Espresso Dial-in Without a Stopwatch – The CCC Method

Most dial-in guides tell you your espresso should run for 25 to 30 seconds, and that you should turn the grind adjustment until it does. We don't run a stopwatch at all – and grind size isn't the fine-tuning knob either. We take it once to the extraction maximum, leave it there, and adjust from then on through the dose.

That sounds like heresy at first. But it's exactly what one of the most-cited scientific papers on espresso recommends. In this article we explain how we dial in at Coffee Coaching Club, why we do it this way – and where the research sets us a clear limit that we take seriously.

And as always with us: this is our method, not the law. If you're happy with a stopwatch, your cup is not one bit worse for it.

What does dial-in mean for espresso?

Dial-in means adjusting a new bean on the grinder and in the recipe until the espresso tastes right. At its core, you change three things: the coffee dose weighed in, the espresso amount dispensed, and the grind size. Everything else – temperature, pressure, brew time – is either fixed or falls into place on its own.

The reason dial-in is necessary at all: every bean behaves differently. Roast level, age, density and processing change how quickly the water runs through and how easily the aromas release. A setting that was perfect for the last bag can be completely off for the new one.

Our method runs in two stages: first the grind to the maximum, then the dose as the fine adjustment. Both are described in detail below.

Why do we leave the stopwatch out of dial-in?

Because time in espresso is a result, not a control. It tells you afterward how the coffee bed behaved – but you can't set it directly, only indirectly through the grind. If you steer toward a number of seconds, you're optimizing for a measurement instead of for taste.

We didn't invent this stance ourselves. A research team around Michael Cameron and Christopher Hendon published a mathematical model of espresso extraction in 2020 in the journal Matter and tested it experimentally. The authors' recommendation is unambiguous.

In other words: leave out the brew time and control the extraction yield solely through the mass of coffee and the mass of water. That's exactly what we do – for us, the mass of coffee is even the more important of the two levers. The same paper also suspects that the widespread 20-to-30-second guideline is partly responsible for many baristas working with grind settings where the coffee bed partially clogs and channels unevenly.

What ratio do we use – and why only double shots?

We usually stay between 1:1.5 and 1:2 – so 16 grams of coffee to 24 to 32 grams of espresso. That's shorter than the often-cited standard of 1:2 and produces a denser, more syrupy cup. This is controlled exclusively through the scale: coffee weighed in versus espresso dispensed, both in grams.

The short ratio is directly connected to our fine grind. Less water dissolves less at the same grind size – so if you pull short, you have to grind finer to reach the same extraction yield. Our two decisions aren't two separate preferences, then, but two halves of the same decision.

For context: the standard recipe in the Cameron et al. study was 20 grams of coffee to 40 grams of beverage, so 1:2. We're below that on average. What matters is that output is measured by weight, not by eye: espresso foams, the crema deceives, and two visually equal-looking cups can differ by several grams. Without a scale under the cup this method simply doesn't work.

We pull exclusively double shots, and the reason is arithmetic. The same absolute inaccuracy in weighing or in stopping the output weighs twice as heavily on a small dose as on a large one. Because for us the dose is the fine-tuning tool, a single basket would be a particularly poor choice: we'd be turning the very dial that's the least precise there. On top of that, a shallow coffee bed offers the water less resistance, and channels break through faster.

We don't know of a peer-reviewed study on the advantage of the double shot over the single – the math on the relative dosing error holds up, the argument about bed geometry is experience gained from everyday life behind the machine.

Why do we dose between 14 and 18 grams?

14 to 18 grams isn't a range of convenience for us, it's the working range of our fine-tuning tool. Because the grind is at its maximum after stage one and stays there, the dose is the size we turn afterward – in small steps, within these four grams.

The limits come from physics: at the low end, the relative dosing error limits the range, at the high end, the space in the basket does. If the bed is too high, the water has too little room at the top, and the puck gets pressed against the brew group during the shot.

That the dose really is a genuine lever and not just a quantity is shown by the same Cameron et al. study: 15 instead of 20 grams only landed back on the same extraction yield once the grind was adjusted. Changing the dose shifts you within the extraction landscape – that's exactly what we use. A café that reduced its dose by 25 percent saved, according to the authors, 0.13 US dollars per drink along the way, projected to 3'620 US dollars a year.

Honestly noted: in the study, the smaller dose went together with a coarser grind, not a finer one. The finding confirms that the dose is an effective lever – not automatically our choice of grind.

How fine do we grind – and where's the limit?

We grind fine, right up to the extraction maximum. Grinding finer means more surface area, more resistance and more dissolved substance – and because we don't have to steer toward a brew time, we can go finer than someone who wants their shot done in 25 seconds. Together with our short ratio, this only then adds up to a coherent picture: little water needs a lot of surface area.

