What does dialing in mean in espresso?

Dialing in refers to the iterative adjustment process of all espresso preparation parameters — primarily grind size, dose, water-to-coffee ratio and extraction time — to achieve the optimal sensory profile of a given coffee on a given machine and grinder. It is a daily practice in specialty coffee bars, because every new coffee, every climatic change and every new batch of beans may require readjustment.

Dialing in is to espresso what tuning an instrument is to music: an indispensable prerequisite to performance. Its importance stems from the fact that espresso extraction is a highly sensitive process: minute variations in grind size (a few microns), dose (0.1g) or extraction time (1 second) produce radically different sensory results. The goal of dialing in is to find the combination of parameters that gives an espresso whose extraction yield is in the ideal 18-22% window, with a TDS (Total Dissolved Solids) of 8-12%.

The standard dialing-in procedure follows a logic of systematic variable reduction. Start by setting a base ratio (e.g. 18g coffee for 36g liquid, 1:2 ratio — the most common for a balanced espresso), then adjust grind to hit a target extraction time (typically 25-30 seconds for a classic espresso, sometimes 28-35 seconds for a lungo). If the espresso runs too fast (under-extraction, sour and hollow taste), tighten the grind. If it runs too slowly (over-extraction, bitter and astringent), open it slightly.

A crucial and often underestimated aspect: beans change behaviour with roast age. A coffee roasted 3 days ago will still be degassing heavily and be harder to extract (more open grind needed). The same coffee at 14 days post-roast will be more stable. At 30 days, it will be flatter and may require a finer grind. Professional baristas document their settings daily — a dialing-in log is as important a quality management tool as a stock register.

Beyond mechanical parameters, dialing in also involves a sensory component: the barista tastes each shot to evaluate the sweet-bitter-acid balance, texture and length. This taste feedback is as important as physical measurements (weight, time) for refining the profile. Competition baristas push this process very far, recording dozens of variables per extraction to find the perfect combination for their performance.

Espresso dialing-in parameters