Calculate potassium hydroxide

[shaan]

I bought potassium hydroxide that mentions-

Minimum assay(acidimetric) - 85%
Maximum limits of impurities
Carbonate (K2CO3) - 2.0%
Chloride (CI) - 0.03%
Sulphate (SO4) - 0.02%

How should i calculate it in any recipe using this KOH?

 

[DeeAnna]

The number to focus on is the minimum assay of 85%. You can safely assume the purity of the KOH as received from the manufacturer is a percent or two above 85%. With time, the purity will gradually drop due to exposure to carbon dioxide (CO2) and water in the air.

The easiest way to deal with this uncertainty about purity is to just use the 85% minimum as the actual purity. The more complicated way is to make a guess about the purity and adjust the number downward as time goes on. I think Susie adjusts her purity, but I can't remember if she does this for NaOH only or also for KOH. I assume the purity is a constant value for either lye.

When you have decided what purity % to use, here's how to use it:

Use your favorite soap recipe calculator to calculate the ideal KOH needed for your recipe. In other words, you want the amount of KOH required at 100% purity. Tip: If you are using SoapCalc, do NOT tick the box for 90% KOH purity. I'm not sure if you have any control over how the SummerBeeMeadow calculator handles KOH purity. You will have to check that if you use this calc.

Calculate the actual KOH amount based on the actual purity:
Actual KOH = (Ideal KOH) * 100 / (Actual purity %)

Example:
SoapCalc says your recipe needs 125 g KOH at 100% purity.
You would weigh out this amount of actual KOH at 85% purity:
Actual KOH = 125 g * 100 / 85 = 147 g

 

[shaan]

Thanx DeeAnna! Can you please check my recipe.. i will be using the same lye for this recipe.. i am making this for use as a shampoo for oily hair.

Canola oil- 15% - 75g
Castor oil- 15% - 75g
Coconut oil- 15% - 75g
Rice bran oil- 10% - 50g
Olive oil- 35% - 175g
Sunflower oil- 10% - 50g

Water@ 38%- 190g
Lye - 121g ( acc to the formula you told, actual lye×100÷85. Actual was 103g.. so i did 103×100÷85=121g.)

Will this recipe yield a transparent soap? I want to make it thick and with a lot of cleaning bubbles.. if i add 1120g dilution water,will it be ok? And neutralization water around 141g.. and if i use whole part glycerin or half water,half glycerin, do i still need to neutralize it? And if i use around 35g borax and 70g glycerin after dilution, would it help create more bubbles in less quantity of soap?

 

[The Efficacious Gentleman]

Are you trying to make a liquid soap? If so, we can move it there where more LS experts can get to see it

 

[Susie]

I don't seem to have as much difficulty with KOH absorbing water as NaOH. But, I weigh my lye when I close it after using it, then weigh it before opening. If it gains weight, I calculate how much, and what percentage it is, then adjust my superfat appropriately.

And no, you can't set purity on SBM Advanced. I am horrible in math, so it is a good thing my KOH does not absorb water like my NaOH.

 

[DeeAnna]

Shaan -- I think this thread should be moved to the liquid soap forum. (Can you help, Gent?) I'm not the best at analyzing LS recipes because I'm rather a newbie at liquid soap. I bet Susie, Irish Lass, and others may surely help. Your math to adjust for purity looks correct.

Susie -- Superb tip! I hadn't though about weighing the lye container for weight gain during storage. That's a stellar idea that I will take to heart.

 

[The Efficacious Gentleman]

 

[Susie]

I life in a high humidity environment. I keep my NaOH bottles in the original (still sealed) bags until I need them, then in the bottle, in a Ziploc bag, with silica gel packets once opened, and I still get moisture in there. I write the weights right on the bag with dates so I know exactly what I am dealing with. I could not think of any other way to get the correct numbers.

I don't know what calculator you used. Transparency depends greatly on amount of superfat, FO/EO, and the types of oils. I don't know what superfat you used, but I see no likely suspects in the oils to cause cloudiness. You will want to figure 3% superfat or less, and be careful on the type/amount of FO used. If you are talking about having a colorless soap, it will most likely be light amber.

Neutralization is not necessary if you use 0-3% superfat rather than a negative superfat. Saves you having to do an extra step with the whole borax thing.

Use of glycerin has no impact on clarity, bubbles, or neutralization.

Borax has no impact on bubbles. Look to castor, coconut, and sugar for bubble increase.

Hand made liquid soap is very thin unless you use some other product to thicken it. Period.

