pH
pH is a scale from 0 to 14 that measures acidity, where lower numbers are more acidic and higher ones are more alkaline, and it affects color, texture, and flavor.
Why it works
A pH of 7 is neutral, below 7 is acidic like lemon juice (about 2), and above 7 is alkaline like baking soda (about 9). Acidity tightens proteins, changes pigment colors, and slows some bacteria. Alkaline conditions soften vegetables and speed browning. This is why red cabbage turns pink in vinegar and blue-green with baking soda.
How to do it
- Use acid like lemon or vinegar to brighten flavor and keep fruit from browning.
- Use a pinch of baking soda to speed browning, as in caramelizing onions.
- Keep cabbage red with a splash of vinegar when cooking.
- Add acid after green vegetables are cooked to keep their color.
- Use pickling brines with enough acid to keep food safe.
Common mistakes
- Adding acid early to green vegetables, which turns them olive-brown.
- Adding too much baking soda, which makes food soapy and mushy.
- Ignoring acid in canning and pickling, where safety depends on it.
Questions
What foods are acidic?
Lemon, vinegar, tomatoes, wine, yogurt, and most fruits are acidic. Their pH is below 7.
Why does baking soda make onions brown faster?
It raises the pH, which speeds up browning reactions. It also softens the onions.
Why does red cabbage change color?
It contains natural pigments that turn pink in acid and blue or green in alkaline conditions.