Twenty members of the Cook's Illustrated staff tasted 10 supermarket balsamic vinegars three ways: plain, in a vinaigrette with olive oil and mustard, and cooked into a glaze on asparagus topped with Parmesan cheese and olive oil. They measured pH in the test kitchen; higher numbers indicate lower acidity. An independent laboratory  analyzed the vinegars' sugar content (in grams per 100 ml) and viscosity (in centipose, or cP, a unit measure of viscosity in which water is "1" and olive oil "100"). The complete list of balsamic vinegars tested may be found at Cook's Illustrated.