Here's everything worth knowing about whey and how to pick it, what it is, how to store it, and what to use instead, plus 7 recipes to cook tonight.

What is whey?

Whey is the thin, watery liquid left behind when milk curdles and the solid curds are strained off. Make cheese or yogurt at home and you are left with a pale, slightly cloudy liquid in the pot: that is whey.

It carries the milk's lactose and minerals plus a little protein, with a clean, faintly tangy, milky taste.

Two kinds turn up in kitchens. Sweet whey drains from rennet-set cheeses like cheddar, while acid whey comes from acid-set dairy such as yogurt or ricotta; the acid version tastes noticeably more sour.

Whey is also dried into the protein powder sold for shakes, but that is a concentrated product. This page is about the fresh liquid you can cook with.

How to Use Whey

Whey earns its place as a stand-in for water or milk in baking, where it adds a faint tang and feeds a more tender crumb. Swap it measure for measure for the water in a bread recipe and the loaf browns a little deeper and keeps longer.

Several yeast breads here lean on it for exactly that. An Italian Herb Bread and an Orange Spice Bread both use whey as the dough liquid, and a Dough Magic relies on it to build a soft, supple texture.

It also works as a cooking liquid beyond bread. Simmer grains or potatoes in whey instead of water for a subtle savory depth, or use it as the acidic dairy in a batter, the way a Sour Milk Devil's Food Cake calls for soured milk.

Acid whey in particular makes a good brine. Its mild acidity tenderizes chicken or pork much like buttermilk, and it carries salt and seasoning into the meat overnight.

Pairing and Common Mistakes

In baking, whey suits honey, whole grains, and warm spices, the same partners that flatter a tangy buttermilk dough. Its acidity also reacts with baking soda, so it can replace buttermilk in pancakes and quick breads.

The most common mistake is pouring whey down the drain. A batch of homemade ricotta leaves several cups of perfectly usable liquid that most cooks throw away out of habit.

The second mistake is boiling it hard to reduce it. The leftover proteins in whey scorch and stick at a rolling boil; keep it at a gentle simmer when you cook with it.

A note for gardeners and septic systems: acid whey is acidic and high in lactose, so dumping large amounts on the garden or into a septic tank can cause problems. Cook with it or compost small amounts instead.

Substitutes

In baking, buttermilk is the closest swap for acid whey, matching its tang and its reaction with baking soda, used cup for cup. Thin plain yogurt or kefir with a little water for a similar result.

For sweet whey, plain milk or water stands in directly; you lose a little tang but the structure holds. If a recipe wants whey purely for moisture, water with a squeeze of lemon or a spoon of vinegar approximates the gentle acidity.

Buying and Storing Whey

Liquid whey is rarely sold in stores, so most cooks get it as a byproduct of making cheese or straining yogurt. If you do see whey for sale, it is usually the dried powder for baking and shakes, not the fresh liquid.

Fresh whey is perishable like the milk it came from. Strain it through a fine cloth to catch stray curds, refrigerate it in a sealed jar, and use it within about 5 to 7 days.

It freezes well for up to 3 months, so freeze it in measured amounts for baking.

Trust your nose. Fresh whey smells clean and milky, with at most a gentle yogurt tang. A sour or off smell means it has spoiled and should go.

Quick facts

In Chinese

乳清

British (UK) term

Whey

en français

petit lait

en español

suero

Recipes using whey

There are 7 recipes that contain this ingredient.

All 7 recipes