How to Scale a Recipe for Batch Cooking

What Scales Cleanly, and What Does Not

Proteins, vegetables, grains, tinned goods and most liquid scale straight up. Double them and the dish is the same dish. Salt scales too, but taste at the end rather than trusting the arithmetic, because a larger volume needs proportionally slightly less to taste the same.

The things to hold back are the assertive ones: chilli, strong spices, garlic, and anything smoked or fermented. Start at roughly three quarters of the scaled amount and add at the end if it needs it. You can always add heat; removing it means cooking more of everything else.

Fresh herbs and acid - lemon, vinegar, yoghurt - go in at the end regardless of scale, because both fade with cooking time, and a doubled batch cooks for longer.

The Pan Is the Real Constraint

This is the mistake that spoils more scaled-up batches than any seasoning error. Browning needs the surface of the food to reach a temperature where water has boiled off. Double the mince in the same pan and the water cannot escape fast enough, so the food sits in its own liquid and steams grey rather than browning.

The fix is space, not heat. Brown in two or three batches and combine, or move to a genuinely larger pan. Turning the heat up on a crowded pan burns the bottom while the middle still steams.

The same logic applies to a roasting tray. Vegetables on a crowded tray go soft rather than caramelising, so a doubled tray bake wants two trays, and ideally two shelves with a swap halfway.

Time Does Not Double, but It Does Change

A doubled stew does not need twice as long, but it does need longer than the original - mostly because a larger volume takes longer to come up to temperature, not because it cooks more slowly once there. Judge by the food rather than the clock, and start checking around the original time.

Reduction is the exception that catches people out. A sauce thickens by evaporating from its surface, and doubling the volume in the same pan barely changes the surface area, so a doubled sauce can take far longer than twice as long to reduce. Either accept a looser sauce, use a wider pan, or reduce a portion of the liquid separately.

Baking is the one to be careful with. Cakes and anything set by eggs do not scale reliably, because depth changes how heat reaches the centre. Two tins of the original size beat one large one.

Scale for the Portions You Actually Want

Recipes are written for four because that is a household, not because four is a useful number for prep. Work backwards from what you need: five lunches, or three dinners plus two frozen. Then scale to that rather than to a tidy multiple, and weigh the protein into portions before cooking so the finished batch divides evenly.

It is also worth scaling less than you think at first. A tripled recipe you have never made before is three times the risk, and a batch nobody enjoys is worse than a small one that ran out.