# Lye Calculator

### Help Support SoapMakingForum:

#### Abrachibi

##### Member
I know soap can be made without lye calculator. I do that myself. disolve my caustic soda in water of any amount then look for the spicific gravity of lye then measure my oils and lye at the ratio of 2:1. But someone told me he uses 4kilograms of caustic soda, dissolve in 4 litters of water and combine the lye solution with 4 liters of oil without cheking the specific gravity of the lye water. I do'nt know the outcome of such a soap. Does anyone has another method of soaping without using lye calculator.

#### atiz

##### Well-Known Member
But why would you? Lye calc makes things so easy...
I'm not sure I fully understand your method, but don't see why it works. How much oil you need also depends on what kind of oils you have, etc.

#### shunt2011

Staff member
I'm not understanding your process/method at all. Why would you want to make soap without a soap calculator. It's simple and accurate. Your way sounds like it has a lot of unknown factors and could lead to a disaster and not so good soap.

#### DeeAnna

##### Well-Known Member
Is there a reason why you want to use this kind of method? Is your alkali not very pure? Or are you using a random mixture of fat? Or are you using wood-ash lye? Or are you using a boiled method of making soap?

I agree with the others -- if you have reasonably pure alkali and know the specific types of fats going into the soap, why not use a recipe calculator? You can do the math by hand or use an online calculator as is best for your situation. There's no reason not to.

edit: The approximations you and the other man are using are not really wise for making soap with a hot process or cold process method. If using a boiled method, an approximation will work okay because the boiled method allows you to correct for excess lye or excess fat at the end of the boiling process.

"...disolve my caustic soda in water of any amount then look for the spicific gravity of lye then measure my oils and lye at the ratio of 2:1. But someone told me he uses 4 kilograms of caustic soda, dissolve in 4 litters of water ..."

If the other person is using alkali of a known purity and always dissolving 4 kg of the alkali in 4 L of water, that gives a fixed alkali concentration. How is that materially different than your method in which you use a hydrometer to check the concentration?

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#### Abrachibi

##### Member
Okay, thank you all. You might just find yourself in asituation where you have no access to calculator that means you will never soap. A serious delima

#### Abrachibi

##### Member
Is there a reason why you want to use this kind of method? Is your alkali not very pure? Or are you using a random mixture of fat? Or are you using wood-ash lye? Or are you using a boiled method of making soap?

I agree with the others -- if you have reasonably pure alkali and know the specific types of fats going into the soap, why not use a recipe calculator? You can do the math by hand or use an online calculator as is best for your situation. There's no reason not to.

edit: The approximations you and the other man are using are not really wise for making soap with a hot process or cold process method. If using a boiled method, an approximation will work okay because the boiled method allows you to correct for excess lye or excess fat at the end of the boiling process.

"...disolve my caustic soda in water of any amount then look for the spicific gravity of lye then measure my oils and lye at the ratio of 2:1. But someone told me he uses 4 kilograms of caustic soda, dissolve in 4 litters of water ..."

If the other person is using alkali of a known purity and always dissolving 4 kg of the alkali in 4 L of water, that gives a fixed alkali concentration. How is that materially different than your method in which you use a hydrometer to check the concentration?
4 kg of caustic soda in 4 litters of water doesn't gives you a specific gravity of 1275. you must find your specific gravity and have it at 1250 or 1275. You can't just assume fixed alkali concentration of 4kg caustic and 4liters of water to have your standard S.G of 1250 or 1275. When I get my S.G I use my oils and lye at ratio of 2:1 and have a perfect soap that takes 4 weeks to get hard.

#### DeeAnna

##### Well-Known Member
Actually a solution made with 4 kg of commercial NaOH in 4 L (4 kg) water will have a specific gravity of 1.54. You do not have to measure specific gravity to make a consistent lye solution if you are using commercial NaOH of known purity. You can use specific gravity OR you can use a decent scale. Either way, you can get an accurate, repeatable result.

Even if you do choose to measure specific gravity as a check on the concentration, it does not have to be in the 1.250-1.275 range for making soap. I use NaOH solutions with specific gravities ranging from 1.28 to 1.54 and get good results from them all.

It is your choice to use lye solution in the 1.25 to 1.28 range, because you have learned this method makes good soap for you. I can see why you have no reason to change, and that is fine, but you may want to broaden your understanding of soap making.

Just because your method works for you, doesn't mean other people are wrong if they use another method. Your method is valid. And so is his. And so is mine.

Study the chemistry and math of saponification in more depth and learn other ways of thinking about how to make soap. You might still prefer your method, and again that is fine, but with more knowledge, you will understand your way is not the only way.

Okay, thank you all. You might just find yourself in asituation where you have no access to calculator that means you will never soap. A serious delima
As long as I have paper and pencil, I can calculate a soap recipe. Online soap recipe calculators have only been around for 20 years or so, but soap makers did just fine before that time without the internet, hand held calculators, or hydrometers.

Your assumption that I can't make soap without a calculator is no more valid than if I would assume you can't make soap if your hydrometer breaks. If you understand the chemistry and math of saponification, you have the tools that will let you use other alternatives if you can't use your usual method.

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#### earlene

##### Grandmother & Soaper
Okay, thank you all. You might just find yourself in asituation where you have no access to calculator that means you will never soap. A serious delima
Not all lye calculators are internet dependent. I have a stand alone one on my computer, and used to have one on my phone, neither of which require(d) internet access.

Okay if I am faced with no electricity I might be up a creek for a little bit, but as common as the written word is, there are also several printed books with instructions on how to calculate lye for making soap and some of us have those as well or can dig one up if need be. Or maybe we already have a tried and true recipe that we can fall back on and not have to worry about making new calculations.

#### Nona'sFarm

Supporting Member
I see you are from Cameroon. Is this the normal process for making soap there? Just curious. I've always used a soap calculator, but also could calculate it manually based on the SAP values of the oils.

#### Mobjack Bay

Supporting Member
Not all lye calculators are internet dependent. I have a stand alone one on my computer, and used to have one on my phone, neither of which require(d) internet access.

Okay if I am faced with no electricity I might be up a creek for a little bit, but as common as the written word is, there are also several printed books with instructions on how to calculate lye for making soap and some of us have those as well or can dig one up if need be. Or maybe we already have a tried and true recipe that we can fall back on and not have to worry about making new calculations.
Earlene, just print off a table of NaOH sap values for the fats you use (and keep it in a safe place until the power goes out), borrow a triple beam balance (unless you already have one), fire up the camp stove or grill to melt your hard fats, and you'll be good to go.

#### Abrachibi

##### Member
I see you are from Cameroon. Is this the normal process for making soap there? Just curious. I've always used a soap calculator, but also could calculate it manually based on the SAP values of the oils.
Most people including soap companies here do beautiful soaps without lye calculator