The shelf life of lye, sodium hydroxide, when properly stored is one year. After a year it is possible for your lye to work, but you should do a small batch to test whether the lye is still good. If it is actually expired, then it may not come to trace quickly or could separate after it is poured or set up.

Does lye water expire?

To ensure the lye works properly, we recommend using it within one year of purchasing. It needs to be sealed tightly and stored in a dry place. Lye is hygroscopic, meaning it attracts moisture. If it’s exposed to moisture in the air it won’t be as effective in your recipe, and the soap may not saponify fully.

Does lye water need to be refrigerated?

Adding lye to water causes a exothermic reaction that causes the lye water to reach temperatures up to 200 ° F. Because the lye solution becomes so hot, it needs time to cool for soaping. … If the lye solution is too cold, it can solidify the oils and butters upon contact.