Dialing in is the single skill that separates people who love their espresso machine from people who regret buying it. It's not complicated once you understand the logic, but it takes a few shots to get right for each new bag of beans.
Begin with an 18g dose producing roughly 36g of output (a 1:2 ratio) in 25–30 seconds — a reliable starting point for most medium roasts.
Sour, thin, watery: under-extracted — grind finer or extend the shot. Bitter, harsh, burnt: over-extracted — grind coarser or shorten the shot.
The most common mistake is adjusting grind, dose, and tamp pressure all at once. Change only the grind size first, pull another shot, and taste again.
Once your shot pulls in 25–30 seconds at your target ratio and tastes balanced, stop. Over-tweaking a shot that already tastes good is a common beginner trap.
Adjusting grind size, dose, and shot time until espresso extracts properly — neither sour/thin nor bitter/harsh.
Most shots should take 25–30 seconds to reach roughly a 1:2 dose-to-output ratio.
Sour espresso is almost always under-extraction, from too coarse a grind or too short a shot time.
Related reading: How to Make a Perfect ShotHow to Backflush