Is my KOH 90%?

[Carl]

The KOH that I've been using does not state on the package if it is 90% or not.

How can I be sure? Or is it just generally understood that everything on the market is 90%?

I have not been checking the 90% checkbox on the soap calculator. Wondering if I need more lye?

 

[Obsidian]

Contact your supplier, they should have the info. Is your liquid soap cloudy or have a layer of fat floating?

 

[Carl]

Contact your supplier, they should have the info. Is your liquid soap cloudy or have a layer of fat floating?

No, it seemed fine other than the thickness which I spoke of in another post.

 

[DeeAnna]

The thickness issue has nothing to do with the KOH purity; it has everything to do with how much dilution water you used and the fats you used to make the soap.

KOH purity will affect the amount of superfat. If you assume the KOH is more pure than it really is, the soap will have too much superfat -- it will be cloudy and there could even be a layer of white fatty acids floating on the top. (Liquid soap can be cloudy for other reasons, but too much superfat is one of the first possibilities to think about.) If you assume the KOH is less pure than it really is, the soap will be zappy after the cook is complete. If your soap is reasonably clear and is not zappy, the actual KOH purity is probably close to what you assumed.

 

[emi]

I was going to ask about this today too as I've started making IrishLass's creamy liquid soap recipe. My KOH says 84%-92%. The recipe doesn't specify but I'm assuming 90%. Do you think my KOH will do ok for any 90% KOH recipe?

 

[DeeAnna]

Never assume someone else's recipe is correct as written, even if they say they're using KOH at 90% purity or whatever. People make mistakes or just plain don't know what they're doing even though they might sound like they do. It's so very easy to use Soapcalc or Soapee to ensure the amount of alkali is correct; there's no reason for not doing this.

 

[penelopejane]

I was going to ask about this today too as I've started making IrishLass's creamy liquid soap recipe. My KOH says 84%-92%. The recipe doesn't specify but I'm assuming 90%. Do you think my KOH will do ok for any 90% KOH recipe?

I think the average of your KOH is around 90% so I’d put that in the soap calc as 90% pure.

 

[emi]

Ok I'll do that. Thank you both for your advise!

 

[emi]

Never assume someone else's recipe is correct as written, even if they say they're using KOH at 90% purity or whatever. People make mistakes or just plain don't know what they're doing even though they might sound like they do. It's so very easy to use Soapcalc or Soapee to ensure the amount of alkali is correct; there's no reason for not doing this.

Oh no gosh your right. I mean that I should've run the numbers through a calc with my own KOH and not assume anything. In this case though I'm quite certain she (IrishLass who is the recipe maker) knows exactly what she's doing and I'm the one who doesn't! I just ran it all through the calculator with 90% KOH and I'm off. I used Soapmaking Friend Calc if it matters. Here's the recipe I was following posted by IrishLass.

Recipe to make 1lb. of paste, super-fatted @ 3% on Summerbee Meadow's Advanced Lye Calculator, with a 3:1 water to lye ratio (aka 25% lye concentration):
35% coconut oil (76 degree-type)........... 5.6oz/159g
30% castor oil...................................... 4.8oz/136g
20% cocoa butter................................. 3.2oz/91g
10% olive oil........................................ 1.6oz/45g
5% shea butter.................................... .8oz/22.6g
KOH................................................... 3.47oz/98g
Glycerin............................................... 10.4oz/295g

full recipe: https://www.soapmakingforum.com/threads/my-creamy-cocoa-shea-gls-tutorial.57974/

If I'm correct, for her KOH to be at 98g at 3%SF she was using a 95-96% pure KOH. If I calculate my KOH at 90% I'm 5 grams short needing 103g. I've already made my paste and it's at 8% SF only 98g of my 90% KOH, instead of 3% like the recipe says it should be at. The recipe adds meadowfoam oil and steric acid w/poly80 after dilution for additional SF so I think that's why she has a lower 3% SF in the initial paste-making recipe. So since I screwed up and my paste is now at 8%, does this mean I'm going to have a hell of a time diluting?! I've been through dilution failures before with LS which is kind of why I've stayed away from making it for a while, but wanted to give it another shot. Ugh. Any advise? Is it too late to heat the paste back up and add the 5 grams of KOH? And do you agree with penelopejane that I should calculate my KOH that says 84%-92% as 90% and not 88.5%?

