Dialing in has a reputation for being fiddly, and the fiddliness is almost always self-inflicted. People change the grind and the dose and the tamp all at once, taste something different, and have no idea which change did it. Here is a method that converges.
Fix two things, change one
Choose a dose and do not move it. Eighteen grams in a double basket is a sensible default; whatever your basket is rated for is better. Weigh it every time.
Choose a yield and do not move it. Twice the dose is the standard starting point — 18 g (0.6 oz) in, 36 g out. Weigh it, do not eyeball the cup.
Now the only variable is grind, and the only measurement is time. You are aiming for that 36 g (1.3 oz) to arrive somewhere between 25 and 32 seconds from the moment you start the pump.
Read the clock, not the taste
- Too fast — the shot hits 36 g (1.3 oz) in under 22 seconds. Grind finer.
- Too slow — it is still crawling past 40 seconds. Grind coarser.
- In the window — now, and only now, taste it.
Time is a proxy for extraction and it is far easier to judge than flavor when you are starting out. Get the time right first, then use taste to fine-tune.
Then taste, and adjust in one direction
Once the shot lands in the window, taste tells you where to go:
- Sour, thin, salty, sharp — under-extracted. Grind slightly finer, or extend the yield to 38 g (1.3 oz).
- Bitter, dry, harsh, hollow finish — over-extracted. Grind slightly coarser, or pull back to 34 g (1.2 oz).
- Sweet with a clean finish — stop touching it.
Why this fails, and it is usually the grinder
If a single click takes you from gushing to choking with nothing in between, the method is fine and the grinder is not. Espresso lives in a narrow band of fineness and needs fine steps inside it. That is the whole reason we recommend grinders by their espresso adjustment range rather than by burr material.
The second common cause is channeling, which produces sour and bitter simultaneously and cannot be dialed out. Stir the coffee bed with a WDT tool before tamping and try again.
New beans, new roast
Each new bag needs a little re-dialing, usually one or two steps from where you were. Darker roasts extract more easily and generally want a coarser grind and a shorter ratio, such as 1:2 or less; light roasts want finer, longer ratios up to 1:2.5 and hotter water. Beans in the first days after roasting release a lot of CO₂ and behave erratically, so rest them for about a week before judging a recipe.
Pressurized baskets
If your machine came with a pressurized, double-wall basket, the method above does not apply: the basket creates the resistance, not the coffee, so grind and time barely matter. Switch to the single-wall basket if one is supplied, or accept that pre-ground coffee and a pressurized basket will give a consistent, if limited, result.
What people want to know
How many shots should dialing in take?
Three to five with a new bag if you hold dose and yield constant. If you are still wandering after ten, you are almost certainly changing more than one variable per attempt, or your grinder cannot resolve finely enough in the espresso range.
Do I need to re-dial for every bag?
Yes, and often within a bag. Roast level, density and age all change how the coffee grinds and how fast water passes through it. Fresh beans degas and run faster; the same bag at three weeks usually needs a slightly finer grind.
What if the shot tastes sour and bitter at once?
That is channeling, not extraction. Water has found a path around part of the puck, so some coffee is over-extracted and some barely touched. Grinding differently will not fix it — stir the bed with a WDT tool before tamping.
Last reviewed 30 October 2026
