Butter

Unsalted is the default

Baking and most cooking use unsalted butter, so you control the salt yourself — salted butter varies by brand. If salted is all you have, cut the recipe's salt (roughly 1–1.5g of salt per 100g of butter).

Why it burns

Butter smokes at about 150°C. What burns is not the fat but the milk solids — the protein and lactose. So there are two fixes.

• Mix it with oil — a little neutral oil pushes the browning point later.
• Clarified butter (ghee) — milk solids removed, smoke point up around 250°C. It is why Indian cooking uses ghee for dishes like Butter Chicken.

Browning those solids on purpose gives you beurre noisette — nutty and excellent, but take it off the heat the moment the specks colour and the aroma rises.

Cold, melted, or at room temperature

The temperature is part of the technique.

• Cold — makes layers. The flakes in a Croissant come from cold butter folded into dough; once it melts into the dough, the layers are gone.
• Room temperature (creaming) — holds air. Cookie and cake batters.
• Cold cubes at the end — emulsifies a sauce to a gloss (monter au beurre). Added all at once, or into something too hot, it splits — see Why sauces split.

Storing

One to two months sealed in the fridge, six months frozen. Butter absorbs odours strongly, so wrap it in foil or keep it in a closed container. A butter dish left out should hold only a few days' worth.

Substitutes

• Neutral oil — 100g butter ≈ 80ml oil. You lose the flavour and the layering.
• Olive oil — fine for sautéing, changes the flavour in baking.
• Margarine — usable in baking, but a different water content changes the texture.