Acidic foods and drinks can cause decay. Below are the 'pH values' of some foods and beverages. The lower the pH number, the more acid product. Anything with a pH lower than 5.5 can cause tooth decay. "Alkaline" have a high pH number and the neutralizing effects of sugars. PH 7 is the middle number between acids and bases.

- mineral water (still) pH 7.6
- milk pH 6.9
- cheddar cheese pH 5.9
- lager pH 4.4
- orange juice pH 3.8
- grapefruit pH 3.3
- pickles pH 3.2
- cola pH 2.5
- red wine pH 2.5