But there's a point where it tips, and we take that seriously. The same Cameron et al. work found a maximum: extraction yield rises with a finer grind – up to a peak. After that it falls again, because parts of the coffee bed clog and the water finds channels. The authors speak of “inhomogeneous flow […] resulting in poor reproducibility and wasted raw material.”

This is how we understand “grind very fine”: not as “always finer”, but as “as fine as possible without shooting past the maximum.” The maximum is the guardrail, not the enemy. Anyone working without a stopwatch gets closer to this point – and therefore needs to know it all the better.

And once it's found, it stays put. That's the real difference from the usual approach: for us, the grind isn't a dial that gets constantly turned during daily operation, it's a setting determined once per bean. Fine-tuning after that happens through the dose.

For context: in the study, the peak was at a specific dial number on a Mahlkönig EK 43. That number doesn't transfer to any other grinder. Where your maximum lies, you have to find out on your own grinder – and it shifts if you change the ratio.

Besides fineness, uniformity counts too. A study by Uman and colleagues in Scientific Reports showed that colder beans not only produce smaller particles, but also a narrower distribution – between room temperature and −196 °C, the most common particle diameter dropped by 31 percent, with the biggest jump already happening between room temperature and −19 °C. The authors conclude that the higher uniformity mainly prevents bean material from ending up unextracted in the waste.

How do you find your own yield maximum?

This is stage one, and it runs through the grind: hold the dose and output amount fixed and only change the grind – step by step, finer. As long as the espresso gets sweeter, denser and rounder with every step, you're on the rising branch. As soon as it becomes hollow, harsh, or varies from shot to shot, you're past the peak. Then you go back one step – and leave the grinder alone.

If you want to measure instead of taste, you need a refractometer. The extraction yield is calculated like this: yield in percent equals TDS in percent times beverage mass in grams divided by coffee mass in grams. At 16 grams of coffee, 32 grams of espresso and 10 percent TDS, that would be 20 percent. Measuring devices for this are available at Apax Lab.

But the decisive signal isn't the peak value, it's the spread. If three shots in a row taste distinctly different even though you changed nothing, the grind is too fine – regardless of how good the best of those three shots was.

How do you then fine-tune through the dose?

This is stage two. The grind is set, and from now on you only change the dose – in half-gram steps, within 14 to 18 grams. The advantage: you can always get back exactly to where it tasted right, because a number on the scale is unambiguous, a position on the grind wheel often isn't.

Path A: the ratio stays, the output moves with it. 16 to 32 grams becomes 17 to 34 grams. The strength in the cup stays similar, but the bed gets deeper, resistance rises, and the water needs longer to pass through the same amount of ground coffee. This is the path when the character of the cup suits you and you just want the extraction to be rounder.

Path B: the output stays, the ratio shifts. 16 to 32 grams becomes 17 to 32 grams, so 1:1.9. This directly shifts concentration and yield: more coffee for the same amount of drink gives a denser, more concentrated cup. This is the path when the cup seems too thin or too unfocused to you.

Which one we choose, we decide case by case – based on what the cup is missing right now. What matters is only that you stick to one path per round, otherwise you won't know in the end which of the two changes had the effect.

How do you dial in step by step?

What to do when the espresso channels?

Channeling means the water carves a path of least resistance through the puck instead of flowing evenly through the whole bed. Part of the coffee gets over-extracted, the rest stays under-extracted – and the cup tastes bitter and thin at the same time. It's recognizable from spraying jets, holes in the puck, and the fact that two identically prepared shots taste different.

Turning up the pressure barely helps here. A paper by Waszkiewicz and colleagues, published in 2026 in Physics of Fluids shows that at the usual 6 to 9 bar, the coffee bed behaves after about 30 to 40 seconds like a poroelastic material: it gives way, compacts – and the flow no longer keeps rising when pressure is increased. The authors trace part of the channeling and the shot-to-shot variation directly back to this.

What actually helps is puck preparation: break up clumps with a WDT tool then distribute evenly and tamp level with a precision tamper before using a well-made basket – why that matters is covered in our article on IMS precision baskets. The right tools are available at Normcore and in Barista Equipment.

What does a spritz of water before grinding do?

A fine spray of water on the beans before grinding – known in the scene as the Ross Droplet Technique – reduces static charge and thus clumping in the grounds. This isn't a kitchen trick, but the subject of a paper by Méndez Harper and colleagues, which appeared in 2023 in Matter as well.