 

[DeeAnna]

My KOH is about 95% purity as well per my supplier, so I calculate my recipes on that basis. This is a minimum by the way -- the purity is probably a bit higher as it comes from the manufacturer. Sticking with 95% works well -- the soap is clear if I use a recipe that should make clear soap and the soap isn't ever zappy unless I make a mistake. Those two findings tell me the soap is about right -- not overly superfatted and not lye heavy. Good enough.

You happen to know the minimum and maximum % for your KOH as it comes from the manufacturer, but you don't know exactly what you've got without testing. So you have to make an educated guess. I think the advice to use the 90% purity setting is a good choice as long as you're using an online calc like Soapcalc that gives only that option. If you use Soapee or other calc that's more flexible, you can sure use the average of 88.5% as your purity.

Whatever you choose, stick with it for a few batches. As you get more experience making soap, you'll learn if that purity setting works well for your particular KOH and the superfat settings you use -- you'll base that judgement on how your soap turns out.

Is your soap often cloudy when you use a recipe that should be clear? This unexpected cloudiness may be telling you that the real purity of your KOH is a little lower. You can compensate by reducing the superfat % by a percent or two (if using soapcalc) or reduce the purity setting by the same % (if using soapee) so there is less fat in your recipe. See how that works.

Is it often zappy even though you're doing an accurate job of making the soap? This might be telling you the real purity of the KOH is higher than the purity you've used in the calc. Compensate by increasing the superfat a tish so there's a tad more fat to react with the KOH (or increasing the purity if possible).

 

[emi]

Ok thank you so much for this info! This is only my 3rd or 4th attempt at making LS and all the previous times turned out clear. Out of those few, I don't remember any zappiness and I always calculated at 90% because soapcalc had no other option where in soapmaking friend calc you can change it to the tenth of a %.

But can you advise me on whether or not I can add KOH after the paste has been made, but before dilution? If I can I figure I should heat it up and add the 5g of KOH dissolved in a bit of water? Because right now I have an 8% SF and am afraid of proceeding to dilution then adding meadow foam oil because it will take the SF too high. Wouldn't 11-12% SF on LS be too high for LS? Or is it not necessarily?

 

[penelopejane]

Bumping this up so hopefully Susie or Irish Lass can answer your question for you. They are our resident LS gurus although a lot of people make it as well and might be able to help as well.

I am pretty sure that unless you keep LS SF below 3% it will be cloudy but I don't know if you can reheat it.

 

[DeeAnna]

From a theoretical point of view, yes, it can be done, but from a practical standpoint, I don't think I would because the paste is so thick. It's going to be tough to mix the KOH thoroughly into such a thick and sticky material.

When I do things like this, I prefer to add extra KOH to diluted soap. That does the job in a much easier and safer way, so I'm questioning why you're focusing on adding KOH to the paste.

But if you think this is what you need to do and you think you can get the KOH mixed well enough into the paste, try it. Just be really really careful and wear your usual protective gear -- eye protection is an absolute must because splashes are much more likely.

Don't get hung up on whether you can define the purity to 1/10 of a percent. Defining purity to the nearest whole percent is plenty good enough for soap making calculations.

Tip: It's a good idea to start a new thread when asking a very different question like this, so you have a better chance of getting good answers. I just about didn't read this thread, and if I hadn't, I would have missed your question.

 

[emi]

Thank you for replying! I was just about to try heating the paste back up to add the KOH. Ok, I will add the KOH after dilution like you said. I was going to dilute the paste in small amounts in mason jars so 5g KOH (the total amount needed for the whole batch) divided into small batches would've been a yet another step and harder to get accurate. So instead I'll just dilute the whole thing in my crockpot and then add the KOH, then move on to the final steps of SF.

And yes, I'll make sure to start a new thread when asking new questions.