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

The dialling-in mindset: systematic versus intuitive approaches

There are two broad approaches to dialling in espresso, and they reflect different underlying philosophies about craft knowledge. The systematic approach — associated with Scott Rao, Matt Perger, and the SCA's training framework — begins with a baseline recipe, measures each variable precisely, changes only one variable per iteration, and uses refractometer TDS readings to verify that each change had the predicted effect. This approach treats dialling in as a controlled experiment whose results can be logged, reviewed, and reproduced. The intuitive approach — more common among experienced baristas with thousands of hours behind the machine — relies on visual, auditory and taste cues to make rapid adjustments without systematic logging. Both can produce excellent espresso; the systematic approach is more teachable and the intuitive approach is faster in production environments.

The challenge with dialling in is that variables interact rather than operating independently. Changing grind from one step to the next on a burr grinder changes not just particle size but also dose (the same volume of beans weighs slightly different amounts at different grind sizes, because finer grinding produces less aeration). Changing temperature changes both extraction kinetics and the perceived acidity of the espresso, because the body's perception of acidity changes with drink temperature as well as with actual acid concentration. An experienced barista doing intuitive dialling-in compensates for these interactions automatically; a beginner using systematic dialling-in needs to be taught that the variables are coupled, not independent.

Going deeper

Dialling in across a new bag of coffee is a microcosm of the broader skill of adaptation that defines professional barista competency. When a new bag from the same roaster arrives (same origin, same processing, same roast profile) but from a different harvest lot, subtle differences in density, moisture content and bean size may require grind adjustment even before the first shot. When a completely new coffee arrives — a seasonal release, a competition lot, a new origin — the dial-in process often takes 10–20 shots spread across two or three sessions before the recipe stabilises. Professional café operations budget for this 'dial-in waste' as a cost of serving quality, typically running 3–5 test shots per grinder before opening. Home users who accept that dialling in takes time and material learn faster than those who expect to get it right in one or two attempts.