When choosing green coffee beans at the source, or deciding whether to buy green coffee beans shipped in from the source, Young Jun Cho of Prism Coffee Works doesn't just cupping. He always brews an espresso and tastes it. This is because the flavors from the cupping often don't show up in the espresso, and vice versa.

It's always important for him to get to the brew setting quickly to make espresso cup notes because he doesn't have a lot of green bean samples. He used to drink a lot of espresso to get to the brew setting, and he was afraid of running out of green bean samples. However, since using the Belka filter, the process has become much faster and less tasting.

First, he brews a cup for as long as it takes to get the lowest EC. Then, as a rule of thumb, he identifies a good EC level at which to end the brew and ends the second brew at that EC point. Once he tasted it, he was able to start making cup notes immediately.

Cho's method could be very useful for roasters and baristas as well.

First brew to check cupnote. The initial flow rate started rather quickly at 2.5 g/sec, and the secondary flow rate was maintained at 3.5 g/sec. From 15 to 20 seconds, the EC seems to stagnate instead of dropping, which is the appropriate end of brewing point that Youngjun Cho has found empirically. Now we can do a second extraction that ends at that point.

Secondary brew to confirm cupnote. The initial flow rate was 2 g/sec and the final flow rate was 3.7 g/sec, similar to the first brew. This was a fast extraction, 45 grams in 15 seconds, but it was very consistent with the first extraction. Cho was able to taste this shot and determine the cup note. This is a know-how we can't wait to learn.