Is SoapCalc for Hot or Cold Process?

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Techie Joe

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I have read that Hot and Cod processes use up different amounts of water during making, how can we account for this in SoapCalc?
How would we know about the difference in evaporation rates, etc?
Is there a general guide / rule of thumb that we can follow for hot and cold?
 

The Efficacious Gentleman

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People generally use the default water amount in the calcs when doing hp, but change it for cp. It is a bit of a trial and error process, of course, as even for hp how you do it as well as your recipe and your particular equipment will have an impact on the final batter
 

Techie Joe

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Thanks gent and dixiedragon, same for both hot and cold.
I know there are a lot of variables especially in HP so its a complex question.
 

dixiedragon

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It's complex in that you can do a lot of different things to get different results, but simple in that if you stick with the default, your soap will be fine. I've been soaping for more than 15 years and I just now started playing with different water amounts.
 

SaltedFig

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I agree there is nothing wrong with using the default amount of water, usually, but it can lead to odd results in some (less common) soaps (like significant warp in CP olive soaps due to excess water, which I discovered very early on, due to the recipes I was making).

If you get into the habit of using the lye concentration or water:lye ratio from your first soaps, later adjustments to the water amount are easy to calculate and the impact of changes to the lye concentration become predictable, even when different oils (recipes) are used.

For your extra hot method of HP (up to 213F measured at the surface, at one point in the video!), I would expect that you need to add some water to the recipe, to account for evaporative loss.

With the CP and SVHP comparison recipes that I've made, no change to the water in the recipe is necessary (near zero evaporation). I have used about 33% lye concentration (or roughly 2 parts water to 1 part NaOH) for both methods.

So it is very method dependent, with HP potentially (but not always) needing more water.

A way to know how much water has evaporated, is to weigh your soapmaking equipment (pot, tools) at the start and finish of soaping, and record the difference.
Do the same with your molds, weigh them at the start and after your soap is in the mold, and record the difference.

The amount of "waste batter" is the difference in your tool weights.
The "molded soap weight" is the difference in your mold weights.
The waste batter and molded soap weight added together is your total soap weight.
The weight difference between the original recipe amount and the total soap weight is the amount of water that has be lost to evaporation.

When you know how much you water you have lost to evaporation, you can convert that to an evaporation percentage (the percentage of water you expect to lose during the cook), and from this you can make your recipe in CP and be able to predict the necessary adjustment to the water amount.

This comes in particularly handy if you are taking a CP recipe and converting it to your HP process - you will know how much extra water to add.
 

IrishLass

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The way to adjust your water on SoapCalc is to use the "Lye Concentration" box. SoapCalc is my go-to calculator, but I completely ignore their default "Water as % of Oils" box and head right over to their "Lye Concentration" box instead (water based on the lye amount instead of the oil amount). Figuring water based on the lye amount provides one with much more consistent, reliable control over how batches proceed and also how they turn out, whether making HP or CP.

While SoapCalc's default is fine for HP because it gives you a 'full water' amount, which is what you need to keep your HP batter from becoming too dry and unmanageable during the cook, it would be remiss of me not to mention that it can cause some undesirable issues with CP soap depending on your formula ( see our DeeAnna's treatise on her blog here, and also this discussion we all had here ).

I find that having less water in my CP works out much better for me (it prevents warping in my bars during cure, I can unmold/cut much faster, there's less chance of overheating, separation etc...). My favorite go-to lye concentration for most of my CP batches is 33%, and my favorite lye concentration for my HP batches is 29%.


IrishLass :)
 

earlene

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I used SoapCalc first when I started soaping using HP, and had no difficulties. Being new, I was using only the default settings, which are considered 'full water' settings, and those work fine for HP.

When I started doing CP, I still used the default settings until I learned about changing to lye concentration. Around that same time I also started using the lye calculator at Soapee.com more often than SoapCalc.

But I have used some of the others, and all of them (that I have used) when using the default settings work fine for HP, IMO. It's been so long since I used some of them, I went looking just now and see that both the Summer Bee Meadow and the MMS at the Sage calculators have been updated. I found them useful for some things, but more work than I wanted to do for most things.

As far as the difference in evaporation rates, I think after the soap starts curing there is none. Evaporation should occur at the same rate, I assume, based on environment and composition of the particular soaps. So if I make the same soap recipe in two batches, one HP and one CP, once the soaps are out of the molds, cut and on the curing racks, I would expect them to evaporate at approximately the same rate. The only difference I would foresee would be if one has less liquid by the time it is out of the mold.

I do believe I have read more than once, somewhere something about how to calculate or estimate water loss, but don't quite remember where that was. But you could test it out by doing a side-by-side experiment and weigh the soaps every week (or daily, if you prefer) until they stop loosing weight and see how the water loss rates compare.

ETA: Here are a couple of threads that address water loss rates during cure:
https://www.soapmakingforum.com/threads/cure-time.35831/
https://www.soapmakingforum.com/threads/degree-of-shrinkage-during-cure.34604/
https://www.soapmakingforum.com/threads/water-reduction-and-cure-times.38161/
 
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msunnerstood

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I use the brambleberry lye calc for HP and depending on how often you open the lid and stir, you can lose more water than you like, I just add a tablespoon ere and there if it happens and never had an issue.
 
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