Whipped Soap Volume Differential?

To what degree does the volume of your soap increase when you make whipped soap compared to standard cold process with the same weights of fat?


Bear with me as I try to communicate this thought clearly without typing an essay.

I want to try whipped soap.

Making whipped soap incorporates air into the fats, resulting in a greater volume of soap from a given weight of ingredients. This creates a bit of a practical issue in terms of selecting a mold. Using two pounds of fats in a whipped soap recipe would definitely overfill a two pound mold. I understand that how much so would depend on a number of variables specific to your individual recipe and methodology.

In the interest of learning through others' experience, I am hoping a few of you can give me an idea of how much the volume increases by. Half again as much? More? Less?

I plan to use a bigger mold, but like playing with designs. Making a more informed decision on which size to use would help me plan for a better outcome. I would hate to scramble for additional options if a mold is insufficient or end up with shallow, pygmy bars because I overestimated my needs.

If one of you happens to have bars of whipped and standard cold process lying around... The dimensions and weights would allow me to do a bit of math for my answer :smile:

Thanks in advance for any help.

Have you seen this sticky? http://www.soapmakingforum.com/f11/how-figure-how-much-oil-mold-2909/

There is an increase in volume but I never paid attention to exactly how much of an increase. I normally use individual cavity molds for whipped soap and I like having extra to pour into smaller cavity molds to use as test soap, novelty soap and embeds.

I know the whipped soap batches I've made have not doubled in size during whipping. I'm guessing at most there might have been increase of about 25% but I doubt it was even that much. I know I've never thought any increase was exceptional. BTW, I use a hand mixer so this might make a difference as compared to a stand mixer. Also, I've never used lard or tallow in whipped batches which might make a difference with an increase in volume.

I can't even tell you of any comparisons between whipped and CP because the batches I've used in cavity molds are gone and I don't remember how many bars and small soap I got from them. (Note to self: start writing down how many bars from each each batch.) The batch I recently made was really small since I just wanted embeds - only 16 oz of oil and 4.5 oz of water. I used 2 paper towel cores for tubes and the soap didn't quite fill the tubes. However, this is partly due to seepage from the bottom since I did a bad job of taping off the bottoms of the freezer paper. So, it's possible the batch would have filled the tubes if it wasn't for this reason. I don't know if this info will help you.

Hazel said:

Have you seen this sticky? http://www.soapmakingforum.com/f11/how-figure-how-much-oil-mold-2909/...

I know the whipped soap batches I've made have not doubled in size during whipping. I'm guessing at most there might have been increase of about 25% but I doubt it was even that much. I know I've never thought any increase was exceptional. BTW, I use a hand mixer so this might make a difference as compared to a stand mixer. Also, I've never used lard or tallow in whipped batches which might make a difference with an increase in volume.

Click to expand...

This is incredibly helpful. If I understand the original poster, they did the math to get a conversion factor for the volume of the mold to the WEIGHT of the oils based on the density of cold process soap. If that is the case, the lighter density of whipped soap would not conform to the equation.

I had not yet seen that sticky and worked out a cubic inches/liquid oz volume conversion. Once I have made the "batter", multiplying the number of fluid ounces by 1.805 should give me the number of cubic inches need to contain my soap. Conversely, multiplying the cubic inch volume of my mold by 0.554 should tell me how many fluid ounces that mold can hold. The conversion factor is helpful to verify that I am not shooting myself in the foot before pouring, but still requires me to pick my mold once the batter is ready.

That would be fantastic if I had a large assortment of shapes and sizes to choose from. However, I am a newbie that is simply making soap for myself and friends. As such, I am constructing soap molds as I need them for the volume and color effect that I want to try. I hate to waste soap by making more than I need to ensure that I can fill a mold, or build a mold that is ridiculously oversized for my needs.

I do not plan to use any lard or tallow either, but do have a stand mixer. I will try building a mold of base dimensions that I like with a height that gives me 50% more space to expand (i.e.- 3lb mold for 2lb recipe) to err on the safe side. This should solve the problem and can serve as an alternate shape for any future 3 lb batches of CP.

Once again, your experience is invaluable and should allow me to skip a couple of mistakes along the learning curve. I hope I din't make your eyes glaze over when I started talking "geek".:smile:

I should have clarified that if you calculated how much CP for a mold it might give you a rough idea of how much for whipped. Calculate an amount and then add approximately 25%. Also, I thought someone had mentioned volume conversion later in the discussion. I may be wrong since it's been a long, long time since I read it.

You don't need special molds to hold extra. People have mentioned using food containers which show PP#5 on the bottom as spare molds.

Thanks again for taking the time to enlighten me. Your information was very helpful. I am confident enough in my approximations now to cut wood and throw together my new molds. I tend to overcomplicate things and jump straight past the basics (why use two colors when you can use six mentality). Therefore, I like to carefully preplan everything to death. I prefer theoretical troubleshooting to compensating for my oversights on the fly.

Hopefully my designs, recipes, scents, and colors will all translate into approximations of what I envisioned.:-D

You're welcome! Whipped soap is easy even if a little more time consuming than making CP. I know a nephew and a niece think it's fun that it floats in water. There's nothing wrong with carefully planning ahead especially if it involves cutting wood.

I hope it works out for you and don't forget to post pics. :grin: