Espresso machine

Forces hot water through a compacted bed of ground coffee at pressure, and holds enough thermal reserve to keep doing it while also steaming milk.

A pump raises water pressure; the group head holds the puck against that pressure while a boiler or heat exchanger supplies water at brew temperature. Everything that distinguishes one machine from another comes down to two questions: how stable is the brew temperature under repeated shots, and can it brew and steam at full demand without either one starving the other. Steam is the harder problem — turning water to steam consumes far more energy than heating it, so steam demand is what actually sizes the boiler.

• Start from PEAK cups per hour, not daily total and never floor area. A bar whose covers are spread evenly across the day needs less machine than a quieter one that takes most of its trade in a ninety-minute morning spike. Count the worst hour you expect and size for that; the rest of the day looks after itself.
• Group count follows the peak, and the planning thresholds below are a starting point to check against your own counts — not a rule. Two groups is the common answer for a single-barista bar with a helper. A third group only earns its space if you genuinely have two people on bar simultaneously, because a group nobody is standing at produces nothing and still costs energy and cleaning time.
• Size the boiler on STEAM, not brew. A menu that is mostly milk drinks loads the steam side far harder than the brew side, and steam recovery — how fast pressure returns after a jug — is what a queue actually feels. Ask about recovery under continuous steaming, not peak pressure on an idle machine.
• Choose boiler architecture from the coffee programme, not the budget. Single origin, light roast, or any intention to change brew temperature per coffee means dual boiler. A fixed dark-roast espresso and a milk-heavy menu is well served by a heat exchanger, and the money saved is better spent on the grinder.
• Spend on the grinder before the third group. A superb machine cannot fix an inconsistent grind, and an ordinary machine with an excellent grinder makes better coffee than the reverse. If the budget forces a choice, this is the one that is not close.
• Volumetric where the team turns over or skill is mixed; manual where a small, trained team owns the bar. Be honest about which you are — most operators overestimate how stable their team is.
• Confirm the electrical supply BEFORE selecting, not after. A three-group machine may require a supply the site does not have, and discovering that after delivery is an expensive week. This is a question for a licensed electrician and the local authority, and it is the single most common cause of a delayed opening.