Every bag of coffee arrives with a question attached: at what grind, ratio and temperature does this coffee taste its best on your grinder and your machine? Dialing in is how you answer it - pulling a short series of shots, tasting each one and changing a single variable until the cup is balanced. It is not a talent and it is not luck. It is a method, and once you follow it the same way every time, a new bag goes from "something's off" to a shot you are happy with in three to six attempts.
Why Every Bag Needs Dialing In
There is no universally correct setting. Two coffees at the same roast level can need very different grinds, and the same coffee needs a different setting on a different grinder - grinder dials are reference marks, not a shared language, so someone else's "setting 12" tells you almost nothing. Espresso is also the fussiest of all the brewing methods: strength, body and balance only line up inside a narrow band of grind and ratio.
And the target moves. As beans rest and age, the way they grind and release gas changes, so a recipe that was perfect on day ten can run fast and taste thin by week four. Dialing in is not something you do once per coffee; it is something you do at the start of every bag and touch up as the bag goes on.
The Method at a Glance
- Start from a sensible recipe - 18 g in, 36 g out, at the grind you used for your last similar coffee.
- Lock the dose - it stays fixed for the whole session.
- Treat the first shot as a measurement - taste it, but expect it to be off.
- Grind to get the flow into the right window - roughly 25-35 seconds for a medium roast.
- Tune the ratio by taste - move the yield 2-4 g at a time.
- Hone the grind and adjust temperature last - small steps, one at a time.
- Confirm with a repeat shot, then save the recipe - and re-check it as the bag ages.
The rest of this guide explains each step, shows a complete dial-in session shot by shot, and covers the situations where the standard advice breaks down.
Before the First Shot
Four things make or break a dial-in session before you pull a single shot:
- Rested beans. Coffee that is too fresh is still releasing a lot of carbon dioxide, which makes shots erratic - dialing it in on day three means re-dialing it on day ten. As a rough guide, give dark roasts about a week and medium roasts one to two weeks before you commit to a recipe; light roasts often need longer. The details are in our coffee freshness guide.
- Sensible water. Very hard or very soft water shifts extraction, and a recipe dialed in on one water will not transfer to another. See water for espresso.
- A warm machine. The first shot on a half-warm group tastes sour for reasons no grind change will fix.
- Enough coffee. Budget three to six doses - roughly 60 to 110 g - for a first dial-in. The missed shots are not wasted: drink them as Americanos or in milk, and taste every one of them, even the obvious failures. Each one tells you something.
The Method, Step by Step
Step 1: Start from a sensible recipe
Begin with the modern default for a double shot: 18 g in, 36 g out (a 1:2 ratio), with the timer started when you start the pump. Use roughly 93 °C for a medium roast, a degree or two higher for light roasts and a few degrees lower for dark ones - the temperature and pressure guide explains why.
For the grind, start where your last similar coffee ended up. If this is a re-buy of the same coffee, begin at the old setting, or one step finer if the new bag is fresher. If you have no reference at all, Scott Rao's advice is worth following: start on the coarse side. A shot that runs too fast is still drinkable and its speed tells you clearly how much finer to go; a shot ground far too fine clogs, channels and tastes harsh, and teaches you much less.
Step 2: Lock the dose
Choose a dose that suits your basket - an 18 g basket takes roughly 17-19 g - and keep it identical for the whole session, weighed to 0.1 g. The dose is your anchor. If it drifts, every change in flow and taste is ambiguous: was it the grind, or was it the extra half gram? The only times to move the dose are covered further down: fine-tuning between the steps of a stepped grinder, and adding strength for milk drinks.
Step 3: Treat the first shot as a measurement
Pull the first shot exactly as planned, stop it on weight, and write down three things: the time, what the flow looked like and how it tasted - stirred first, because an unstirred shot only lets you taste one layer. Do not expect it to be good. Its job is to tell you where you are.
Step 4: Grind to get the flow into the window
If the shot ran very fast or very slow, fix that first, with the grinder. For a medium roast at 1:2, roughly 25-35 seconds is the window to aim for. Treat it as a way of getting into the right neighbourhood, not as a finish line: light roasts often taste best well beyond 35 seconds, and good shots outside the classic 25-30 seconds are common.
- Way too fast (under about 20 s, thin, sour): grind finer.
- Way too slow (over about 40 s, dark drips, harsh): grind coarser.
- Step size: one click on a stepped grinder; about a quarter to half a number on a stepless dial. Big jumps overshoot.
- Purge after every change if your grinder retains coffee, so the next shot is actually ground at the new setting.
How far one step moves the time depends entirely on your grinder, which is why the first two or three shots of your first bag are also a lesson in how your grinder behaves. Note it down: next time you will know that one click is worth, say, four seconds. Why grind has such a strong grip on flow is explained in the grind size guide.
