Friday, May 27, 2011

On Constructing a Brew Chart

How do you make a brew chart for a brew method that hasn't existed before? After all, I'm still trying to understand exactly how the double catcher press brews. I'm still getting spotty results. Some brews are great, and others are unremarkable -- and I don't always know why!

This evening, thanks to a good conversation with Velton Ross of Velton's Coffees, I finally feel like I can describe and understand the critical instruments that can guide me across this uncharted terrain. What are they? First: proper brew temps and second: proper grind / dose / time ratio. Coffee extraction isn't magical, and while double catcher extraction processes are still unexplored, thankfully the fundamentals of extraction are established.

It all crystallized for me tonight as I watched the same roast of Honduras blossom over the course of three brews. Velton's outside perspective popped the problem open after each of the first two cups, getting my mind out of it's rut of assumptions and encouraging me to look at some other variables in the cup that I'd dismissed.

What changed? Cup 1 tasted under-extracted, like tea, while the coffee catcher bed exploded with aromatics that were not extracting into the cup. I pushed the grind 3 notches finer and tried again. This time the cup was much more thoroughly extracted - but it lacked the acidity, fruit and florals that had emerged on the cupping table. Velton suggested upping the brew temp, observing that the bloom-free water was likely way below brewing temps when the top catcher was pulled at 3 minutes and full brewing began.

He was right. For cup 3, I tried pouring directly from the boiling kettle and gauging my water temp each minute. The temperature really dropped off, even with boiling water to start the brew. For cup 3 I measured 198, 190, 188 and 180 at minutes 1-4, respectively. The dramatic drop on minute 4 happened almost instantaneously as I pulled the top coffee catcher and released the coffee fully into the water.

Regardless, near-proper temps made a huge difference. The bright florals and fruit jumped out of the cup. There was an enticing fizziness, a carbonated "pop" to the cup that I'd observed in previous delicious double catcher extractions. The body and middle / dark notes were still solid, though not as well-developed as they could have been. The extraction was still slightly watery, so I know I have more dialing in work ahead of me. As I start to track fundamentals, though, that's actually just what I'd expect, as I know my brew temp is still considerably below the 195-205 that I want to hit throughout the 4 minute brew process.

I realize finding a method of achieving correct brew temp in the French press is going to be tough. In fact, I know a lot of my barista friends who haven't figured it out with a traditional press method either. I'm convinced it can be done. Specifically, I'm convinced there's a way to bump the initial temp up 7 degrees to 205 and way to block the massive heat exchange during the third minute coffee catcher pull.

What did I learn tonight? Brew fundamentals stay the same, regardless of the novelty of the brew method. Nailing down my temperature will allow me to drop my dose and tweak my grind to the actual range for double catcher extractions. I feel like I have a compass I can use to dial in my double catchers - and to check my pour over and espresso and siphon too.

It's good to get back to basics.

Notice the clean press and the pulled bed, both key features of the method.

- Nate


  1. Have you experimented with thermal French Presses? Single-wall glass won't hold temp. that well. Also, the Espro Press might be worth a look.

  2. Maybe. I've thought about double wall / stainless for sure. I think the challenge is that carafes with greater mass actually suck more heat from the system until temperature equalizes. In other words, a double wall carafe is great for keeping hot coffee hot. But the extra material to heat up initially might make achieving a correct brewing temperature even more difficult than in a single wall press.

    BTW, I've measured temps with a traditional press technique and the single wall does hold temperature well if starting with boiling water. The double catcher technique allows a lot more heat transfer, and that's what I need to figure out how to address.

    Thanks for the input though. It's still a process in development and I don't know what the most elegant solution is yet.