is there any expiry date for lye crystals

[Kalpanaganesan]

hai
I have bought lye crystals some 2 years ago and I am storing it in air tight container.I have not used most of the crystals.can I use the same or is there any expiry date for the NAOH crystals

 

[earlene]

From what I have read from other soapmakers here at SMF, many have used NaOH that is older than that. However, first check that there are no clumps. Clumps of lye crystals in the bottle of lye means that it has absorbed moisture (from the air while the lid was off and also the air in the jar after the lid is closed). Clumpy lye would have a lower purity and mean that it would alter the superfat in soap you make. Meaning more superfat. You can test for lye purity or if you aren't there yet in terms of learning how to do that, you could try a test batch or two and alter your settings for superfat in your lye calculator. If it's clumpy, though and only a small jar, I'd buy new NaOH at my earliest convenience.