Step 5: Tune the ratio by taste
Once the flow is roughly in the window, stop chasing the timer and start listening to the cup. From here the most effective lever is usually the yield, because changing it needs no grinder adjustment and no purge.
- Sour, sharp, thin finish - under-extracted: pull longer, for example from 36 g to 40 g, then to 44 g.
- Bitter, harsh, drying - over-extracted: pull shorter, for example 32 g.
- Balanced but weak or watery: pull shorter, or add half a gram to a gram of dose.
- Balanced but overwhelming: pull longer.
Moving the yield does two things at once: a longer shot is both weaker and more extracted, a shorter one stronger and less extracted. That is the idea behind the espresso compass, and it is why the ratio is such a powerful tuning tool. Move in steps of 2 to 4 g - smaller changes are hard to taste, larger ones overshoot. The maths of ratios is covered in brew ratios explained.
Some baristas, Lance Hedrick among them, lean on the ratio even harder: when a light roast tastes sour, they often grind a little coarser and pull a much longer shot rather than grinding finer. Both approaches work. The rule that matters is the same in both: one change per shot.
Step 6: Hone the grind, then touch temperature
When the shot tastes good, find out whether it can taste better. Go one small step finer at the same ratio. If the cup gets sweeter and fuller, keep going; the moment it turns harsh, drying or muddy, go back one step. That last good setting is the top of your window. Espresso Aficionados describe the goal neatly: grind as fine as you can while still getting a tasty, balanced shot.
Temperature comes last, in steps of 1 to 2 °C: a little hotter if the shot is balanced but still slightly sharp, a little cooler if it is balanced but has a bitter edge. Tasting tests disagree about how much a degree or two changes the cup, but everyone agrees the effect is smaller than grind and ratio - which is exactly why you adjust it last. If your machine offers pre-infusion or pressure control, that is a final refinement, not a starting point.
Step 7: Know when to stop, confirm and save
You are done when three things are true: the shot is balanced - pleasant acidity, clear sweetness and no drying astringency; one step either way on the grind or the yield makes it worse; and a repeat shot with the same recipe tastes the same. That repeat matters: one great shot can be luck, two in a row is a recipe.
Write the recipe down with the coffee's name and roast date: dose, yield, time, grind setting and temperature. The next bag of the same coffee then starts from an answer instead of from zero, and usually needs only one or two adjustments.
A Complete Dial-In Session, Shot by Shot
Here is what a typical session with a new bag of medium-roast coffee looks like. The numbers are illustrative, but the pattern is the one you will see again and again.
| Shot | Recipe | Taste | Decision |
|---|---|---|---|
| 1 | 18 g in, 36 g out, 18 s, grind from the last bag | Thin, sour, short finish | Far too fast - one step finer |
| 2 | 18 g in, 36 g out, 27 s | Sweeter, but still a sharp edge | Flow is in the window - lengthen the yield |
| 3 | 18 g in, 40 g out, 30 s | Balanced, a little light in body | Hone: one small step finer |
| 4 | 18 g in, 40 g out, 33 s | Sweet, fuller, clean finish | Test the top of the window: one more step finer |
| 5 | 18 g in, 40 g out, 37 s | Heavier, drying finish | Too far - go back to shot 4's setting, repeat it to confirm, save |
Notice the rhythm: the grinder fixes the flow, the yield fixes the taste, and the last shots find the edge of the window from both sides. Light roasts follow the same pattern with different numbers. La Marzocco's guide to dialing in a modern light roast, for example, starts at 17 g in and 34 g out in about 55 seconds - intense and sharp - then goes coarser and finally lands on a 1:3 ratio, 51 g out in about 45 seconds.
Reading the Cup: What to Change Next
| What you taste and see | Likely cause | One change for the next shot |
|---|---|---|
| Sour, thin, fast shot | Under-extracted, ground too coarse | One step finer |
| Sour, but the time is already in the window | Under-extracted | Longer yield, +2 to 4 g |
| Bitter, harsh, slow shot | Over-extracted | Shorter yield, or one step coarser |
| Balanced but weak and watery | Strength too low | Shorter yield, or +0.5 to 1 g dose |
| Balanced but overwhelming | Strength too high | Longer yield |
| Drying, astringent, slow | Ground too fine to flow evenly | Coarser - and check the puck prep |
| Sour and bitter at the same time | Uneven extraction, channeling | Fix the prep, not the grind: dry basket, RDT, WDT and a level tamp |
Two habits make this table far more reliable: stir the shot before tasting, and taste it once it has cooled slightly. For the reasoning behind each row, see the sour and bitter troubleshooting guide and the science of extraction. If you would rather not work it out by hand, the dialing tool takes the numbers and the taste and returns exactly one change - you can even open it with the symptom sour, bitter or sour and bitter at once already selected.
