soaping without a soapcalc

[CaliChan]

I was wondering if any of you out there knew the calculations to figure out how much lye you need for the oils without something like soapcalc or any of those sites. I just want to know for oils that arent included in soapcalc like nut butters and such.

 

[bodhi]

weight of oil x sap value

 

[lsg]

You would have to know the saponification value of each fat, butter or oil. And you would have to know how much liquid to use with the lye.

http://www.millersoap.com/soapdesign.html

 

[sistrum]

I can't find my paper work on this, it's been a long time since I've done it by hand, but you should be able to find the instructions somewhere on line. Just remember if you go by Thefactories sap value it's written as the KOH value not NaOH so you will need to convert it. The water part is easy, just use twice as much water as lye. Sorry not much help but keep looking. I know the info is out there some where. Good luck. Sissy

 

[dragonblossom]

Isg, on that link it does say sap values for sodium hydroxide. So if I was using sodium hydroxide for making CP soap, those numbers would be accurate, correct? I've been wondering how one finds sap values. Many have mentioned it but I haven't had time yet to do a search I'm probably going to use a soap calc, myself, but it's good to know there's a reference out there for the sap values if I need them!


Sent from my iPad using Soap Making

 

[lsg]

dragonblossom, I always use SoapCalc. I think it is one of the best lye calculators available. As far as the saponification values being correct on the site I referenced, you can always double check by googling "saponification values of oil."

 

[DeeAnna]

A few sources for saponification (sap) values, other oil properties, etc:

http://www.thesoapdish.com/
http://summerbeemeadow.com/content/properties-soapmaking-oils
http://www.certified-lye.com/lye-soap.html#LyeSoap
http://www.millersoap.com/soapdesign.html
http://www.soapcalc.net/info/SoapQualities.asp
https://www.thesage.com/
http://www.colebrothers.com/soap/oils.html
https://www.soaperschoice.com/

Letcavage, Elizabeth (ed) and Buck, Patsy. Basic Soap Making: All the skills and tools you need to get started. 2009. Stackpole Books, Mechanicsburg, PA.

Watson, Anne L. Smart Soapmaking. 2007 Shepard Publications, Olympia, WA.

Edit: Oh, and don't forget -- Dunn, Kevin. Scientific Soapmaking.

Be vewy, vewy careful, because the most common way to present saponification values is for KOH. If the source doesn't specifically say the numbers are for NaOH, they very likely are for KOH.

Sap values can vary quite a bit for a particular fat, so you need to decide which sap value you want to use. For example, coconut oil has an NaOH sap value ranging from 0.178 (Soap Dish) to 0.181 (Soapers Choice/Columbus Foods) to 0.183 (SoapCalc) to 0.184 (Majestic Mountain Sage) to 0.192 (Certified Lye).

If you find sap values that are less than 1, the units are grams of lye (KOH or NaOH) / gram of fat. If you find sap values that are greater than 1, the units are milligrams of lye / gram of fat. Divide the "big" sap value by 1000 to get the most commonly used "little" sap value. Edit: The "little" sap value can be stated as either gram of lye / gram of fat OR ounce of lye / ounce of fat.

To convert a KOH sap value to an NaOH sap value, divide the KOH value by 1.403. This number is the ratio of the molecular weights of KOH and NaOH. In chemistry-speak, 1.403 moles of KOH weigh the same as 1 mole of NaOH.

Good luck!

 

[DeeAnna]

Nut butters are not 100% fat, so I would calculate the amount of fat in the nut butter and use just the fat in my saponification calculations. The balance would be just solids that add bulk to the soap or would be water-based liquid that I would put into the water-phase part of my soap recipe.

To use the peanut butter in my pantry as an example, only 16 grams are actually fat in each a 32 gram serving. If I put a total of 32 grams of this peanut butter in my soap, I'd put the 16 grams of peanut oil into the fat portion of the recipe, and the other 16 grams in the "other ingredients" part of the recipe. Peanut oil is in most soap calculators, but I doubt you'll find a sap value for peanut butter.