am watching some old videos. Cheers!
All I can say is I would love a part 2 please!! Expensive and wasteful tests suck, but definitive and trustworthy answers are really cool!
I'd love to know about decaf coffee by comparison, and even - and I'm sorry to utter these words - tea! Green teas VS Black teas in comparison to coffee would be amazing. (I know there's still tonnes of variance in those, and would almost need a Bames Toffman channel to do those ones 😂😂 But if you have have the time, I'd love to know for sure!)
Awesome video though.
I agree, this would be great to get results from. I've been hearing for a long time about how green tea has more caffeine than coffee, but is it true?
Yes, I agree. The best way to reduce waste while maximising value of the money and resources that goes into the equipment is of course to make a video about it and share it. Especially when you have a lot of followers like James Hoffmann.
@Travis Humphery See, I've always heard Black tea has more caffeine! So definitely worth testing imo hahaha
@@Addersea Hopefully he will in a follow up!
As a researcher and having worked in a chromatography lab, I'm impressed by the tenacity and scientific rigor in your research. Also, you have great communication skills, making this content easy to follow it's remarkable. Awesome work!!
Never underestimate (coffee) nerds regarding rigor and tenacity. =)
Fascinating results! I was proved wrong about the light vs dark roasts!
I’d love to see a comparison between different teas. Especially teas like Sencha compared to Matcha or Gyokuro, or a comparison between Matcha and espresso. Even comparing teas from the different oxidation categories.
Oh yes i also Like to know this 🙌🙌
Perfect example of research (if that is what we are calling this) being misinterpreted. His data refute the hypothesis that lighter roasts leads to lower caffeine content in the brew, but nothing has been proven.
Only if research was so simple.
I would love to see caffine content for cold brew vs. hot brewed teas.
Amazing information. One of your best videos. Thank you.
James! I would love to see how a range of brew temperatures would change the amount of caffeine extracted. If the goal is to see how much caffeine gets detached from coffee molecules and get carried into the solution by the water molecules, then adding/subtracting energy might have an interesting effect!
I do have to wonder how the extraction of caffeine in the Aeropress is related to the cooling of the coffee.
@@clarkkent7973 I agree that this may represent why the caffeine extraction levelled out after 2 minutes. Most 'steeping' extractions like this are very temperature dependent, and the difference of a few degrees can drastically change what and how much of the compound you extract. This is seen very clearly in coffee as it becomes more bitter the longer it sits and when it cools as you are extracting different ratios of compounds over time and at lower temperatures, as well as with teas where different aromatic substances extract at different temps so a black tea is better at 100 C (for example) while a green may be better at 80 C. This is also one of the reasons (by no means the only one) why green tea has less caffeine than black.
By this theory, unless you are able to maintain water temperature through the entire extraction, you will see a drop in temperature, and therefore the caffeine extraction will drop off once you get below a certain temperature. This of course can be modified based on pressure, so a pour-over vs. an espresso would give different results due to the additional variable of pressure which acts to change the effective temperature of the solution (i.e. water boils at a lower temperature the lower the pressure, and at least some chemical processes also have a similar relationship).
I *strongly* expect temperature will not have a strong impact of caffeine extraction, and could plausibly even have a negative impact at low water quantities.
I also want to see how the caffeine vs soluble extraction changes with cold brew coffee. I've heard it said that letting the coffee steep at room temperature results in a smoother drinking experience, but I've also found that when I let it steep overnight in the fridge, the coffee tastes(?) stronger in a way
@@kevinpiala6258 especially when considering the way some people brew cold brew (in a similar "steeping" method to tea), it seems that temperature doesn't affect caffeine extraction by all that much.
I love how much James geeks out on everything that gives him a chance to approach coffee in a scientific way. You, sir, are amazing!
Great rundown on some very interesting and potentially complex information. Fun to watch!
Amazing content! This video made me understand why we feel what we feel after having a specific coffee through different methods. Also useful in choosing a specific coffee method for a specific occasion. This video is also a good guide for beginners to understand how ground coffee works differently than an instant coffee. Thanks again for a great video!
I would love to see cold brew caffeine content compared to French press (or other immersion method). Great video!
I would like to see the different cold brew methods, Asian Drop like Yama or Oji vs Totty vs leaving it in a french press over night then filtering the coffee. I would assume that the one that steeped the coffee longer would have more caffeine
Me too... Yes cold brew and night brew
Yes! I mostly drink french press (steeping for 4 minutes) and sometimes make cold brew (1 to 2 days in the fridge) myself.
