Batch brewer

Brews filter coffee in volume automatically — meters hot water across a flat bed of grounds and delivers the finished coffee into a server for holding.

Water is heated in a tank to a set point and then metered, as a measured volume, through a spray head above a basket of grounds. Everything the machine controls happens in that sentence: the temperature the tank holds, the volume it delivers, and how evenly the spray head spreads it. The extraction itself happens in the basket exactly as it would in a hand brew — saturation, contact, drawdown — which is why the brewer cannot rescue a bad grind and why an uneven spray pattern reads as channelling. What separates one machine from another is recovery: brewing draws the tank down and the element has to bring it back before the next batch, so the second and third batches of a rush are where a machine either holds temperature or quietly stops brewing to spec. After the cycle, everything is about holding — coffee sitting on applied heat keeps cooking, which is the entire argument for a thermal server over a hot plate.

• BREW THE BATCH YOU CAN SELL INSIDE THE HOLD WINDOW, NOT THE BATCH THE MACHINE CAN MAKE. This is the whole discipline of batch brew and almost every venue gets it wrong in the same direction. A server holds coffee for a stated window and then it is discarded; a batch bigger than the window's sales is waste that has already been paid for, ground, brewed and labelled. Size the brewer so that its SMALLEST sensible batch matches your slowest hour, not so its largest matches your busiest.
• SHAPE OF DEMAND BEATS TOTAL DEMAND. A venue selling filter steadily through the day wants small frequent batches and therefore fast recovery. A venue selling it in a morning wave wants tank capacity. Both might sell the same daily total, and they need different machines. Count the shape before the volume.
• ASK ABOUT RECOVERY BETWEEN BACK-TO-BACK BATCHES, not about tank size. Tank size is a number a brochure is happy to give you; the useful question is what the temperature does on the second and third consecutive batch, because that is the batch a queue is waiting for.
• THERMAL SERVERS ONLY. Do not specify a hot-plate brewer for a venue that cares about the coffee, and do not accept one because it came bundled. If the budget is tight, buy fewer servers rather than heated ones — a server is a consumable-class item and the second one can arrive later; a hot plate is a permanent decision to degrade the product.
• PLUMB IT IF FILTER IS PERMANENT, AND TEST THE WATER FIRST. Plumbing removes the human variable and makes the batch repeatable by anyone on the team, but it also connects an untreated supply directly to a heated tank if nobody checked. Treatment is specified after the local supply is tested, never from the manual.
• COUNT THE SERVERS, NOT JUST THE BREWER. A one-server operation cannot brew while it is serving, so the machine's cycle time becomes a service gap. Two servers per head is the point at which batch brewing actually behaves like a continuous offer.
• PUT IT WHERE SOMEONE OTHER THAN THE BARISTA CAN POUR IT. Batch coffee's operational value is that it is the one hot drink that does not need the espresso station. If it is sited inside the barista's working envelope, that value is thrown away and you have bought an expensive way to add steps to the busiest person in the building.
• DO NOT BUY A BATCH BREWER TO FIX A GRINDER PROBLEM. It brews what it is given. If the filter grinder is wrong, or is the espresso grinder in disguise, the brewer will reproduce that fault with great consistency.