### Help Support SoapMakingForum:

#### wbocrafter

##### Well-Known Member
I tried using the soapcalc to determine how much lye I need but I don't understand the chart. I put water in my molds to see how much lye solution I would need and I get 1032 grams. Then I entered lard: 50%, coconut oil: 20%, olive oil: 20% and pig lard: 50%. I want a soap that is creamy & feels good to the skin and also a lot of lather. Can someone tell me how much lye I would need or how I would calculate it? Or is my recipe out in left field? As you can tell I'm a newbie. I've used recipes from soap books in the past with success but this is the first I have tried to make my own recipe.

#### Kamahido

Correct me if I am wrong but your recipe appears to add up to 140% and lists lard twice. 1032 grams of sodium hydroxide would require a LOT of oils. Quite the batch size for someone just starting out.

#### wbocrafter

##### Well-Known Member
Thank you for picking that up. I erroneously entered lard 2 times. I came up with the 1032 grams of water by filling the molds I want to use with water & then pouring the water into a measuring cup. I got about 5 c. Water. I thought I needed to convert it to grams so that everything was in grams. Does this make any sense? I forgot to enter that I was using 7% castor oil & 23% coconut oil, not as I originally posted.

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#### doriettefarm

I'm working on a batch right now that might be a good example to use. I just got a new 2lb mold so that typically means it will hold around 2lbs of soap batter (https://nurturesoap.com/collections/loaf-soap-molds/products/2-pound-basic-mold?variant=20034854086). Since you're combining oil + lye water you only need about 1.5lbs of oil to fill that size mold. You can also see in my recipe below the total batch weight is 1028 grams so that's really close to what you need.

The amount of lye required will vary depending on what combination of oils/butters you choose . . . that's why double-checking recipes with a lye calculator is so important. I like soapee.com and soapcalc.net for formulating recipes but there are plenty of others available. I would select the default superfat of 5% and a lye concentration of 30% like my example below.

The soap calculator will usually complain if your oil percentages don't total up to 100%. You can select different combinations of oils to see how the recipe properties and fatty acid profiles change.

#### Kamahido

I understand that you want to figure out how much your mold hold but I also want to point out that your mold filled with water vs your mold filled with soap will be very different weights. Think of the analogy of 50 lbs of feathers vs 50 lbs of bricks. The volume of these two things would be drastically different. Hopefully someone can elaborate on how sizing works as that is beyond me.

I just ran your recipe through my soap calculator and it appears that it should be everything you specified you wanted. Good job there. To figure out how much water and sodium hydroxide you need, you must learn how to use a soap calculator. This is vital for safety! Try soapcalc.net or google "Soap Calculator".

thanks so much.

#### gdawgs

##### Well-Known Member
Check out this thread on how to figure out how much oil to use to fill a mold.

Basically you measure your mold dimensions in inches (Length, width, height), multiply those three numbers together, which gives you the volume in cubic inches. Then take that number and multiply it by .4. That's how much oil you need in ounces. It works really well.

So in your case, you have a volume of 1032 cubic centimeters(since you used water and grams). Converting that to cubic inches gives you just under 63 cubic inches. So 63 X .4 = 25.2 ounces of oil.

Now if you use Soapcalc, step two asks you what the weight of your oils is. Put 25 in there, fill out the rest, and your mold will be filled nicely.

#### wbocrafter

##### Well-Known Member
thanks for that info. I just asked on a thread how you knew what to put in for weight of oils. this was very helpful. My 2nd question was how to know what % of lye to use & how do I know this?

#### Susie

Supporting Member
Here is a tutorial on how to use Soapcalc.net. Basically, you put in how much (ounces, grams, or percentages) of each oil you want, and the total amount of oil you want to use (ounces or grams), and set the lye concentration, and hit calculate. The calculator will tell you how much water and how much lye to use.

#### gdawgs

##### Well-Known Member
Doing a quick back calculation, if you want to use your water method of calculating oil to use using grams, you can do what you did (fill mold full of water, then weigh water). Then multiply by .69.

But .7 is easier to remember and is close enough.

So 1032 X .7 = 722 grams of oil

#### Steve85569

Supporting Member
How I know how much lye to put in is what I am using the lye calculator ( such as soapcalc.net) for. The program calculates the amount of lye needed to saponify each oil completely - less the amount of superfat I have deducted. The default on soapcalc is 5% which works as a good starting point.

One of the other things that a lye calculator does is show the approximate properties of the recipe. This helps me to not make a soap that will require an extremely long cure period just to be "ick why did I do this".

#### gdawgs

##### Well-Known Member
Is the thread for mold volume calculations. Ounces use the same formula as gdawgs BUT with a correction of 0.40. Both formulae consider that you will be using "full water".
I may have added confusion there with the second post.

.4 is for converting cubic inches of mold volume to ounces of oil needed.

.7 is for converting cubic centimeters of mold volume to grams of oil needed.

#### Chefmom

##### Well-Known Member
To answer the lye/water question. After you plug in the size batch you need at soapcalc and the % of oils and fats etc. Click "calculate recipe" for the recipe to formulate, THEN click on the "View or Print Recipe" just below it and the recipe in print format with the lye and water amounts in ounces and grams will open up in a NEW TAB. Then you can type in any notes at the bottom, give it a title and print it out.