How do you set espresso grind size on a coffee machine?

Espresso grind size is judged by flow rate and taste, not by eye. The grounds sit finer than fine salt, so a coffee machine setting off by roughly 0.1 can swing the shot: too fine slows the water and over-extracts into bitterness, too coarse speeds the flow and leaves the flavor weak and thin.

Pour-over and cold brew allow sieve checks for coffee particles, but pressurized short extraction magnifies every flaw, so dial in by watching the flow and tasting, then adjust dose, yield and extraction time to the bean. Front Street Classic Espresso Blend is suggested as a starting point for cafe-style shots at home.

Making a qualified espresso, grind size is often the most critical and headache-inducing part. Unlike pour-over and cold brew, espresso uses pressurized short-time extraction, and the state of the coffee bed gets magnified exponentially—slightly finer and it easily over-extracts into bitterness, slightly coarser and the flow speeds up, leaving the flavor weak and thin. This article starts with how to judge grind size, introduces how to quickly lock in the right setting range using flow rate and flavor, and adjusts the coffee-to-water ratio and extraction time based on bean characteristics. It also recommends Front Street Classic Espresso Blend to help you recreate café-level espresso flavor at home.

Super-automatic coffee machine grind settings - espresso grind size chart

When brewing coffee, the importance of grind size goes without saying. Once the setting is wrong, or the ground particles are uneven in size, coffee easily swings to one of two extremes: under-extraction or over-extraction. Compared with methods like pour-over and cold brew, espresso requires much finer grounds and demands more precise adjustment—only then can you nail the flavor of espresso.

Just how fine is espresso grind?

When talking about pour-over coarseness, Front Street likes to use the Chinese No. 20 standard sieve to see how many coffee particles pass through a fixed aperture, thereby calibrating the grind. But espresso follows a pressurized short-time extraction path, where everything gets magnified—the strengths magnified, and the flaws magnified just the same—so the demands on grinding are especially strict. Its grounds are finer than fine salt, and the naked eye simply cannot discern coarseness or uniformity; measuring with a sieve is also impractical.

If the grind is slightly too fine, water passes through the coffee bed more slowly, easily causing over-extraction; if slightly too coarse, water passes through the bed too easily, leading to under-extraction. And the deviation causing this might be just a 0.1-setting difference. So during brewing, we usually observe the flow rate and taste of the espresso to work backward and judge whether the coarseness is appropriate.

Choosing the right coffee beans

Actually, for making espresso, besides nailing all the parameters, Front Street believes choosing the right beans is equally key—after all, the beans are the foundation of whether a cup tastes good. To make café-style espresso at home, we recommend trying Front Street Classic Espresso Blend. This coffee is blended from three origins—Brazil, Indonesia, and Vietnam—combining the caramel sweetness of American coffees with the wild character of Asian coffees. To maximize the coffee's rich aroma and to give the extracted espresso abundant, dense crema, Front Street Coffee uses a deep roast. Whether made into an Americano diluted with water or a latte paired with milk, it works well. You can order it from the Front Street Taobao store or the Front Street Tmall flagship store.

How do you first narrow down the appropriate grind size range?

When you get a bag of unfamiliar coffee beans and want to brew a good cup, the first step is determining the grind size. If the grinder hasn't been used yet and you're unsure which setting range to start with, you can first try grinding a small amount of beans at different settings. When the coffee grounds feel like flour—soft to the touch with no grittiness—it's about right.

Next, you can apply the common espresso formula to extract. Front Street suggests using a 1:2 brew ratio, meaning 1 gram of coffee grounds extracts about 2 grams of coffee liquid, with the time controlled between 20 and 30 seconds. For example, Front Street uses a 20-gram capacity portafilter basket, so it doses 20 grams of coffee grounds and extracts 40 grams of coffee liquid. If the time is less than 20 seconds, the flow rate is too fast; if the espresso flow exceeds 30 seconds, the flow rate is too slow.

A fast flow rate means water passes through the coffee grounds in too short a time, and the coffee often tastes weak or sour—so you need to grind finer. Adjusting the setting relies on experience accumulated day to day: if the gap from the target time is less than 5 seconds, you can move 0.2 increments each time; if the gap is larger, be bolder and adjust by 0.5–1 increment. Even if it goes from too long to too short all at once, you can use that to lock in the range of grind settings, then gradually narrow it down. Conversely, too slow a flow rate means the grind is too fine, water struggles to pass through the coffee bed, and the coffee easily turns bitter—so you need to grind coarser.

How do you find the correct grind setting?

The formula Front Street mentioned above only helps us quickly find a suitable grind range; it doesn't mean the espresso extracted this way will necessarily taste good. Ultimately, you still need to consider the characteristics and taste of the coffee beans themselves to judge whether the extraction is qualified.

If the espresso tastes distinctly burnt and bitter but the strength is moderate, it may be that too long a time caused excessive release of bitter compounds, so you can grind slightly coarser. If the crema on top of the coffee liquid is pale in color and thin in texture, it may be that the tail-end extraction is excessive; you can reduce the weight of the coffee liquid—that is, extract a little less—and it's suggested to raise the brew ratio to between 1:1.5 and 1:1.7. When the espresso has fairly rich flavor but a short finish, you can extract a bit more coffee liquid, trying a ratio of 1:2.5.

Finally, the extraction formula is only a reference. If you're boxed in by it, it actually becomes hard to adjust toward good flavor, and you end up endlessly tweaking the grind, wasting coffee beans for nothing. The 1:2 ratio isn't necessarily the golden ratio for a given bean—sometimes 1:1.7 tastes better, sometimes 1:2.5 shines. The time doesn't have to be pinned at 25–30 seconds either; sometimes 36 seconds or 24 seconds is the state in which this bean tastes good. Front Street is daily café production, and parameter adjustments are built on accumulated daily experience. If we're brewing at home at lower volume and it's harder to judge, Front Street suggests keeping good records and summarizing the relationship between extraction parameters and flavor performance—this makes it easier to adjust quickly and reduces unnecessary waste.

The above content is compiled by CoffeeHunters, a coffee news website.