Does sodium hydroxide go bad?
I can remember years ago calculating the concentration of a sodium hydroxide solution by measuring its specific gravity with a hydrometer. If you to adjusted your recipes to use a lye solution instead of dry lye, you could do the same. Hydrometers are simple (essentially a float with a scale) and easy to use. They’re widely used in various endeavors like brewing beer, making maple syrup, preparing ceramic glazes, testing car batteries, etc. Homebrewing shops, auto and lab supply places carry hydrometers. Unfortunately a quck Googling on “lye hydrometer soap recipe” turned up a bunch of Anarchist Cookbook references.