Cold brew, that's the ticket! What's the caffeine content using this method?
@@jocastle746 Caffeine solubility in water is heavily depended on temperature, that much is known with certainty from chemistry. It is almost insoluble in cold water, so I would expect a cold brew to contain next to zero caffeine
What a wonderful time to be alive. You are looking for a recipe for coffee and then you stumble across a science paper in the form os a video which helps you understand some old questions we all had. Thank you so so much for keeping this knowledge field looking fresh and lightly roasted as always!
The world keeps getting better.
You're absolutely right with the contact time. It's the same reason, why there is a time written on tea bags for how long you have to soak them. Some components only start extracting after a certain time which alter the flavor
...and why experimenting with the time is worthwhile! I'm partial to green tea on an evening and find it has a much sweeter taste if brewed hotter and shorter than the instructions given. The wording on the box suggests the opposite should be the case, but there you go.
Absolutely love these deep insights, thank you!
The espresso vs filter is a huge one, might explain why I can drink a lot more from starbucks and not feel as buzzed or wired but when I drink my own filter coffee at home I can feel the caffeine in it. Very interesting results!
I'd be interested in the caffeine levels of decaf coffees that have undergone different processes, such as Swiss Water vs sugarcane. Thanks!
Seconded! Being pregnant I can only have a max of 200mg of caffeine a day and while a small latte isn’t going to max me out I’m still sticking to decaf because I’m a teeny bit paranoid, and now I’m so curious to know more about decaf coffees in general!
@@KDeanie I'd like to know how they make it! I've heard of Swiss Water, don't know what that actually is, and now I've heard of sugarcane as a process. I haven't a clue... 🙂
@@SaxonSuccess All decaf is bascaly the same process: soak the green beans untill they swell and become porous then wash out the caffeine. All that changes is the active ingredient that is used.
Swiss water is just that, they only use water but they have to boil the green beans many times to make it decaf.
Sugarcane uses Ethyl Acetate, a fancy way of saying a coupound of alcohol (from sugarcane) and vinegar, which is then washed out with water and steam.
The quickest (and cheapest) is Methylene Chloride (aka Dichloromethane) which is not toxic but not considered an organic process (so you can't have an "organic" coffee that is MC decaf).
I’ve heard that Swiss Water can extract slightly more caffeine than sugarcane, but I’ve found sugarcane decafs are slightly better to my taste. My favourite at the moment is from Workshop. It surprises me how difficult it is to find nice decaf, it’s definitely an area for growth and improvement!
@@justinleslie1 I am fully with you on this. I've recently switched to decaf in order to try and better manage some sleep issues, and finding a decaf that tastes even half as good as a £3 bag of beans from Lidl is a real challenge, let alone one that comes close to some of the better regular beans I buy.
A cordial salute for giving us some results, then actually saying "I don't understand this.", very open and honest.
It's so cute that James acts as if the coffee I drink at home every day is anything like the stuff he makes. I wish!
I would have cried of joy seeing some tests done on the "Low Caf" arabica varieties too, such as Laurina and Aramosa..
But finally some deep coffee science again :D Thank you so much !!
How much lower are they supposed to bev
@@Crepitom A lot ! look it up
I'd love to see more about how the caffeine concentration varies for decaf vs. non-decaf for the same brand. Anyway, awesome video as usual!
Great video and great info. Was totally surprised by the light roast vs dark roast results. 👍
That's because they are wrong
It's amazing how useful this actually is!
I think me and James have different definitions of relatively inexpensive
The only thing better than having a coffee after a days work is to have a James Hoffman video to watch alongside it
AFTER a day's work?! I'll forever be amazed at people with low caffeine sensitivity... and jealous
I don't even drink coffee (the wife does) but I'm obsessed with all the research you do. It's so fascinating
Excellent work, thank you.
I've been smashing instant coffee for years. When I have an expresso I can feel myself becoming scattered for a few hours.
Now I percolate a strong coffee in the morning at home. It leaves me noticeably more erratic and if I dare to have 2 then I'm a scattered mess for the next 10 hours. This includes my standard 3 more instant coffees.
1 strong percolated coffee is the equivalent of 2.5 instant coffees by effect from what I have noticed.
The biggest surprise for me is how much of this I took in without additional caffeine intake.
What would be interesting is seeing how some of these ‘strongest coffees in the world’ compare.
Maybe they know something we don't.
