Different Lye Calculators

[John Harris]

Hi, All!
I am preparing to make a recipe from Susan Miller Cavitch's book, The Soapmaker's Companion. It's called Soap Essentials Bar 2. (I thought I would ease myself back into soapmaking.) I'll be making a triple batch - 45 bars. In the past, I always used MMS's lye calculator, but I was recently introduced to SoapCalc. I ran the recipe on both calculators and found that numbers were very close except for the water. MMS gave a range of 1212 to 1818 mls. SoapCalc gave a specific number at 1842 which is 24 mls higher than MMS's highest value. I don't want to "drown" the soap! But then, maybe one of you more experienced ones will tell me not to worry about it? In the past, I would have taken an amount somewhere in the center of MMS's range of values. In my notes, I had written 1616 mls as what I was planning to use.

Also, maybe someone can take this opportunity to educate about the effects of too much or too little water.

 

[amd]

I would use either one, but it's hard to judge without knowing where you set your lye concentration and what your batch size is (I know you say 45 bars, but is that 4 oz bars or 1/2 oz bars? you get the point.). It would be better to see both calculations though with the whole recipe.

too much water (25% lye concentration) and soap may take longer to unmold and bars may warp during cure. I have a high hard oil recipe and used 25% for years and only had problems when I used other recipes. On the plus side, more water encourages gel and glycerin rivers. Too little water and you run the risk of not fully dissolving your lye (you need at least 50% lye concentration to properly dissolve). Less water will also trace and unmold faster. The amount of water you use does not affect cure time.

 

[John Harris]

Is there a way to upload the SoapCalc image onto this thread?

 

[DeeAnna]

This question, in one form or another, comes up a lot, so I put a handy-dandy table on my website with my suggestions. https://classicbells.com/soap/waterRatioConc.asp

I'm guessing you are using Soapcalc's default of "38% water as % of oils" to determine the amount of water in your recipe. I recommend not using that -- I suggest using either water:lye ratio or lye concentration, whichever you prefer. There's a link at the end of my table that explains why I don't like "water as % of oils" to determine the water content.

 

[John Harris]

Here's the recipe that should make 45 4 oz. bars. All the calculations were done on SoapCalc.
For this recipe I used the water to lye ratio method for calculating lye and water amounts.

__Oil/Fat ____% ____Grams
1 Olive Oil ___36.83 ___1,785.90
2 Palm Oil ___24.56 ___1,190.70
3 Coconut Oil_ 28.09 ___1,362.00
4 Shea Butter __5.16 ___250.00
5 Beeswax ____4.12 ___ 200.00
6 Soybean Oil __1.24 ___ 60.00
Totals ___100.00 ___4,848.60

Other details:
Total oil weight 4848.6 g
Water as percent of oil weight 27.80 %
Super Fat/Discount 7 %
Lye Concentration 33.003 %
Water : Lye Ratio 2.0300:1
Sat : Unsat Ratio 47 : 53
Iodine 52
INS 157
Fragrance Ratio 31
Fragrance Weight 150.31 g

And still more details:
Water __ 1,347.87 g
Lye ____ 663.97 g
Oils __ 4,848.60 g
Fragrance _ 150.31 g

This is the first time I will be using the water to lye ratio method. I'm a little nervous. Before, I just plugged in my numbers at MMS and never had a problem (except for one batch that tried to seize on me).

So, does this look like it will work? Especially the lye and water amounts and ratios?

 

[DeeAnna]

Those numbers will give you 45 bars at about 5.5 ounces when cut. Reduce that by 8% for a 6-8 week cure, and the final weight is going to be just around 5 ounces per bar.

The 33% lye concentration is pretty standard for a lot of the soap makers here. Your recipe is pretty typical, so I'd think this 33% would work fine.

Do you know you like to use soap with a higher coconut oil content? Or is your skin normally dry? If you like a goodly amount of coconut oil in your soap, the recipe will be fine especially with the higher 7% superfat. If you have dry or sensitive skin, however, the 28% coconut might be too cleansing and drying.

My rule of thumb is to use a minimum of 5% for most typical soaping oils to see any real effect in the soap, so your 1% soy is a token amount in my opinion. If you feel the need to use soy, raise it to 5% and reduce the olive. Or eliminate the soy and increase the olive. (Castor is an exception to this 5% rule of thumb.)

Beeswax is not a typical soaping oil. I don't use it, but I believe the usual advice from those who do is to limit it to a max of 2%. Hopefully someone will chime in to verify that. The palm and shea are going to make a hard, long lasting bar, so I'm honestly not sure the beeswax is going to add all that much benefit. But there are people who swear by it, so your mileage may vary. If you still want to use it, just don't overdo.

 

[John Harris]

Thanks for the help, DeeAnna!

You wrote, "Those numbers will give you 45 bars at about 5.5 ounces when cut. Reduce that by 8% for a 6-8 week cure, and the final weight is going to be just around 5 ounces per bar."

Pardon my denseness, but reduce WHAT by 8%?

 

[DeeAnna]

As a bar of soap ages, it naturally dries and loses weight because water evaporates out of the bar.

My rough estimate is a given soap bar will lose about 8% of its freshly cut weight after 6-8 weeks. So if your soap starts at 150 grams / 5.3 ounces, the cured weight will be about .... 150 X (100 - 8) / 100 = 150 X 92 / 100 = 138 grams or 4.9 ounces.

If a person sells soap, the labels should not show the original cut weight for this reason.

I never label with the exact weight at 6-8 weeks either, because soap doesn't stop losing weight after 8 weeks -- the weight loss is quite a bit slower by that time, however. If I were selling that 4.9 ounce bar, the label would show a net weight of 4.5 ounces.

 

[penelopejane]

Honestly I wouldn’t make a huge batch for the first time trying a recipe. Can you find a small mold that would give you 4 soaps in a 1 pound batch?

Beeswax is a real pain to work with and in a huge batch like this it is going to be especially challenging. I’d start with 1% or 2%. More is not better.

Soapcalcs are all a bit different. Stick to soapcalc and just learn how to use it to tweak your recipe.

 

[John Harris]

Thanks for the input, penelope. I will give it some thought. My very first batch back in 1998 was 40 bars too because that was the size of the wooden mold that was made for me by a carpenter friend. I just jumped in with two feet like a totally naive noob. My recipes were always very simple: Olive, coco, palm, 1 or two luxury oils, maybe some botanicals. and then heavy on the essential oils. I think so many people wanted my soap was because of the smell. (Someone once asked me what cologne I was wearing. It was just residual patchouli from my shower that day.)
Then one day, my carpenter friend presented me with a 112 bar mold. With that development I was "off to the races" and made mountains of soap ... but, as I said, it was all pretty bland stuff. As I said in another thread, at one point I had 1200 bars drying or curing. People walking past my house would tell me they could smell my soap scents.
So! Keep bees'wax low. Master SoapCalc. And make a test batch of the recipe. I will definitely do the first two. As for the third one ... well ... we'll see! ;-)

 

[penelopejane]

An easy way to reduce the size of a mold is to make a vertical divider with some coreflute or timber and then put a piece of timber down one end to support the vertical divider. You can make whatever size you want depending on the length of the piece of timber.

It is a great way to perfect a recipe and make a variety of soaps with the same amount of ingredients.

 

[DeeAnna]

"...I will definitely do the first two. As for the third one ... well ... we'll see!..."

We're always full of advice -- perhaps too full at times. Stick around long enough and you'll join our pack. Anyways, take the advice that works for you and leave the rest.