How to Dial In a Coffee Grinder for Espresso

"Dialling in" is the process every espresso drinker eventually has to learn: adjusting your grinder and recipe until a specific bag of beans tastes balanced rather than sour or bitter. It sounds technical, but it's really just a simple, repeatable feedback loop. This guide walks through exactly how to dial in a coffee grinder for espresso, step by step, so you're not left guessing every time you open a new bag.

The quick answer

Dialling in means adjusting your grind size, dose and shot time until your espresso extracts within a target window, typically around 25–30 seconds for a roughly 1:2 ratio of ground coffee to liquid espresso. Start with your grinder's recommended espresso setting, pull a shot, taste it, and adjust grind size finer or coarser based on both the timing and the flavour, one change at a time.

What "Dialling In" Actually Means

Every new bag of beans, and sometimes even the same bag as it ages, behaves slightly differently at the same grind setting, because factors like roast level, bean density and freshness all affect how quickly water flows through the puck. Dialling in is simply the process of finding the specific grind setting and recipe that extracts a particular coffee well, rather than assuming yesterday's setting will automatically work today.

Setting Your Dose

Start by deciding your dose — the weight of ground coffee in the portafilter basket, typically somewhere between 18–20g for a standard double basket, though this varies by basket size. Weighing your dose on a small set of scales removes one major variable before you even start adjusting grind size, since an inconsistent dose makes it much harder to diagnose whether a bad shot is a dose problem or a grind problem.

Setting Your Grind Size: Where to Start

Begin with your grinder's suggested espresso setting if it has one, or a noticeably fine grind similar in texture to table salt or slightly finer. This is a starting point, not a final answer — from here, you'll adjust based on how your shot actually pours and tastes. Our grind size guide covers where espresso sits relative to other brewing methods if you want more context.

Timing Your Shot

Start your timer the moment water first touches the coffee, and stop it when you've reached your target yield in the cup, typically around double the dry dose weight for a standard double shot — roughly 36–40g of liquid espresso from an 18–20g dose. A shot finishing in around 25–30 seconds is a widely used starting benchmark, though it varies somewhat by machine, bean and personal preference. Our guide to espresso extraction explains dose, time and yield in more depth.

Reading the Pour: Too Fast or Too Slow

How your shot pours tells you almost as much as how it tastes. A shot that finishes well under your target time, often thin and pale, is usually pouring too fast, covered in our guide to fast-pouring espresso. A shot that finishes well over your target time, sometimes stalling or spurting unevenly, is usually pouring too slowly, covered in our guide to slow-pouring espresso. Both point primarily to grind size as the fix.

Tasting and Adjusting

Timing gets you close, but taste is the real test. A shot that tastes sharp, sour or thin, even at the right time, usually needs a finer grind to slow the flow and extract more fully. A shot that tastes bitter, harsh or overly heavy, even at the right time, usually needs a coarser grind to speed the flow and pull back on extraction. Make small adjustments — a small twist of your grinder's dial — and re-test rather than making large jumps that overshoot the target.

The Dial-In Process, Step by Step

Weigh your dose, grind at your chosen setting, tamp evenly, and pull a shot while timing it and weighing your yield. Taste the result. If it's sour and finished quickly, go finer and try again. If it's bitter and finished slowly, go coarser and try again. If it tastes reasonably balanced but the timing is off, small adjustments to dose or yield can fine-tune it further. Repeat this loop, changing one variable at a time, until the shot tastes balanced within your target time window.

Puck Preparation and Even Distribution

Grind size and dose only matter if the resulting puck is evenly prepared, since channelling — water forcing an uneven path through weak spots in the puck — can undermine an otherwise well-dialled-in grind setting. Distribute the ground coffee evenly in the basket before tamping, whether with a dedicated distribution tool, a light shake, or simply careful attention as you fill it, and tamp level and firmly rather than at an angle. An uneven or angled tamp is a common, easily overlooked cause of an espresso shot that pours unevenly on one side of the portafilter, regardless of how carefully the grind size has been dialled in.

Adjusting for Different Basket Sizes

Baskets are generally labelled by the dose they're designed for — single, double or triple — and using a dose significantly different from what your basket is designed for can produce inconsistent results even at a correctly dialled-in grind setting. A double basket designed for 18g will generally struggle to distribute water evenly with only 14g of coffee in it, since the puck won't fill the basket properly. If you're dialling in a new basket size, treat it as a fresh dial-in process rather than assuming your previous grind setting will transfer directly.