Of the few that I've been gifted over the past few years, all of them use robusta and so probably are signficantly higher than what's in the video. (they were also all super gross unfortunately)
If you did a whole series on this I would watch every minute of it 🧡
Thanks for this fascinating and informative video. It confirms something I see each day when I grind beans for my daily brew.
I am using a mix of beans right now that are mostly darker in roast colour. I noticed that it took 5+ seconds of extra grind time to get the same amount of ground coffee by weight when compared with my usual medium roasted bean. That result jibes with James' finding that darker roasts are less dense and therefore more are needed to get the same desired amount.
It also explains why I sometimes get a little more "revved up" after having an afternoon cup in addition to my normal two cups in the morning. It doesn't tend to happen when I'm using lighter roasted beans.
LOVE THIS!!! Absolutely fascinating. Thank you! I love coffee but caffeine not so much. Looking forward to your promised deep dive on decaf this year.
I heard a report of a recent report the other day that decaf coffee varies widely in it´s caffeine content; from the claimed 2% of the usual content to almost 50% in some "brands(?)". So I´d also love to see some results of decaf testing if you´ve time on your coffee break Braumeister Hoffman
I would’ve loved to see you do both green coffee and a proper black french roast in the roast level test
How would you grind the green coffee
@@liamblake937 with gusto
Green coffee has a lot of CGA. We tested that with this device
James was so, so animated in this video that I wonder how much of the pour overs he actually had sampled before the filming ;-) Loved the video. As someone who needs to be (a little) aware of caffeine intake for health reasons, this was super informative. Thanks to you and the team. All Best Wishes for the Festive Season to everyone !
Hames should do a screen lay over graphic for all the hand gesture movements somehow!
Extremely informative, Unexpectedly mind blowing.
All the results align pretty much with my own experiences as a coffein sensitive person actually! Love the video, it was really interesting
As an aeropress (and occasional french press) drinker, I'd definitely love to see where a variety of other brewing methods fall for caffeine extraction. It would be interesting to see how different bean-to-water ratios affect things, too (e.g. is it better to brew extra-strong aeropress/coldbrew and water it down american-style, or is it all the same?).
I'm thrilled you actually counted the beans in the various roast levels. Bean density is exactly what I thought of! I really hope we see this machine again in the hinted decaf video.
That was incredibly interesting. Thank you.
I'm very interested in how instant coffee from Asian brands (particularly Kopiko) match with brewed coffee. I notice a huge flavor difference for instant coffee vs nescafe. I actually genuinely enjoy the instant expresso I get.
Hi James, the phenomenon you're observing with the exponential increase of caffeine compared to extraction is akin to the process of size exclusion chromatography (or SEC). SEC describes the process of sorting molecules by their respective sizes; in the lab, you do SEC using agarose gel as the medium through which your molecules move, however in your case you can consider the non-soluble coffee particles and filter paper to be your gel matrix. SEC is based on the premise that as the gel matrix becomes less porous (aka when the coffee grounds are more packed together towards the tip of the cone), the smaller molecules are better able to run through the cramped matrix, while the larger molecules take longer to flow through. Comparatively, caffeine is a much larger molecule than water or many of the other chemicals that make up coffee, so it will necessarily take longer to flow through. This explains why you saw an exponential increase in caffeine as extraction increase; all your caffeine molecules are slow to join the rest of your coffee.
It was interesting to see a non-scientist go through the scientific process and come up with conclusions that were remarkably close to scientifically accurate, just without the fancy science vocabulary to go with it. Makes me think of all the renaissance scientists who kept accidentally proposing germ theory, but would describe it in terms of tiny beasts facilitating the transfer of disease or whatever.
P.S. the device your using looks to be a field kit for doing spectrophotometry. Basically, your machine shines a little light through your coffee sample and the machine calculates the amount of interference the light has in passing through the sample, thus measuring the density of the sample. If your machine was calibrated to some standard curve of known caffeine contents then it could tell you fairly accurately what each sample's caffeine content is based on the observed density. I don't think you probably did any calibration or standardizing to get that machine to work, so I'd question the accuracy of your measurement, but there's definitely some ways to beef up the rigor in these experiments and get some really interesting results.
Assuming you're right about the missing calibration: Is that just a matter of a fixed offset? So, all absolute values might be off by a constant number?
If that's the case, then it sounds as if all of James' conclusions would basically still hold true (the absolute numbers are not the important message of this video).
Or would calibration change more than that? I'm asking out of curiosity, because I have no idea how calibration works with this kind of machine.
