How to Re-size a Cold Process Soap Recipe
I’ve had several people request a smaller sized cold process recipe for some of my most popular homemade soap recipes. However, as when I started making many of these specific soap recipes I had created, I always made larger batches to keep up with the demand from where I was selling at my local farmer’s market as well as Etsy. I’d never considered having to re-size a batch of cold process soap before. However, the solution is pretty simple.
Bramble Berry’s lye calculator includes a tool that allows you to re-size any batch of soap. Simply plug in the existing recipe, choose the superfatting level and hit calculate. Then below the current batch label, simply choose re-size batch and enter in the size of batch you want to create! If you’re not sure what percentage the recipe was superfatted to, you can play around with the numbers until they’re close. (I typically use around 6% superfat.)
Pictured above is screen shot of the results from plugging in my Best Ever Big Lick Salt Bar Soap Recipe. This particular recipe fills three of my soap molds and yields approximately 30-36 bars depending on how large they are cut.
As each one of my molds can hold a recipe with 36 oz. of oil, I plugged in 36 oz. under “resize batch” and then submitted the new information. It instantly converted the previous recipe to the smaller size with the new amounts needed. This new recipe will now fill just one of my soap molds instead of three and yield 10-12 bars of soap. (I tend to round up or round down the water amounts.) So for this recipe I would use 5 oz. of lye and 12 fluid ounces of water.
As this re-sized recipe is exactly one third of the larger sized batch, you would then divide the amounts for the fragrance oil and salt by 3. Therefore you end up using 2 oz. of fragrance oil. As the recipe calls for 1/2 cup of large sea salts, you would need to divide that by 3 as well. The easiest way to do this is to convert the 1/2 cup into Tablespoons. 16 Tablespoons equals one cup. So a half cup is the equivalent of 8 Tablespoons. 8 divided by 3 equals 2.6 Tablespoons. Therefore I would use 2 1/2 Tablespoons of salt. Or 2 Tablespoons and 1 1/2 teaspoons. (You can reference the original recipe and tutorial here.)
I hope this helps those of you just getting started out and in need of a little assistance. Math skills come in super handy when making soap. I’m constantly figuring percentages of oils I want to use in my new soap recipes. For more help with soapmaking as well as creating your own unique soap recipes, I highly recommend Susan Miller Cavitch’s book, The Soapmaker’s Companion. It was the first soapmaking book I ever purchased and the information has been invaluable.