Most ingredients multiply freely; these few need a cook's judgment.
Most ingredients can be multiplied or divided freely, but a short list needs judgment. Multiply them blindly and a bigger batch turns out too salty, too spicy, gummy or oddly boozy. Knowing which ingredients don’t behave — and which way they lean — is what separates a scaled recipe that works from one that’s merely correct on paper.
Scale salt, pepper, chili and strong spices conservatively and correct by taste. Scaling up, hold back to about 1.5× for a doubled batch and adjust at the end. Scaling down, a small batch can taste flat, so keep it close to the original and taste. The rule in both directions: season under, taste, bring it up.
Baking soda and baking powder scale with the batter, but they’re concentrated enough that precision matters more than proportion. Too much leaves a bitter, soapy taste and a cake that domes and sinks. Level every spoon.
You can’t pour a fraction of an egg, and in baking they do structural work. Beat a whole egg and measure by tablespoon — about 3 per large egg.
Wine, spirits, vanilla and almond extract punch above their volume; scale them gently and give alcohol time to cook off. Thickeners like flour and cornstarch depend on how fast liquid evaporates, so add gradually and judge by consistency rather than committing the full scaled amount.
The Recipe Scaler flags these non-linear ingredients automatically so you know exactly where to use a little judgment.