The grind setting is the variable that most strongly influences your espresso—more than brewing temperature, more than tamp pressure, more than the machine. Nevertheless, "how fine do I need to grind?" is a question for which there is no universal answer. We explain why this is the case, how to find your ideal grind setting, and what you can do if it doesn't taste right. (You can find the basics of espresso preparation in our Preparation Guide.)
Why there's no single number
"Set your grinder to 12" is a phrase often seen in forums. The problem: setting 12 on your grinder yields a completely different particle size than setting 12 on a grinder of the same type. Even two identical grinders from the same factory can grind differently at the same setting. The burrs are seated slightly differently, calibration varies, and usage has worn the burrs differently.
Therefore, the grind setting is not a numerical value that you can transfer. It is a setting that you must find yourself for your grinder, your coffee, and your machine. The good news: it's less complicated than it sounds.
The Method: Finding the Right Grind Over Time
You need three things: a scale, a stopwatch (or a scale with a timer), and a recipe as a starting point. Let's use the standard recipe: 18g coffee, 36g espresso in the cup, extraction time 25–30 seconds.
Dose 18g of coffee, tamp, extract, and observe two things: how many grams end up in the cup and how long it takes. The extraction time tells you if the grind setting is correct.
If the espresso extracts too quickly (e.g., 36g in 18 seconds), the grind is too coarse. The water finds too little resistance and rushes through the coffee bed. The espresso will typically taste sour, thin, and watery.
If it extracts too slowly (e.g., 36g only after 40 seconds), the grind is too fine. The water can barely pass through, and the coffee is over-extracted. The espresso will taste bitter, astringent.
If you land within the time window (25–30 seconds for 36g), you are in the right range. From here, your taste decides.
Adjusting the Grind: How much to turn?
Here's the rule: less than you think. With most espresso grinders, small adjustments make a noticeable difference. On some grinders with fine adjustments (e.g., the Eureka Mignon or the Niche Zero), it's even just one or two detents or marks.
The rule of thumb: adjust the grind in small increments and make a shot after each change. Don't jump from "far too coarse" directly to "extremely fine" – you'll almost always overshoot the mark, and especially if you grind significantly finer, the grinder can even clog. A good rhythm: one small adjustment, one shot, taste, correct. After three to four shots, you'll generally be in the right range.
Important: After adjusting, discard the first small amount of ground coffee (2–6g is usually sufficient). There's still some coffee from the previous grind setting in the burrs. If this gets into your portafilter, it will distort the result. We call this coffee residue retention, and its amount varies from grinder to grinder.
When you need to readjust the grind
The grind setting is not a set-it-and-forget-it affair. Several factors change how coffee behaves at the same grind setting:
New coffee: Every coffee has a different density, cell structure, and roast. When you open a new bag—even of the same coffee—the grind setting might be slightly off. With a completely different coffee (e.g., from light to dark roast), you often have to adjust several steps.
Age of coffee: Freshly roasted coffee degasses CO₂. In the first few days after roasting, it resists water more strongly, and the extraction runs slower. At the same time, it bubbles and is not yet delicious. We recommend starting to brew espresso good two weeks after roasting. The longer the coffee has been open, the finer you will need to grind it over time.
Humidity: In high humidity, coffee grounds swell slightly and create more resistance. On muggy summer days, your espresso might suddenly run slower even though you haven't changed anything. Grinding one step coarser usually solves this.
If the espresso tastes sour — despite a fine grind
A common problem: the espresso tastes sour, so you grind finer. And finer. And eventually, the shot takes 40 seconds and still tastes sour. What's going on?
Mostly channeling. If the grind is very fine, but the coffee bed hasn't been distributed evenly, the pressure builds up unevenly. The water finds a channel through the puck and extracts everything there (bitter), while the rest of the coffee bed gets little water (sour). The result is an espresso that tastes simultaneously sour and bitter, no matter how fine you grind.
The solution then lies not in the grind setting, but in the preparation of the puck. Distribute the coffee evenly in the portafilter (WDT with a needle works well), then tamp evenly. More on this in our preparation guide. Pre-infusion can also help with channeling, as it saturates the puck more evenly before full pressure is applied.
If all this doesn't help and the espresso still tastes sour despite the correct time and ratio, the brewing temperature might play a role. Too low a temperature extracts fewer acid-binding substances. Two to three degrees more can make all the difference. But first, try grind size and puck preparation—that solves 90% of the problems.
Espresso Grind vs. Filter Coffee Grind
Espresso requires the finest grind of all brewing methods. For comparison: filter coffee is ground to about the consistency of fine sand, French Press like coarse sea salt. Espresso is somewhere between powdered sugar and fine sand—significantly finer than anything else.
There's a simple reason for this: the contact time for espresso is only 25–30 seconds. To extract enough flavor from the coffee in this short time, the surface area of the coffee particles must be as large as possible. Finer grind = more surface area = more extraction per second.
Therefore, for espresso, you need a grinder that can grind finely enough and provide a consistent particle size. Not every coffee grinder can do this. A usable espresso grinder costs approximately 200 Euros and up. Cheaper grinders may grind finely but inconsistently—with many coarse and many overly fine particles simultaneously. This leads to under- and over-extraction in the same shot. Our comprehensive espresso grinder test shows which grinders can achieve this. A curated selection of recommended grinders can be found in the Espresso Grinder Selection. Manual grinders are often the best choice in the affordable range under 100 Euros.
Adjusting the Grind: Achieving Results in Five Shots
If you have a new grinder or want to try a new coffee, this method will quickly get you to your goal. Define your recipe or use ours. We provide a recipe for every espresso in our shop.
Shot 1: Start with a setting that seems roughly right to you. Dose 18g, extract to 36g, and time it. If the shot takes under 20 seconds: grind significantly finer. Over 35 seconds: grind significantly coarser.
Shot 2–3: Correct in the right direction, each time in small steps. You should now be in the 22–32 second range.
Shot 4–5: Fine-tuning. Small corrections, taste, evaluate. If the espresso is within the time window and tastes good to you: done. If it's within the time window but doesn't taste good: read on at Espresso too sour or adjust the brew ratio (a little more or less water).
Yes, this will cost you five shots of coffee. Consider it an investment—afterward, you'll know where your grinder stands, and you'll only need to make minimal adjustments.
More on brew time and why it's your most important diagnostic tool: Espresso Extraction Time: When does the brew time really start?
Is your espresso tasting sour? Then check out our detailed troubleshooting article: Espresso too sour – what to do?
