Agitative
The Journal
The Coffee-to-Water Ratio Explained: How to Dial In Every Brew Method
What a 1:16 ratio actually means, why it's the single biggest lever on strength, and how to pick a starting ratio for espresso, moka pot, French press, pour-over, drip, and cold brew.
A Complete Grind Size Guide: Matching Your Grinder to Your Brew Method
Why grind size has to match contact time, what happens when it's wrong in either direction, and a method-by-method reference from Turkish coffee's near-powder to cold brew's extra-coarse grounds.
How to Bloom Coffee Properly (And Why It Matters)
The science behind the first small pour in pour-over brewing, why fresher beans need a longer bloom, and how to tell when the bloom has actually finished doing its job.
TDS and Extraction Yield: What Every Home Barista Should Know
How a refractometer reading becomes an Extraction Yield percentage, what the SCA's 18-22% gold-cup range means in practice, and how to use both numbers as a diagnostic rather than a rulebook.
How Much Caffeine Is Really in Your Coffee?
Why brewing method matters less to total caffeine than most people assume, why a small espresso shot and a big drip mug can land in a similar range, and why any estimate should be treated as a range, not a precise figure.
Espresso vs. Moka Pot vs. Chemex vs. Siphon: Choosing a Brew Method
A side-by-side look at four very different ways to make coffee — pressurized espresso, stovetop moka pot, gravity-fed Chemex, and the theatrical vacuum siphon — and what each one is actually good at.
Water Chemistry and Coffee: Why What's in Your Kettle Matters
Coffee is mostly water by weight, so its mineral content quietly shapes extraction and flavor — what hardness and alkalinity actually do, and simple ways to improve the water you're already using.
Fix Your Ratio First: The One Check Before Any Other Coffee Fix
Before you buy new beans, a new grinder, or a water filter, weigh your dose and water and check the ratio — a worked example of how far off a quick scoop-and-splash habit can drift, and why this is always the cheapest thing to rule out first.
What Extraction Yield Actually Tastes Like
The 18-22% gold-cup band isn't just a number — it maps onto what's dissolving out of the grounds and in what order. A worked example at three TDS readings on the same recipe shows exactly where sour, balanced, and bitter come from.
The Grind-Size and Contact-Time Relationship, Explained
Grind size and contact time aren't two independent settings — they're one relationship, and understanding the geometry behind it explains why espresso's 25 seconds and cold brew's 24 hours both work, using the same physics.
What's Actually Happening During the Bloom
Our how-to guide covers the bloom's timing; this one goes underneath it — where the trapped gas actually comes from, why escaping gas causes channeling specifically, and a worked table of bloom times across three roast ages.
How to Diagnose a Sour or Bitter Cup, Systematically
A step-by-step order of operations for a cup that tastes wrong — rule out ratio first, name the specific symptom, then work through grind, temperature, and contact time in the right sequence, with a full worked example.