Dialing In Light, Medium and Dark Roasts
| Light | Medium | Dark | |
|---|---|---|---|
| Starting temperature | 93-96 °C | about 93 °C | 88-92 °C; start lower for very dark roasts |
| Ratio | 1:2 to 1:3 | about 1:2 | 1:1.5 to 1:2 |
| Time | Often 35-55 s, and that is fine | 25-35 s | Often shorter |
| Grind | Fine - these beans are dense and less soluble | Middle of your range | Coarser |
| Most common problem | Sourness; grinding ever finer until the shot channels and turns sour and bitter at once | Rarely extreme - the forgiving middle | Bitterness and ashy, drying notes from over-extraction |
For light roasts, the longer ratio is usually a better tool than an ever-finer grind, and a slightly lower dose (16-18 g) can help. For dark roasts, pull shorter and cooler, and if your machine allows lower pressure - around 6 bar - it often softens the bitterness. Dark beans are also less dense, so the same weight takes up more room in the basket: check that there is still space above the puck.
Dialing In for Milk Drinks
Milk mutes acidity and bitterness and amplifies sweetness, so a shot that is slightly sharp on its own can be lovely in a flat white, and a shot that is perfect straight can disappear in a large latte. If most of your coffee goes into milk, taste your test shots in milk. When the coffee gets lost, add strength - a gram more dose or a slightly shorter ratio - rather than simply cutting the shot short: a badly under-extracted shot tastes thin and sour in milk too. And if you pull singles for smaller drinks, read single vs double shots first: singles are much harder to dial in.
When Your Equipment Sets the Limits
- Pressurised baskets. Dual-wall baskets create resistance with a single small exit hole, so they hide grind problems instead of revealing them. The time, the crema and the flow tell you very little, and there is not much to dial in. If you want to dial in properly, switch to a standard basket; the espresso machine buying guide explains the difference.
- Stepped grinders with big steps. If one click moves the shot time by several seconds or more, use the grinder for coarse adjustment and the dose or yield for the fine tuning in between: plus or minus half a gram to a gram of dose, or a couple of grams of yield. If you keep landing between clicks, that is the strongest case for a grinder upgrade - see our gear recommendations.
- Grinder numbers do not transfer. Two grinders of the same model can have zero points many clicks apart, and a grinder's own zero can shift after cleaning. Use other people's settings as a rough hint at most.
- The first shot of the day. Retained grounds from yesterday and a grinder that has been sitting cold both nudge the first shot. Purge a little, and do not re-dial on the evidence of one morning shot.
- Temperature stability. A machine that swings several degrees from shot to shot makes dialing in feel random. Warm up properly and, on heat-exchanger machines, use a consistent cooling flush - both are covered in the espresso workflow.
Keeping a Bag Dialed In as It Ages
A recipe is only correct for the coffee as it was when you dialed it in. The most common pattern as a bag moves through weeks two to five is that shots gradually run faster and taste thinner, and the fix is to grind a little finer - often a step every few days. Treat that as a tendency rather than a law: very fresh coffee can behave the other way, which is one more reason not to lock in a recipe during the first few days.
- Check, do not assume. When a shot runs a few seconds faster than your recipe, taste it before changing anything. If it still tastes right, leave it.
- Frozen beans grind finer. Colder beans fracture into smaller particles, so dial in with the beans in the state you will actually use them, and do not mix frozen and room-temperature beans on one setting.
- Same coffee, new bag. Roast batches differ slightly, and the new bag will be at a different age. Start from the saved recipe and expect one or two small corrections.
Do You Need a Refractometer?
No - but it is the only way to put a number on extraction. A refractometer measures the strength of the shot as TDS (total dissolved solids), and from that you can calculate the extraction yield:
Example: 18 g in, 36 g out, TDS 10% → 10 × 36 ÷ 18 = 20% extraction.
Typical espresso lands around 8-12% TDS and 18-22% extraction; modern light-roast shots at long ratios often extract considerably more. Two cautions if you buy one. Stir the shot and filter the sample, because unfiltered espresso reads high - Jonathan Gagné measured the error at about 0.4% TDS, and it varies too much to correct for. And remember that the number does not taste the coffee for you: two shots with the same extraction yield can taste quite different. Taste decides; the refractometer only explains.
The Mistakes That Make Dialing In Take Forever
Dialing In With Dial Your Shot
This whole method is what the Dial Your Shot dialing tool is built around. You enter the real numbers of the shot you just pulled - dose, yield, time, grind setting and temperature - describe the taste, and it returns one prioritised change with the reasoning behind it. That is steps 4 to 6 of this guide, one shot at a time.
- Bags keep the answer. Sign in (it is free) and press Dial in a new bag when you open a coffee. The bag starts from your last good recipe, and when a shot is right you press This one's good to save it - so the next bag begins where this one ended.
- See the moves. The interactive Espresso Compass shows where your shot sits and which single lever moves it toward balance.
- Practise without beans. Dial It In, our espresso training game, runs the same diagnosis on simulated shots, so you can build the habit before you spend a bag learning it.