How do I scale a recipe up or down?
What scales linearly and what does not — the things that catch people out when doubling a recipe.
- Difficulty
- beginner
- Time
- 10 min
- Read
- 2 min
Short answer
Ingredients scale; times, pan sizes and seasonings do not. Double the ingredients, keep the temperature the same, and expect the timing and the seasoning to need judgement rather than multiplication.
Doubling a recipe by doubling every number produces predictable failures: over-salted, over-spiced, and either raw in the middle or dried out. Knowing which things scale and which do not avoids all of them.
Step by step
- Scale the main ingredients directly.Flour, sugar, meat, vegetables, liquid. These do multiply, and weighing rather than using volume measures makes it accurate.
- Scale salt and spices cautiously.Start at around 1.5 times for a doubled recipe, then taste and adjust. Seasoning perception does not scale linearly and doubling frequently overshoots.
- Do not scale cooking time.Double the quantity does not mean double the time. A larger volume takes somewhat longer to heat through, but a doubled cake in the same tin size takes nearly the same time.
- Think about the pan, not just the amount.This is what actually changes the timing. Two cake tins bake in the same time as one; one deeper tin takes considerably longer and may not cook through.
- Keep the temperature the same.Do not raise the oven to compensate for volume. It burns the outside before the middle is done. If anything, go slightly lower and longer for a much larger quantity.
- Watch the pan size on the hob.Double the volume in the same pan means less surface area per unit, so it reduces more slowly, browns less and can steam instead of frying. Use a bigger pan or cook in batches.
- Be careful with raising agents.Baking powder and bicarbonate do scale, but errors compound. Measure accurately, and note that a very large cake may need slightly less proportionally.
- Halve carefully where an egg is involved.Beat the egg and use half by weight, or find a recipe designed for the smaller quantity. Half an egg is the classic scaling problem.
Tips
- Weigh everything when scaling. Volume measurement errors multiply, and cup measures are unreliable at the best of times.
- For baking, scaling beyond doubling is unreliable. Make two batches rather than one enormous one.
- Write the scaled quantities down before you start. Doing the arithmetic mid-recipe is where mistakes happen.
Questions people ask
Do I double the cooking time if I double a recipe?
No. Time depends on the depth and the pan, not the total quantity. Two tins take the same time as one; one deeper tin takes considerably longer.
Should I double the salt and spices?
Start at about 1.5 times and taste. Seasoning does not scale linearly and doubling usually overshoots.