Espresso Shot Extraction Calculator

The Italian SCA standard for a normale double shot is 1:2 by weight: 18 g of ground coffee in, 36 g of liquid espresso out, pulled in 25 to 30 seconds. This is the default starting point for almost every modern third-wave espresso menu and the recipe most home machines and prosumer grinders are calibrated against. If you only remember one ratio, remember 1:2 in 27 seconds.

A ristretto is a concentrated shot pulled at a 1:1 to 1:1.5 ratio, typically 18 g in to 18 to 27 g out. Less water passes through the puck so the cup tastes denser, sweeter, and more syrupy, with less of the harsher late-extraction compounds. Many Italian espresso bars pull ristretto by default. The downside is a higher caffeine concentration per ounce and a smaller cup volume, which is why it does not work well in milk drinks larger than a cortado.

A lungo is a diluted shot pulled at a 1:3 ratio or longer, typically 18 g in to 54 g or more out. The extended contact time pulls more soluble solids and tastes more like a strong drip coffee than a classic espresso. Pull a lungo when you want a longer drink without adding water afterward (which would be an americano), when the bean is roasted on the lighter side and benefits from a longer extraction, or as a base for a long milk drink like a flat white pulled in the Australian style.

The Specialty Coffee Association's gold cup standard for espresso is 18 to 22% extraction yield, computed as (yield grams * TDS%) / dose grams using a refractometer reading. Below 18% the shot tastes sour, grassy, and salty (under-extracted). Above 22% the shot tastes bitter, ashy, and astringent (over-extracted). The 18 to 22% window is the band where the sugars, acids, and bitter compounds balance into a sweet, full-bodied cup. Most well-dialed shots land between 19 and 21%.

Grind size is the primary control. A shot that pulls in under 20 seconds is running too fast, which means the puck is too porous and water is channeling through it; grind finer. A shot that takes over 35 seconds (a choked shot) means the puck is too dense for water to push through; grind coarser. Adjust the grinder one or two notches at a time, dose the same amount, tamp with consistent pressure, and time again. Dose, tamp pressure, and basket size matter too, but for a given recipe grind size is the single biggest lever.