lye percentage off

[wingster]

I measured out my lye incorrectly, what will happen to my soap or will it be ok?
recipe (5% super-fat)
26.5 oz Rice bran oil
2.65 oz castor oil
5.3 oz almond oil
7.95 oz palm oil
10.6 oz coconut oil
20 oz water
7.15 oz lye
I measured 7.5 oz of lye
how bad will it be :???:
thanks for any help!!

 

[sistrum]

Run your recipe back thru a soap calc changing your lye amount to what you used and see what superfat if any it gives you.

 

[wingster]

This is the recipe, but i do not see where i can change the lye amount to what i used
http://www.soapcalc.net/calc/ViewRecipe.asp

 

[sistrum]

Oops, sorry I don't use use soap calc and didn't know you couldn't do that. Just start changing your super fat level down until you reach the amount of lye you used. See if that works. If not when I get back home ill run it thru soap maker for you.

 

[Hazel]

7.5 oz lye is 0% superfat.

How I did it is I just entered your recipe into SC and started at 0% to see what lye amount it showed. It showed 7.53 oz so didn't have to keep trying different percentages.

 

[engblom]

7.5 oz lye is 0% superfat.

How I did it is I just entered your recipe into SC and started at 0% to see what lye amount it showed. It showed 7.53 oz so didn't have to keep trying different percentages.

While I do not recommend 0% superfat because of variation in oil and because of measuring errors, it is still most of the time not dangerous as the lye probably has been absorbing some moisture from the air.

This has been visible in each batch of liquid soap. When it comes to liquid soap you have 0% superfat and then you add even 10% more lye just to be sure you have no excess oil. (You adjust the ph in the final product.) For liquid soap I'm not selling I'm not caring if it has a thin layer on top of fat. I omit the 10% extra lye and so far I have never had to adjust the ph. 0% superfat according to the calculator has always had some excess fat because of moisture in lye.

 

[DeeAnna]

I don't believe it's moisture in the air, unless I'm really missing the point of Engblom's explanation. Carbon dioxide in the air reduces the pH by reacting with excess NaOH to make sodium carbonate. For bar soap, this happens only on the outside surfaces, so don't rush to use the soap -- give it a plenty long cure.

Also, sodium hydroxide used by soapers is less than 100% pure. The online soap calculators are based on 100% NaOH, so if you use SoapCalc, etc., there is a "hidden" bit of superfat in every soap recipe. Probably something around 2% to 4%.

 

[engblom]

I talked about moisture in the "dry" lye. I even had lye that had been forming big pieces because of moisture. When you measure the dry lye you do not count with the hidden moisture in it.

Simply what I mean is that 7.5 oz of lye is not really 7.5 oz of lye as the moisture bound in it is also having some weight.

 

[DeeAnna]

Yup, I didn't catch your full meaning, Engblom. Thanks for clarifying...

 

[Hazel]

Simply what I mean is that 7.5 oz of lye is not really 7.5 oz of lye as the moisture bound in it is also having some weight.

I'd still recommend rebatching since this is on the edge. I don't know how accurate wingster's scales are and what is 7.5 oz actually might be 7.6+. It's not hard to rebatch and add a little extra oil.

For a 5% superfat, wingster can just add 3 more ounces of rice bran and wouldn't have to let the soap cure for an extended time.

 

[shunt2011]

I agree with Hazel. I wouldn't risk it either. I measure everything in grams and don't even bother with ounces anymore. I think it's more accurate with less margin of error if the scale is calibrated appropriately. I wouldn't use a 0 superfat soap except for laundry soap.