I have a question for you- what are you trying to gain by having so many oils?

 

[Susie]

OK, I ran your recipe through Soapcalc.net. I got(with the formula DeeAnna shared) the 103.69 g KOH using 3% superfat. This means you do NOT need to neutralize. Skip the whole borax step. I do not use the Soapcalc.net for liquid soap because they never use enough water. I would use 311 g water with that recipe to mix the KOH in. If you want to use glycerin to speed trace, I would use half the water amount in glycerin. But you will want to mix the KOH with the 155 g water first, then once dissolved(and still VERY HOT), add the 156 g glycerin. Then add that to the oils. If you are going to CP that soap, add that hot mixture to the solid oil(coconut), stick blend til melted. Add that mixture to the liquid oils and stick blend to trace(paste). Then cover it and clean up. Check it for zap after you clean up(10-15 minutes), and it should be good to go. If it is still zappy, recover and give it half an hour before retesting.(I have never needed more time, but anything is possible.) Break up the paste into lumps as soon as possible with the spoon to give more surface area for dilution.

Dilution will depend on your oils. With that blend, I would start with half the paste weight(weigh your pot before adding anything, then weigh the pot with the soap in it, the difference is paste weight) in water, and add as needed til you are down to 1-2 small lumps.

Let us know how it goes, please?

 

[shaan]

Thanx all for your reply. I used the same recipe with 103 g of KOH(85% pure)..i added 200g water and 100g glycerin.. it took a long time to come to trace..then i cooked for around two hours till it turned vaseline like,amber colored..i diluted it with 75% water,but it formed a film on top after mixing, instead of diluting well..so i added more water,but then it got thin..i did not get the desired consistency because of added water, but it looks well till now..it was clear liquid till i added essential oils to it..i will use it tomorrow then let you how well it clears,and how does it feel..
Susie, there was no particular reason to add so many oils,but to save olive oil.

 

[Susie]

That's a valid reason.

I can't get my liquid soap thick either because I do not want to add anything else to it. There are others who can tell you what to use to thicken soap. But hand made liquid soap is extremely thin unless you add something to it.

 

[shaan]

Hey i tried it today..it was foaming well. Here is my before n after pics of using shampoo..i applied oil in my hair at night and washed off in the morning..i am happy with everything but thickness of the shampoo.

 

[shaan]

Sorry for two pics..one was with flash,second one widout flash.

 

[Susie]

If you are happy with how the shampoo works, that is the most important thing. Someone will step in with instructions on how to thicken before long. I tried to find you a thread that tells you definitively how to thicken it, but too many instructions that I know are not great ideas are out there, so it is a better idea to just wait for IrishLass, DeeAnna, FGOriold, or any of the other great folks that know how to thicken give you a safe, effective method.

 

[shaan]

And this is how the soap looks

 

[hud]

And this is how the soap looks

I would just use it and next time I'll reduce the water amount to keep it thicker ( I am chicken when it comes to soap):razz:
Great job though.

 

[shaan]

Hey susie! I was in a hurry to make soap,i just used 103 g of KOH.. but now i wonder how did we get it? I mean,i used the formula given by DeeAnna, and it came out to be around 121g.. then how did we get 103g,if we calculate manually? Is it like 3% of 500g= 15.. so 121g-15g= 103g of KOH? And water you suggested around 300g..is it because you prefer 1:3 of lye:water? Please correct me if i am wrong.

 

[DeeAnna]

"...i just used 103 g of KOH.. but now i wonder how did we get it? I mean,i used the formula given by DeeAnna, and it came out to be around 121g.. then how did we get 103g..."

The 103 g is the weight of 100% pure KOH. That is the number your soap calculator came up with.

If your KOH is only 85% pure, then that 103 g is not enough. You have to weigh out a little more to account for the impurities in your 85% pure KOH. The weight of 85% pure KOH you needed to weigh out was:

actual KOH = 103 * 100 / 85 = 121 g

 

[Susie]

I am horrible in math. You have my abject apologies. Next time listen to DeeAnna. Your soap may not be clear. Again, my apologies.

Yes, I like the water at 1:3 ratio.

Hud- your thought on less water for dilution...it truly does not work.

 

[DeeAnna]

Ah, Susie, I'm counting on you to show me how to do things right -- I figure it's a fair trade if I can help once in awhile with my calculator skills.

In fact it's a much better trade from my point of view! You were the one who got me to making LS, and I'm having a blast with it.