% I purity of KOH

[Milk Machine]

I purchased some potassium hydroxide from Bulk Apothecary to make liquid soap. The recipe I am using states the formula was made with 90% pure KOH. There isn't any indication on Bulk Apothecary's website or on the containers what percent pure their product is. I have an email in to their documents department but does anybody know off hand? Their website just calls it "high grade". Thanks

 

[Zany_in_CO]

If you've never made LS before, there are good tutorials for learning the basics on Alaiyna B's Blogspot. Check out her Shampoo tutorial for pictures.

To avoid problems, use the Recipe Feedback Forum to get input for each batch you try before you try it. You have lots to learn and that's a good place to pick up TIPS.

There are about as many ways to make LS as there are LS'ers! That being said, you can start with the basics and tweak from there.

I wouldn't worry too much about the KOH purity unless and until you have a problem with the end result. Make a small 16 oz. /500 gram trial batch. Here's how to set up your formula.

 

[earlene]

Here is DeeAnna's video for determining lye purity:



Generally many lye calculators default to 90% pure for KOH, although some let you set the purity yourself. I see that some vendors make claims of 95% purity and others claim as high as 99% purity for commercial grade KOH, but once they are open to the atmosphere (opening the lid and allowing air to come in contact with the contents) purity will degrade the longer exposed to the ambient moisture in the air, so either accept the calculator's default or learn to follow the testing procedure DeeAnna spells out in her video above.

But according to Wikipedia, most commercial KOH is around 90% pure. Potassium hydroxide - Wikipedia

See also: NaOH or KOH purity check | Soapy Stuff
and: https://classicbells.com/soap/NaOH_KOH_Purity_Check.pdf


FYI, I checked Bulk Apothecary's KOH SDS and it makes no reference to purity, either.
https://www.bulkapothecary.com/content/SDS/Sodium Hydroxide SDS - BA19.pdf