Different soap/lye calculators

[Shazzer]

Hello!

I'm wondering a bit about how different calculators work. I basically always use Soap Calc, but I'm located in a different country and here nearly all soap makers use a different calculator. The characteristics it shows you are a little different so I wanted to try it out, as that one shows a Nummer about the longevity of a bar I wanted to see.

To my surprise, the categories which are the same gave wildly different results for the exact same recipe, AND it showed me a different measurement of water and lye to use?! Particularly the different measurements of lye and water surprised me - how can that be different, for the exact same inputs??

The amount of oils, the lye concentration, the superfat, and the percentage of each oil was the same in both.

 

[earlene]

Is this the one you are using? What's nice about it is that you have verious language choices. It is the only one I have run across that does. I only tried it a few times, so don't recall much about how it compares.

Mendrulandia


I have tried several calculators, butthis one, which has so many great feaures that it has become my favorite go-to calculator:

Soapmaking Recipe Builder & Calculator


Some of the features I like:

Results are calculated on-the-fly. I don't have to go to a second page once I have entered all my oils. I can change oils and all calculations are done while making those adjustments. (That second page calculation results thing with soapcalc has always annoyed me.)

I can save seemingly endless numbers of recipes. (If there is a limit, I haven't reached it yet.)

I can add photos of my soaps to the saved recipe.

Entering custom oils and custom additives is a feature I have found quite unique and I do use both to add items not built into the calculator.

Those are just a few of my reasons for preferring this calculator over many others I have tried.

I do use soapcalc for this special feature, though: Sort Oils
It has the best sortable list of oils that I have found so far, and is quite useful for when I want to look for which oils are higher or lower in a particular fatty acid.

Edited to add link to first calculator.

 

[Fenchurch]

To my surprise, the categories which are the same gave wildly different results for the exact same recipe, AND it showed me a different measurement of water and lye to use?! Particularly the different measurements of lye and water surprised me - how can that be different, for the exact same inputs??

Measurement of lye can vary because of the saponification index or the oils: different sources (references) will provide different values for a same given oil. One reason is that it really varies according to the variety of the plant that provides the oil, or the time it was harvested etc. and it's also an average. For instance for hazelnut oil I found saponification index from 191 to 195 depending on the calculator I checked my recipes with.

For water, I guess it's because there are several ways to calculate a water quantity suitable for a recipe AND because it's in fact a range within which the water quantity will be OK. Different calculators may not use the same value within the range - some even provide a usable range, not a single value.

Happy Bubbles,
Stéphanie

 

[Mobjack Bay]

It looks like the first calculator @earlene listed defaults to 99% NaOH purity, but allows the user to change the value. The second calculator assumes 100% purity. That variable will affect the calculation as will the superfat/excess fat used to calculate the recipe. If you calculate a recipe with the NaOH at 99% purity and set the superfat to 5% and then switch the NaOH purity to 100%, the calculated amount of NaOH needed for the recipe should go down.

I use the second calculator linked in Earlene’s post. Since I know that the NaOH I use is in the 96%-98% range, I set my superfat to 2%.

I like the calculator for the same reasons Earlene mentioned, but also occasionally experience some quirks when I use it. An example is changes in formatting of the printout if I switch from printing from the main recipe page versus printing from edit mode.

 

[Shazzer]

Thank you! The other calculator I used was this: Handmade by Kathrin - Handgesiedete Seifen

It is in German. But I will try that other one for sure. I was worries I might make some kind of error die to the different calculations, but it seems then that it is typical and should be fine!

 

[earlene]

Thank you! The other calculator I used was this: Handmade by Kathrin - Handgesiedete Seifen

It is in German. But I will try that other one for sure. I was worries I might make some kind of error die to the different calculations, but it seems then that it is typical and should be fine!

Thank you. I had not seen that one before. Is it only available in German? Google is having a hard time translating some of the words (using the web page translator). But from what it does translate, I can see it lists some of the oils a bit differently than I understand. I'd probably have a hard time with it. I wonder if the oils available to you are labeled so differently (the Coconut oils, specifically.) And it doesn't list many of the oils I do use. But thank you for the link. I enjoy seeing what else is out there.

 

[earlene]

It looks like the first calculator @earlene listed defaults to 99% NaOH purity, but allows the user to change the value. The second calculator assumes 100% purity. That variable will affect the calculation as will the superfat/excess fat used to calculate the recipe. If you calculate a recipe with the NaOH at 99% purity and set the superfat to 5% and then switch the NaOH purity to 100%, the calculated amount of NaOH needed for the recipe should go down.

I use the second calculator linked in Earlene’s post. Since I know that the NaOH I use is in the 96%-98% range, I set my superfat to 2%.

I like the calculator for the same reasons Earlene mentioned, but also occasionally experience some quirks when I use it. An example is changes in formatting of the printout if I switch from printing from the main recipe page versus printing from edit mode.

This one also allows the user to adjust lye prity for both NaOH & KOH: LyeCalc

There was discussion of doing that with Soapmaking Recipe Builder (back in May 2020), but apparently did not happen for NaOH. KOH is adjustable by the user, however. (link)

Just as a reference on how to conduct a lye purity test (for those interested), here is a link with further links to a pdf and a video instruction: NaOH or KOH purity check | Soapy Stuff

 

[Shazzer]

Oh thanks for the tips on how test for purity! Very interesting!

Also earlene, unfortunately it's only available in German - that's okay for me, I can speak it, but I do think there are some differences in the way oils are available, for example. That might explain a lot as well!

There is a way to expand the selection of oils; the default view is an abbreviated list. That also took me a minute to find, I was wondering why so many common oils were missing!