Safe pH range (acid vs base) for food One of my molecular cookbooks goes into the use of acidity / alkalinity in cooking. What it doesn't describe is what safe pH values are that you can still serve food at.

Note: I am not looking for danger or 'cooking at the edge'. I'm a chemical engineer by training and won't be likely to mess this up, and yes, I'd have access to litmus paper or similar tools.

If the 'safe' range is broader than a (commonly) accepted range where food still tastes good, that'd obviously be good to know as well.
According to this neat chart on Wikipedia: http://en.wikipedia.org/wiki/File:PH_Scale.svg

Lemon juice is around 2, and baking soda around 9. Our digestive juices are around a 1, so it's probably safe to go a bit less than 2, but you wouldn't enjoy it. Baking soda is 9, and milk of magnesia is 10...both of which are safe to consume in small quantities, but I wouldn't want to serve a dish in that range.

So...I'd probably stick with 2-9 as an acceptable safe range. As far as taste goes, we're not really wired to enjoy the taste of alkaline. Between 2 and 7 (acid to neutral) is the tasty range.