Common Dial-In Mistakes

The most common mistake is changing grind size and dose at the same time, which makes it impossible to know which change actually caused the difference in your next shot. Another is making dramatic grind adjustments rather than small, incremental ones, which tends to overshoot from one extreme to the other rather than converging on the right setting. A third is dialling in with beans that are unusually fresh (within a day or two of roasting) or noticeably stale, both of which can behave inconsistently regardless of grind setting.

How Bean Freshness Affects Dialling In

Freshly roasted beans release carbon dioxide gas for some time after roasting, and very fresh beans can pour inconsistently or produce excessive crema that makes timing and yield harder to judge accurately. Beans that are a week or two past roasting tend to behave more predictably and are generally easier to dial in consistently. If your dial-in session is producing erratic, hard-to-reproduce results, checking your beans' roast date is worth doing before assuming your technique is at fault.

Why Grinder Quality and Consistency Matter

A grinder that produces an even, consistent particle size makes dialling in dramatically easier, since inconsistent particles extract at different rates within the same shot, making it harder to find a setting that tastes balanced. Espresso is particularly sensitive to this compared with other brewing methods, since its short extraction time leaves little room to compensate for uneven grinding. A dedicated espresso grinder with stepless or fine-stepped adjustment gives you much finer control than a general-purpose grinder shared across multiple brewing methods.

Which Amici Coffee Is a Good Starting Point for Dialling In?

Our Amici House Roast, with its smooth, chocolatey, lower-acidity profile, is a genuinely forgiving coffee to practise dialling in with, since it tends to taste reasonably good across a slightly wider grind range than brighter, more delicate origins. Once you're comfortable with the process, our full comparison of all six coffees can help you find your next espresso bean to dial in.

Keep Fresh Coffee Coming

Since bean freshness has such a direct effect on dialling in specifically, keeping a steady supply of recently roasted beans makes the whole process easier and more predictable. Our coffee subscription lets you choose your beans, your grind and your delivery frequency, so fresh coffee keeps arriving exactly when you need it.

Why Choose Amici Coffee?

Amici Coffee is an independent UK coffee business with six carefully selected single origin coffees, each with clear origin and tasting information rather than vague blend descriptions. Beans are roasted in partnership with a certified B Corp speciality coffee roasting partner that holds the highest B Corp score of any coffee roaster we work with — a genuinely world-leading, global leader in ethical coffee roasting. You can order online for delivery, visit our café in person, or set up a subscription so your coffee never runs out.

Frequently Asked Questions

What does "dialling in" espresso actually mean?
Adjusting your grind size, dose and shot time until a specific coffee extracts in a balanced, good-tasting way, since the right setting varies by bean and freshness.

How long should an espresso shot take to pour?
Roughly 25–30 seconds is a common starting benchmark, though this varies by machine, bean and personal taste preference.

Should I change grind size or dose first when dialling in?
Grind size is usually the primary lever, since it directly controls flow rate. Adjust dose separately and one variable at a time.

Why does my dial-in keep changing even with the same beans?
Bean freshness changes over time, environmental humidity can shift slightly day to day, and small inconsistencies in dose or tamping can all affect results, particularly early in the bag's life.

Do I need an expensive grinder to dial in espresso properly?
A grinder capable of fine, consistent adjustment specifically suited to espresso makes the process considerably easier, though the core dial-in principles apply regardless of grinder price.

How often do I need to re-dial in my grinder?
Whenever you open a new bag of beans, and sometimes partway through a bag as the beans age, since both roast and freshness affect how a coffee extracts.

Does the weather or humidity affect dialling in?
Yes, to a small degree. Humidity can affect how coffee grounds behave and how quickly beans absorb moisture from the air, which is part of why baristas sometimes make small grind adjustments through the day even with the same bag of beans.

The Bottom Line

Dialling in isn't guesswork once you understand the loop: adjust grind size based on timing and taste, change one variable at a time, and use fresh, rested beans for the most predictable results. With a bit of practice, it becomes a quick, routine part of opening a new bag rather than a frustrating puzzle.

Explore Amici's range of single origin coffees, or set up a regular delivery so fresh coffee keeps arriving.