Brew Log: Boma AA Kenya Micro Lot 12 — French Press, Two Grind Sizes

Date: June 27, 2026

This is a simple field note. No espresso machine involved. Just a French press, a manual grinder, and a Kenya natural that deserved some attention.

The Bean
Boma AA Kenya Micro Lot 12. Natural process. Light roast.

The Setup
Brewer: French Press
Grinder: KinGrinder K6 (manual)
Water: Boiled in electric glass kettle, poured at near-boiling
Steep time: 6 minutes (both brews)

Two Brews, One Variable Changed

Brew A — 75 clicks
Acidity is present and clean. The natural sour character of the Kenya is there. Light body feel. The cup is bright but not aggressive.

Brew B — 35 clicks
Acidity holds at roughly the same intensity — it didn't sharpen or become harsh as expected with a significant grind reduction. What changed is a noticeable soil and earthy character that wasn't prominent in Brew A. The cup has more weight to it.

What This Tells Us

The acidity stability across such a large grind step is the first interesting signal. Kenya naturals can turn sharp quickly when pushed. This one didn't.

The soil note emerging at 35 clicks on a light roast is origin character, not roast artifact. Light roast means minimal pyrazines or Maillard-derived earthiness — what you taste is the bean's terroir unlocking at sufficient extraction depth. The coarser grind at 75 clicks couldn't reach it. The finer grind did.

In 3DDP terms: grind fineness here is acting as a proxy for extraction depth in the Time domain. Steep time was held constant at 6 minutes. Temperature was consistent. The only variable was grind. The soil note is what the T domain revealed when given more surface area to work with.

Why This Belongs on a MeeBaa Blog

The S01A-9Bar and S01B-9Bar are espresso machines. French press is about as far from 9-bar extraction as brewing gets. But the 3DDP framework — Time, Heat, Pressure as the three irreducible extraction variables — applies across every brew method. French press is a pure T-H system with no meaningful P contribution. Watching how flavor compounds unlock across grind sizes in that environment isolates the T domain cleanly, in a way espresso cannot, because espresso always has P in the picture.

Real world brew data, even from a French press, builds the empirical layer underneath the framework. The framework is only as credible as the observations that support it.

This is one observation. More will follow. Next time, we will make espresso and latte with the same bean.

— Aris Barro