Osmosis
Osmosis is the movement of water across a thin barrier, like a cell wall, toward the side with more salt or sugar, and it explains brining, curing, and wilting.
Why it works
Water moves through cell walls toward the side with more dissolved salt or sugar until things even out. That is why salted eggplant weeps liquid and a salted cucumber turns limp. In meat, salt pulls out some water, then dissolves and gets drawn back in with the seasoning, which is the idea behind brining and dry brining.
How to do it
- Salt vegetables like cucumber or eggplant and let them sit to draw out water.
- Pat them dry to remove the extra liquid before cooking.
- Salt meat ahead of time to season it through and through.
- Dress salads right before serving to keep leaves crisp.
- Use sugar or salt on fruit to make juices for a quick sauce.
Common mistakes
- Salting salad greens too early, which makes them wilt.
- Salting vegetables right before sauteing when you want browning.
- Forgetting to drain salted vegetables, which turns the dish watery.
Questions
Why does salt draw water out of food?
Salt makes the outside more concentrated, so water leaves the food to even things out. That process is osmosis.
Why do my vegetables get watery when I salt them?
Salt pulls water out of their cells. Salt later in cooking or pat them dry when you want browning.
How does osmosis help pickling?
Salt and vinegar move into the vegetable while water moves out, which seasons it and makes it firm and tangy.