Calcium lactate is a white tasteless powder used in cheese making, bread making and the modernist technique, spherification.
Unlike calcium chloride, which can sometimes result in a slightly bitter taste, calcium lactate can be used to make a calcium bath into which a flavoured sodium alginate solution is dropped. The reaction that takes place creates beautiful, flavoured caviar-esque spheres.
In cheese making calcium lactate is used to help the development of bacteria, improving the taste and texture of the cheese. Also use calcium lactate in bread making and beer brewing to help the yeast to develop.
The quantity of calcium lactate needed will vary, generally 1-9%, according to the recipe, the type of result desired and the acidity of the liquid it is added to.