Even if the measurements are not accurate in absolute numbers, they should be accurate with regards to relative caffeine content, no? For instance, we should be confident that espresso has less caffeine than filtered coffee.
I know you are not a fan of cold brew, but I would love to see the actual caffeine difference between cold brew and hot, obviously taking into account you use twice as much coffee to make cold brew. Edit to add, since I tend to brew up a quart of cold brew concentrate and drink it over several days, I'd be curious to see the difference in caffeine after the brew has been in the fridge for a few days, to see if it sort of degrades in some fashion..
I would assume it's more. Caffeine is quite water soluble. Shouldn't degrade since it's also quite stable. Caffeine pills and energy drinks last practically forever on shelves.
@@NiSE_Rafter I would assume the same, and always have assumed it would be pretty much stable in the fridge but I think it'd be neat to see it tested.
This explains a lot. I tend to drink instant at work all through the day, but if I don't get my filter coffee in the morning, those cups don't do much for me.
This particular video introduced me to your channel a few weeks ago, then hooked me with your rigour and clarity, and now I'm grinding (😉) my way through your back catalogue. I got hooked on drip and percolator coffee nearly 40 years ago, played with Melitta and French press for a while in the '90s, and got hooked on Aeropress about 10 years ago. Now I'm branching out again thanks to your channel! (Your Aeropress series greatly improved my brews, and earned my trust in your expertise.)
And now that the niceties are over, the true reason for my comment:
Nice vase! Is there a story behind it?
I actually have a background in STEM, and wanted to say I loved this video. I think there are a few other factors affecting the solubility that might explain some of the discrepancies you noted. Specifically that solubility is not isotropic with fluid temperature and pressure, which would help explain the difference in rate of extraction between caffeine and total dissolved solids. You could test for this by doing your same 5-cup split of a brew, and altering the water temperature (ie 212, 202, and 192 F for an espresso) and by altering the pressure by using a manual lever machine like one of the flair machines with a pressure gauge. Happy to help design an experiment if that would be helpful!
I used to work at a coffee and bagel shop. Idk how many times I told people that dark roast has less caffeine than light roast! I'm weirdly happy to be wrong because this video was so damn enjoyable. I look forward to future experiments!
And i don’t know how many times I’ve been told that by barristas! But I’m wondering if the lower caffeine theory might be true for really dark roasts.
@@TamarLitvot ב''ה, I have a sense that if you know the taste of caffeine and can taste it in coffee, you can taste the supposed burn-off, and would wager the early 2000s standard Starbucks roast I'm not particularly fond of is right around that point - "roasted enough" to some palates and "why did you do that?" to mine.
It's so cute when people actually learn science and counterargue their own counterintuitive assumptions. Good on you for finding this out yourself!
I’m so happy you made this video!!! I made a comment a while ago asking for you to do this because I was certain you were the only one who would and COULD give me the content I wanted here. After hours of research, I concluded that this information is simply not available on the internet. You DID NOT disappoint. THANK YOU!!!
The espresso vs. pour over caffeine difference really didn't surprise me because I drink double espressos all the time but when I drink a single cup of V60 I always get jittery
Same experience here. I stick to espresso because of that. No jitters even with two double espressos.
I too, thought this was common knowledge.
It’s because the espresso has less water to extract caffeine. Caffeine is only moderately water soluble, so espressos generally saturate quickly. That’s also what happened in his timed steeping experiment.
It would be super interesting to see you test a little outside the realms of coffee to see the differences. Maybe test some tea types and drinks like coca cola to show the differences between them and coffee.
🤞🤞Tell Max I sent you to him about a business investment...
Yerba mate and guarana extractions could be interesting as well. Maybe even raw cocoa powder.
I like to see green tea, black tea and matcha (for the hipsters ;))
I love the way you put the fact on your videos, it is very clear and understandable. Thank you. I'd like to learn if you had the chance to measure the caffeine level in cold brew coffees.
The reasoning for instant coffee having more caffeine made sense to me, but I had always experienced less of a caffinated feeling. It takes a very huge amount of instant to meet the strength of regular fresh coffee, and in periods where I got very used to instant and went back to drinking fresh, it was like I got hit by a truck of caffeine. I've also experienced somewhat similar differences in caffeine in dark roasts. Some of the strongest dark roasts I had made my head spin, but I simply don't drink a lot of dark roast so I always thought it was just the brand. Pretty cool to see the numbers confirm that!