Blog by Jonathan Eisen, Prof. at UC Davis. More info at: Lab Page , Profile , or Twitter. Go to fancy "dynamic" views here .
My mom has sent instructions for using red cabbage to do pH testing at home:Boil red cabbage in a small amount of water. Cool, and use the liquid to test household items like vinegar, lemon juice, baking soda, etc.(Its even better if you extract in alcohol but not as safe.)