The authors found that fewer clumps produce a more densely packed coffee bed, that the water consequently flows through more slowly, and that the concentration of the finished espresso rises by up to 15 percent for the same dry coffee amount. Christopher Hendon sums it up: raising concentration by 10 to 15 percent for the same dose has major consequences for cost and quality. Shot-to-shot repeatability also improved.

For us, this is the natural partner to fine grinding: the finer you grind, the more the grounds charge up and the more clumps form – exactly where the effect pays off most. And because we fine-tune through the dose, anything that reduces the spread between two identical doses helps.

The paper doesn't state a universally valid amount of water. In practice, a single fine spritz on the weighed beans is enough; more water doesn't belong in a grinder.

What does this mean for you at home?

No professional equipment is needed for this, just two things: a scale that displays fast enough, and a grinder with fine adjustment steps. Everything else is practice. A single-dose grinder fits this method especially well, because with every shot you grind exactly the amount you weighed in – and for us, the dose is the size that matters.

And then what always applies with us applies here too: this is our method because it delivers the most reliable cups for us. If your espresso tastes better with a stopwatch, with a single basket, or with a completely different ratio, then you're right and we have a method. United by Coffee.

If you'd rather go through this together at the machine once: in our showrooms in Bern and Zürich, that's exactly what we do – in the Barista Course in Zürich, in the Workshops or in a consultation appointment.

Frequently asked questions about espresso dial-in

Should I adjust the grind or the dose when dialing in?

For us, both – but one after the other. First you take the grind once to the extraction maximum and leave it there. After that you only fine-tune through the dose, in half-gram steps. The advantage: a number on the scale is unambiguously repeatable, a position on the grind wheel often isn't.

How long does an espresso have to run?

From our point of view, it doesn't have to run for a particular time at all. We control through dose and output amount in grams and let the brew time be what it is – a measurement. Cameron et al. explicitly recommend in Matter (2020) to ignore the brew time and control solely through the mass of coffee and water.

How much coffee goes into a double shot?

We work with 14 to 18 grams, and for us this range is the fine-tuning zone: because the grind stays put once it's set, the dose is the size we turn afterward. At the low end, the relative dosing error limits the range, at the high end, the space in the basket does.

What is the brew ratio for espresso?

The brew ratio is the amount of coffee weighed in relative to the amount of espresso dispensed, both in grams. We usually stay between 1:1.5 and 1:2; with a 16-gram dose that's 24 to 32 grams of espresso. Shorter becomes denser and more syrupy, longer becomes clearer and lighter.

Why does my espresso taste sour?

Usually it's under-extracted: the grind is too coarse, the water runs through too quickly, or the output amount is too small. Grind one step finer and leave the ratio unchanged. Not every acidity is a flaw, though – light roasts naturally bring fruity acidity with them.

What is channeling and how do I recognize it?

With channeling, the water seeks out paths of low resistance through the puck instead of flowing evenly through the bed. It's recognizable from spraying or uneven jets, craters in the knocked-out puck, and the fact that identically prepared shots taste different. The cause is almost always in puck preparation, not in the pressure.

Should I grind finer or coarser for espresso?

Finer increases extraction – but only up to a maximum. Cameron et al. found a peak beyond which yield and repeatability drop again because the bed clogs in places. We deliberately grind right up to this maximum, partly because our short ratio demands it – but we go back one step as soon as the shots start diverging.

How do I calculate the extraction yield?

Extraction yield in percent equals TDS in percent times beverage mass in grams divided by coffee mass in grams. The TDS value is measured with a refractometer. At 16 grams of coffee, 32 grams of espresso and 10 percent TDS, that gives a yield of 20 percent.

Sources

• M. I. Cameron, D. Morisco, D. Hofstetter, E. Uman, J. Wilkinson, Z. C. Kennedy, S. A. Fontenot, W. T. Lee, C. H. Hendon, J. M. Foster: Systematically Improving Espresso: Insights from Mathematical Modeling and Experiment. Matter 2 (2020) 631–648.
• J. Méndez Harper et al.: Moisture-controlled triboelectrification during coffee grinding. Matter (2023), DOI 10.1016/j.matt.2023.11.005.
• R. Waszkiewicz, F. Myck, Ł. Białas, M. Puciata-Mroczynska, M. Dzikowski, P. Szymczak, M. Lisicki: Under pressure: Poroelastic regulation of flow in espresso brewing. Physics of Fluids (2026), DOI 10.1063/5.0319611.
• E. Uman, M. Colonna-Dashwood et al.: The effect of bean origin and temperature on grinding roasted coffee. Scientific Reports 6 (2016) 24483.

If you want to apply the same thinking to filter coffee, you'll find it in our V60-Anleitung. And if you want to know what sets espresso, ristretto and lungo apart, we have separate articles about Espresso and the Ristretto.