Sorting Out Green Bean Defects

WOLFF WEEKLY VLOGG 028 | Kelsey Carr Sorting Out Green Bean Defects
Welcome back! Today we’re going to be looking at another component of the green grading process. So last time we looked at screen sizes, and this time we’re looking at identifying defects. So defects are basically malformed beans and they are going to result in unfavourable flavours or taints in the end cup and we don’t want these.
So we look for defects at two phases, just like we did with the screen grading. So first of all, when we receive a sample of coffee which we might want to purchase, we go through and we look at the amount of defects. Secondly, when we have signed off on that coffee, it arrives into the Wolff Haus, we reevaluate the coffee and check that the range of defects is still in the acceptable.
So defects we look to the Specialty Coffee Association of America to guide us here in identifying and categorising them. So they differentiate between Category One, or Primary, defects and Category Two, Secondary defects. So there can be multiple beans which make up a total defect. For example, for a Category One of the severe insect damage, which is three or more bites per bean, you need five of them to make a full defect. But for a Category One Black, so an opaque black bean, you only need one to make a Category One defect.
The tolerable range for us, again we’re guided by the Specialty Coffee Association of America, is 0 of the Category One primary defects and under five of the Category 2 secondary defects. That’s for a 350g sample.
So what we’re going to do now is look at the process which we go through to identify these defects. We grab our coffee sample, ideally 350g, or whatever you have on hand. Then we put it on a green grading matt, which is just a black matt. Ours is great because it has a list of the defects on it, super useful!
We then go through and sort out, grouping the defects. Then we basically list out how many of each one we have got and then identify how many Category Ones and how many Category Twos. Here again we use Cropster just to identify and keep a track of all of our green grades for coffee.
So there are a few different defects and some of them are more tolerable than others. We don’t expect every coffee to come to us in mint condition, every bean being polished and the exact same size. For example, chips and cuts, if they’ve not got infected, that’s totally fine, as long as they’re below our tolerance for it. Whereas if you’ve got coffee coming in and it’s got one or two blacks, couple of sours and a rock, obviously that’s not a coffee we’re looking to purchase.
So that’s the green grading process. So just to summarise, green grading looking for defects is an extremely important process for us. Defects can result in negative flavours in the end cup, throughout the entire roast, it’s something we don’t want our customers to be drinking. Even worse than that, we’ve also got foreign objects like sticks and stones which can damage equipment. We don’t want to be taking out anyone’s grinder any time soon.
So we have a range of acceptable defects and as long as there’s no Category One and there’s under five Category Two then it’s acceptable.Anything that’s not acceptable, we just don’t purchase. So looking for defects is important. Obviously the sensory analysis is more important, but we’ll get to that at a later date. See you!