E. E. Kellogg, Science in the Kitchen
“ Utensils.—For bread-making purposes, earthen or china ware is preferable to either tin or wooden utensils: being a poor conductor, it protects the sponge from the cold air much more effectually than tin, and is much more easily kept clean and sweet than wood. The utensil should be kept exclusively for the purpose of bread-making, and should never be allowed to contain any sour substance. The bowl should be thoroughly scalded before and after each using. Use silver or granite-ware spoons for stirring the bread. Iron and tin discolor the sponge. ”
