Green Bean Grading for Beginners

Ok, grading green beans for the beginner coffee enthusiast.

Size: Acceptable sizes are generally considered 13/64-18/64". Larger beans are considered more robust with flavor, so ideally your sample has a higher concentration of larger beans. How do you know this in any reasonable time frame? Glad you asked, no it's not by using a micrometer and hand measuring each bean individually! Some clever person figured that taking a piece of metal and puncturing it with 13/64" and the next with 14/64", and so on until all acceptable sizes are had. Then you take your sample from the smallest size to the largest, counting or more preferably weighing each group you can assign the percentages per size. Sizing complete!

Defects: some defects are obvious, and that's where we'll spend our time. Fragmented beans, malformed, insect attacked and discolored. Broken or fragments are pretty easy to pull aside. Malformed beans again are pretty straight forward, with little practice you'll find most of them. Shells are the easiest malformed type to find, they are essentially the bean forming so that it is hollow with an opening, like a shell. Insect attacked beans often have small bites taken out of the bean and are surface based. Some insect damage can look like a fragment, with an irregular edge or serrated from the biting. Discolored beans to focus on will be the blacks, half blacks and or pale green's which often indicates a problem with the drying process. Also pay attention for shiny beans another common washing/drying problem.

Now, it's good to take a decent sample, say 50 grams. This is enough to grade, but not so tedious you'll want to give up. It's great to have 6 identical dishes to sort into, when you're done you'll weigh each group to get the defect %. The 6 bowels you'll identify as 12/64", 19/64", Fragments, Malformed, Insect and Discolored.

In the end you'll have three sets of numbers that will indicate the quality of you green bean sample, which directly translates into what ends up in your cup. The first number is the the % of outlier beans in size, so any beans smaller than 13/64" and larger than 18/64" as a percent to the total weight. The second indicator is the total defect % by weight by adding up all 6 dishes against the total weight. Finally you have a related set of numbers and those are the 4 individual % of total weight for the non-millimeter defects.

Now before someone cries wolf and cites one of several sanctioned methods, let me remind you that this article is intended for beginners. To give them their first exposure to identifying a good green bean to purchase as green or as roasted. I'll write additional Green Bean Grading articles that will conform to a standard in the future.

Depending on how dedicated, obsessed or just in the pursuit of the best cup, you'll do this for all of your green bean lots and discard the defects. This also will eventually make your supplier better if you share your results with them!

Good luck and have fun,

the BeanGuru

Breaking News: Savaya Coffee is now Open

So I stopped in to speak with Burc ( a Turk ), owner of Savaya Coffee on the South/West corner of Broadway and Craycroft. He's been working on opening the coffee shop for nearly 18 months.

The exciting piece is that Burc, so far has the best understanding of what a roast profile means here in Tucson. He had just completed a nice El Salvador Bourbon and the beans were beautifully roasted just past the first crack by my estimation. No oil on the skin of the bean at all. By looking briefly, I'd give the beans a definite grade A rating and the roast was just as high. I saw only two scorch marks against a vat of beans. This is very promising.

Burc was kind enough to also hand me a sample which I'll grind in a couple of days to let the beans properly rest. Normally, this is about a 72 hour period, depending on how patient I am...
He also agreed to host a cupping in the future, nice!

I sampled his Sumatra freshly brewed, it was tanic in a bold sense and short on the pallet when hot. After a few moments the flavor changed quite dramatically to an almost pungent Meyer lemon flavor consistent with a Bourbon. Very unusual for a Sumatran, but was a very good cup.

Just based on this limited experience, this is my new hangout for a mid-day coffee. Good to have ya Burc!

Let's Get Cupping

Ok, I've been back in Tucson for almost a year now and there is much to be desired from the local roasting scene. The trend is to roast well after the second crack, great if you want to club your tongue or cover up inferior beans, but not so great if you'd like to enjoy a nice South American coffee. Details and the true flavor have been destroyed.

So I've decided to educate 'Zona pallet's. I've begun working with local roasters and coffee houses to setup "cupping" events!

If you'd like to learn about selecting, roasting, profiling coffee - please tune in as I'll post dates of these events. Donations are accepted to offset the cost of cupping equipment.

What happens at a cupping?

3 Samples, usually one from each region (America's, Africa, Indonesia)
Green Bean grading
Evaluate the Roasted sample
Grind and examine
Brew in cup
Sample
Describe

I'll describe these steps in more detail in a later post.

Keep checking back for our inaugural cupping!