Summary of "Основные ошибки бариста в работе с кофемашиной"

Common espresso / barista mistakes and how to avoid them

Speaker: Nikolai Strelnikov

If the grinder has been idle for 20–30+ minutes, purge a small amount first — leftover stale or “too young” grounds from earlier pulls will alter taste.
Don’t eyeball doses. Use a scale for accurate portafilter dosing; tamp depth alone is unreliable because it depends on grind size.
In very busy workflows where weighing every shot is impractical, tune the grind/dose so your recipe consistently hits target extraction times/weights.

Distribute coffee evenly with minimal pushes — each extra push changes tablet density.
Tamp consistently: same force, same angle, same technique each time. Recommended range: ~9–15 kg.
Inconsistent tamping causes unstable extraction and makes problems hard to diagnose. Avoid variable tamping pressure or angle (e.g., one press in the morning, different later).

Insert and lock the portafilter carefully and firmly to avoid breaking or cracking the puck (which causes channeling).
Start extraction immediately after locking in (immediate pour-over). Leaving the portafilter in the hot, humid grouphead before starting extraction changes the puck and harms extraction.

A fixed time (for example “25 seconds”) is not universal — it depends on coffee, machine, grind, and dose.
Prioritize weight/yield (grams out) and taste over a fixed time.

Example recipe: 18 g in → ~36 g out (1:2). Time might be ~24–25 s, but weight and taste are primary.

Keep a reserve of cups (about an hour’s worth) so you don’t leave the bar to fetch dishes.
Store cups bottom-up so you can grab by the handle and avoid touching the guest-facing rim.
Don’t stack cups too many levels high — top cups won’t warm properly and will result in cooler drinks.
Follow rotation: hot/used dishes to the back, fresh/clean items in front, to avoid unwarmed cups by mistake.
Be mindful that the machine can make rims very hot — a warm rim can burn guests.

Don’t add fresh cold milk into a pitcher that still contains leftover steamed milk — the old milk is already heated/degraded and will ruin texture and taste.
Avoid leaving large volumes of leftover hot milk. Use appropriately sized pitchers (small pitcher for a small cappuccino, larger for doubles or bigger drinks).
Leftover steamed milk loses sweetness and texture after about 65–70 °C and is not suitable for drinks; consider giving it to the kitchen for cooking instead of pouring down the sink.
If you frequently have large leftovers, reduce poured volume or change pitcher size to better match drink sizes.

Speaker: Nikolai Strelnikov
Equipment/terms referenced: direct-grind coffee grinder, portafilter/group head (Caldera/MPa group mentioned), tamper, scales, pitchers, coffee machine, cups.