pH — the measure of hydrogen ion concentration in a solution, on a scale of 0 (most acidic) to 14 (most alkaline), with 7 neutral — affects colour, texture, flavour perception, microbial safety, and Maillard browning in ways that the cook who understands pH can control deliberately.
**Colour and pH:** - Anthocyanins (red cabbage, blueberries, red onion): red in acid (pH < 7), purple at neutral, blue-green in alkaline. Adding vinegar to braised red cabbage preserves the red colour. - Chlorophyll: bright green in neutral/mildly acidic conditions; olive-green (pheophytin) in strongly acidic conditions. Add an acid source to green vegetable cooking water and the colour turns olive within minutes. **Texture and pH:** - Proteins denature at different rates depending on pH — acidic marinades tenderise meat by beginning protein denaturation. - Pectin (the cell wall cement of fruit and vegetable) dissolves more rapidly in alkaline conditions — alkaline cooking softens vegetables faster. **Microbial safety and pH:** - Pathogenic bacteria are most active in the pH range 4.6–9.0. Below pH 4.6 (moderate acidity), most pathogens cannot grow — the basis of pickling and acidified food preservation. **Alkaline browning:** - As discussed in MC-27 — higher pH accelerates Maillard browning. Baking soda (pH ~8.3 when dissolved) applied to surfaces produces faster browning at lower temperatures.
Modernist Cuisine