One Bean at a Time: The Grind Variable Hiding in Plain Sight

Simon Gautherin dropped beans into his grinder one at a time. Not because he was short on coffee, but because he was chasing something most baristas never think to measure: the moment before grinding begins.

The technique is called slow feeding, and it helped Gautherin finish second at the 2026 World Brewers Cup. In blind tastings during his preparation, he consistently chose the slow-fed coffee.

I found it cleaner, with more clarity, less dryness, and less bitterness.

Simon Gautherin

For Sofia's specialty coffee scene, where baristas at cafés like those in Blue Bag's network of partner locations already obsess over water temperature and dose weight, slow feeding represents the next frontier in dial-in precision. It costs nothing, requires no new equipment, and produces measurable results.

What Actually Happens Inside the Chamber

When a full dose enters a grinder at once, the chamber crowds. Beans collide with each other, with the burrs, and with fragments already breaking apart. Nate Secinaro, founder of ARO Espresso, believes these interactions explain most of the difference.

What is actually changing is the interaction between the beans and the burrs, but probably more importantly, the interaction between the beans themselves while they're being ground.

Nate Secinaro

With heavily loaded burrs, coffee contacts both burr surfaces and other fragments before leaving the chamber, causing extra fracturing, what Secinaro calls regrinding.

Slow feeding leaves the chamber less crowded. Less load on the motor. Fewer bean-to-bean collisions. The result: a coarser average grind with fewer fines at identical settings.

The Numbers Tell a Clear Story

Independent testing by Kaffeemacher found measurable effects on particle size. At the same grind setting, slow feeding produced a coarser average grind and noticeably fewer fines across two different coffees.

Secinaro ran his own tests on a Eureka Mignon XL using a 100µm sieve. His slow-fed samples produced far less material below that threshold than traditionally ground samples. When he pulled espresso without changing the grind setting, the slow-fed shots ran much faster.

Obviously shot time isn't a direct particle size measurement, but when you combine that with the sieve results it gives a pretty clear picture.

Nate Secinaro

A 2024 study by Samo Smrke, André Eiermann, and Chahan Yeretzian confirms why this matters: higher shares of fines reduce an espresso puck's permeability, slowing flow and lengthening extraction time.

The Trade-Off Nobody Mentions

It makes coffee different.

Gautherin found the technique most useful when chasing clarity in filter coffee, individual flavours became easier to identify. But Secinaro offers a caveat:

If you really like that heavy, syrupy traditional espresso profile, reducing fines isn't automatically going to make the coffee 'better.' It's just a different profile.

Nate Secinaro

Fines contribute to body, intensity, and mouthfeel. Reducing them shifts the cup toward transparency and away from weight. For a delicate Ethiopian natural, that might be exactly right. For a dense Brazilian espresso blend, it might strip away what makes the coffee work.

Claims about static reduction remain unproven.

Static is harder because I haven't directly measured electrical charge.

Nate Secinaro

Repeatability Beats Slowness

The real insight isn't about feeding as slowly as possible. It's about controlling the rate and repeating it consistently.

Hand-feeding introduces its own variable. Automation solves this, devices like the ARO Slow Feeder and CremaLoop meter beans at adjustable rates. But the principle matters more than the product: if you can't repeat your feed rate, you've added noise instead of signal.

Rona Ramadani of Eureka frames it carefully:

The way beans enter and interact with the burrs can affect how they are broken down and therefore the distribution of particle sizes. It is one of several variables that can influence grinding performance, together with burr geometry, motor speed, alignment, and grind setting.

Rona Ramadani

Feed rate could become independently adjustable on future grinders, the way some models now let users change RPM. For now, it's a manual technique worth testing during dial-in.

It's not magic, and it's not going to compensate for the wrong coffee, poor roasting or bad brewing. It's another tool.

Simon Gautherin

For baristas who already weigh their dose to the tenth of a gram, slow feeding is the logical next question: what happens in the seconds before those beans hit the burrs?