Espresso tastes sour or bitter because the shot was not extracted the way that coffee needed. Dialing in espresso is the process of fixing that, one variable at a time: dose, grind size, yield, and time. This guide walks through the whole process, from your first shot to a repeatable recipe you can write on a note card.
The Four Core Variables of Espresso Extraction
- Dose. The weight of ground coffee going into the portafilter. A common starting point is 18 to 20 grams for a double shot, though basket size dictates the exact range.
- Yield. The weight of brewed espresso coming out of the cup. A standard target is roughly 1:2, meaning an 18 gram dose aims for about 36 grams of liquid out, though ratios from 1:1.5 to 1:3 are used intentionally depending on style.
- Time. How long the shot takes to pull, typically around 25 to 30 seconds from the start of the pump to the end of the pour. This is a guideline, not a hard rule.
- Grind size. The main lever for adjusting time and flavor. A finer grind slows the shot down and increases resistance, while a coarser grind speeds it up.
A Simple Dial-In Process
- Start with a known dose and ratio. Weigh 18 grams in, target 36 grams out, and use the grind setting recommended by the roaster or your machine's manual as a starting point.
- Pull a shot and time it. If it runs noticeably faster than 25 to 30 seconds, the grind is too coarse. If it runs much slower, or stalls entirely, the grind is too fine.
- Adjust grind size in small increments. Make one change at a time, then pull another shot. Espresso grinders are sensitive, so small adjustments often have a bigger effect than they would on a drip setup.
- Taste, don't just measure. Numbers get you in the right range, but taste is the final judge. A shot that is sour and thin is usually under-extracted: it needs a finer grind, more time, or a bit more yield. A shot that is bitter, harsh, or burnt tasting is usually over-extracted: use a coarser grind, less time, or a lower yield.
- Lock in and repeat. Once a shot tastes balanced, sweet, and well rounded, note the dose, grind setting, time, and yield so you can return to it, since grind settings often need small adjustments as beans age or humidity shifts.
Common Problems and Fixes
- Sour, thin, weak shot: likely under-extracted. Grind finer, extend time slightly, or increase yield.
- Bitter, harsh, burnt shot: likely over-extracted. Grind coarser, shorten time, or reduce yield.
- Shot runs too fast no matter the grind: check your dose and tamp. A light or uneven tamp can let water channel through the puck instead of extracting evenly.
- Inconsistent shots from the same setting: look at grind consistency, dose accuracy, and whether the coffee has rested since roasting, since very fresh coffee behaves differently as it degasses over its first several days.
- Channeling (uneven extraction): improve distribution before tamping and keep the tamp level. A wobbling tamp is the most common cause.
Dialing In Different Roasts
Darker roasts, like Riserva Nero, tend to be more brittle and grind finer at the same setting than lighter roasts, so expect to adjust when switching between coffees. A medium-dark blend built for milk drinks, like Riserva Velocità, often performs well pulled slightly shorter to keep its body from getting lost under steamed milk. Dialing in is always specific to the coffee in front of you, not a universal setting you can carry from bag to bag.
Which Beans to Dial In With
A fresh, consistently roasted blend is the easiest place to practice, because the flavor stays stable day to day. Browse our espresso coffee beans collection, roasted in small batches with the roast date printed on every bag, so you always know how fresh your beans are. If you are not sure which coffee fits your setup, answer our Find Your Roast quiz and we will point you to the right bag.
Frequently Asked Questions
What does dialing in espresso mean?
Dialing in means adjusting grind size, dose, yield, and time until a shot tastes balanced, then repeating the process each time you change coffee, grinder setting, or machine.
Why does my espresso taste sour?
Sourness usually means the shot is under-extracted. Grind finer, extend the shot time, or increase the yield so more flavor dissolves into the cup.
Why does my espresso taste bitter?
Bitterness usually means the shot is over-extracted. Grind coarser, shorten the shot time, or reduce the yield. Very stale beans can also taste bitter no matter what, so check your roast date.
How long does it take to dial in a new coffee?
With a scale and a repeatable process, most people get a balanced shot within three to five shots. Recording dose, grind, time, and yield each time makes the next bag faster.
Should I dial in espresso with light or dark roast?
Dark and medium roasts are more forgiving for beginners because they extract more easily. Light roasts can make outstanding espresso but need finer grinds and tighter control.
Related guides: best coffee beans for espresso and best beans for home espresso machines.