How to set up an espresso grinder step by step

Setting up an espresso grinder comes down to one rule: establish a fixed dose and target yield, and then change only the grind size until the espresso flows in the intended time and tastes good. If the brew is sour and flows too quickly, grind finer. If it is bitter and flows too slowly, grind coarser.

It sounds simple, but in practice, many people change several things at once and lose control over what actually improved the taste. Below we show how to set the coffee grind size step by step, how to recognize mistakes by taste, and when the calibration needs to be repeated.

Why grinding coffee for espresso is so important

In espresso, water under approx. 9 bar pressure flows through a compressed layer of coffee in a few dozen seconds. The grind size determines how much resistance this layer offers, and therefore how quickly the water flows and how many substances it manages to dissolve.

Finer grinding means a larger contact surface and slower flow. Coarser grinding gives a faster flow and weaker extraction. A study published in Scientific Reports in 2024 showed that the flow rate is strongly influenced by the proportion of the finest particles (so-called fines, below 100 µm), whose amount also depends on the grinder design.

There is one more trap. A study by Cameron and colleagues (journal Matter, 2020) showed that grinding too fine does not increase extraction indefinitely. Above a certain limit, water starts to flow unevenly, choosing channels in the coffee, and extraction and repeatability drop. Therefore, “the finer, the stronger” is a myth: the goal is a grind size at which the espresso extracts evenly.

Before you start: what to prepare

Calibration only makes sense when the other variables are under control. Prepare:

• Freshly roasted coffee beans for espresso, e.g. Super Tuscan or Milk & Butter. You calibrate on one package, you work on it.

• A scale with 0.1 g accuracy, preferably with a timer. You will find them in the category coffee scales.

• A preheated espresso machine. The portafilter and group should have a constant temperature before you brew the first espresso.

• A starting recipe. For our espresso blends, it is 16–18 g of coffee and approx. 45 ml of drink in 25–27 seconds for a double shot. You will find the exact dose for a given coffee on its product page.

• A piece of paper or notes on your phone. Write down the grinder setting, dose, yield, time, and a short taste assessment.

For calibration, you usually need 3–5 espressos, so prepare approx. 100 g of coffee.

Setting up an espresso grinder step by step

1. Establish the dose and do not change it. Choose, e.g., 18 g and stick to it throughout the calibration. If you change the dose and grind at the same time, you will not know what worked.

2. Choose a starting point. Set the grinder in the range intended for espresso according to the manufacturer's instructions. With a new grinder, it is better to start slightly too coarse than too fine, so as not to “choke” the espresso machine.

3. Clean the grinder after changing the setting. Some coffee ground at the previous setting remains in the grinder channels. After every change, grind and throw away a small portion before weighing the dose for measurement.

4. Brew and measure. Distribute the coffee evenly in the basket, tamp it with moderate pressure, and place the cup on the scale. Measure the yield and the time from starting the pump.

5. Compare the result with the target. If you achieve the target yield significantly faster than in 25 seconds, grind finer. If significantly slower than in 27–30 seconds, grind coarser.

6. Change in small steps. One change at a time and always by the smallest possible step. With stepless grinders, this is often a fraction of a turn of the knob.

7. Try it. Time and weight are only a guide. If the espresso is within the parameters but is slightly sour, grind minimally finer; if bitter and drying, minimally coarser. The ultimate criterion is your taste.

8. Write down the setting. When you hit the right taste, note down the grinder position for this coffee. For the next package, you will start the calibration from a ready-made point.

Remember that the recipe on the product page is a starting point, not a dogma. Some prefer shorter and denser espresso, others longer and lighter. Adjust the yield to yourself, but change it only after the grind is already set.

How to recognize bad grinding by taste

The taste of espresso says a lot about what happened in the portafilter. Sourness without sweetness is usually under-extraction, bitterness and astringency are over-extraction.

If despite a well-set grinder the espresso remains bitter, also check the cleanliness of the machine and the water temperature. We describe more causes in the article Why coffee can taste bitter.

When to set the grinder again

Grinder setting is not a one-time thing. It is worth repeating the calibration when:

• you change the coffee. Different origins, processing methods, and roast levels behave differently in the grinder. Dark roasted coffee usually requires a different setting than light roasted coffee.

• you open a new edition of the blend. Our blends are seasonal: the character remains the same, but the bean composition changes with fresh harvests. After changing the edition, check the brewing time.

• the coffee ages. With each week after roasting, the beans release CO₂ and change, so the espresso often starts flowing faster. Then you usually need to grind a little finer.

• you change the dose or basket. A different amount of coffee means a different resistance for the water.

• after cleaning or replacing the burrs. Even at the same knob position, the grinder may grind slightly differently.

A good practice is a quick check of the first espresso every day: weigh the yield, check the time, and try it. If everything is correct, you don't change anything.

Grinder, coffee, and knowledge: what you will find at LaCava

What espresso grinder?

For espresso, a burr grinder with precise adjustment in the fine grind range is needed. The more settings in this range (or stepless adjustment), the easier it is to hit the right brewing time. Grinders with several adjustment steps work better for pour-over methods.

In our category coffee grinders for espresso and pour-over methods include, among others:

If you are looking for a solution for a cafe or office where the grinder works all day, talk to us about working with cafes. We select equipment for the scale of work and calibrate it together with the team.

Coffee for calibration

To start, choose coffee with a predictable, chocolatey profile and low acidity. It is then easier to distinguish over-extraction from under-extraction. These will work well: Super Tuscan, Milk & Butter and Deep Focus. Once you master grinder setting, reach for more demanding single origin pod espresso.

Training

Calibration is learned fastest in practice, under the supervision of a trainer. In our Training Center at the roastery, we conduct the SCA Barista Skills Foundation course and the proprietary Barista Fundamentals training.

Sources

1. Cameron M.I., Morisco D., Hofstetter D., Uman E., Wilkinson J., Kennedy Z.C., Fontenot S.A., Lee W.T., Hendon C.H., Foster J.M. (2020). Systematically Improving Espresso: Insights from Mathematical Modeling and Experiment. Matter, 2(3), 631–648. doi:10.1016/j.matt.2019.12.019

2. The role of fines in espresso extraction dynamics (2024). Scientific Reports. doi:10.1038/s41598-024-55831-x

3. LaCava: product pages Super Tuscan and Milk & Butter (espresso recipes) and grinders Melitta Calibra and Baratza Encore, as of October 2026.