Observations From Today's Brewing Lab Work.
I had a great day in the Batdorf Brewing Lab today, and I want to share some of the findings. First off, I am currently researching the affect degassing has on coffee brewed with the Clever, as a base for how roast date affects manual brewing. It became apparent to me in the past week, when every coffee I did was taking at least a minute longer when brewing with the Clever. Instead of a four minute brew time, I was getting 4:45-5 minutes. And it was frustrating, because the grind and dosage were the same. A post from my friend Sean Stewart in Nashville brought up the fact that they were having a problem getting a steady brew time, and allowing it to degas for several hours made a difference. So I decided to do a little test.
Yesterday, I brewed a coffee that was roasted yesterday morning. Remember, it's hard to get coffee that's older than a day in the Roastery, it's all going out, so it's gonna be no more than a day and a half old tops. Sure enough, the brewing took 4:45, a whole 45 seconds longer than I like it at 4 minutes. So, I left some out on the counter to brew today. And brewed it today. And sure enough, it was 4:15, a whole 30 seconds off the brew time of yesterday, and I am imagining that tomorrow it should be perfect at 3:45-4:00. So, today, I put that theory to the test and it was correct, as per Sean Stewart's observation. I am going to figure out the whys and the science of it next.
The other experiment I did, was I took our Ethiopia Harrar, which was also roasted yesterday morn, and brewed it up. I changed a couple of things up based on some work my fellow Training and Education team member Will Frith did with the V60 out in Olympia. He uses a 21grm dose for 12oz, whereas I was using a 24grm dose. He's at 362grms of water. He ends up with a total brew time of 2:30-3:00min, mine was 4min. So, I tried his way. He had posted his grind was Paper Cone, which I tried to translate to Paper Filter on the Ditting. First brew, 4min. Made it more course, a half increment. Brew time, 3:15. Made the grind even more course, moved it another half increment to 6. 2:45. Extract MoJo'd it. It had a 18% extraction on 1.19TDS. I knew I wanted to increase the extraction while cutting my total time down to 2:30, and I knew that to do that I'd need to make the grind even more course. So, I moved the grind to 6.5, and thought about the three T's for brewing coffee: Time, Temperature, and Turbulence. I learned a good bit about turbulence affects the extraction from Scott Rao's book, "Everything But Espresso."
So, I figured I could up the extraction even though I made the grind more course by stirring more, keeping more of the grinds in the water the whole process. So, I changed the grind, brewed it, stirred it three times. After the initial pour burst to the top. Then, at 300grms. Then, at the end, at 362grams. Total brew time, 2:35. MoJo'd it. Extraction percentage 19.13 with a TDS of 1.24, which is a great extraction. But how did it taste, since that's all I really care about? Best brew of them all. Perfectly balanced, nice fresh baked blueberry muffin taste. For myself, I really have learned to love the power of the gentle stir.
Also, I was joined by Nathan Slabaugh, a.k.a. the Circus Coffee guy. He comes and visits us everytime the circus is in town, and we talk shop, brew coffee, and the sort. If you don't know him, he runs a coffee cart for Ringling Brothers Circus, travels with 'em, supplying them with espresso drinks and such. Even roasts his own coffee. Craziness, I tell ya, the stories he tells. Craziness. You can follow him at @CircusCoffee on the Twitters.
So, that's what I learned today. I was asked to share it with others, so here ya go. Any of you have questions or thoughts on this?