Saturday, March 7, 2015

Weekend Wonderings: More information on calculations

In this post, Question: Determining how much to use when working with powders, there's a discussion going on about calculations. Let's take a look at a few calculations today!

68.5% water
16% oil (sunflower, soy bean, rice bran, or olive oil)
5% shea or mango butter
3% cetyl alcohol
6% emulsifier (BTMS or Polawax)
1% fragrance or essential oil
0.5% liquid Germall Plus

When you are making a product, the recipe should total 100%. I know some of my recipes don't total 100%. Why is that? Sometimes it's because I'm trying to account for different preservatives having different usage amounts. Liquid Germall Plus calls for 0.1% to 0.5% usage, while Germaben II calls for up to 1% usage, so my recipes might say 0.5% to 1%, totalling 100.5%.

A recipe should not vary between weight and volume measurements. For instance, we don't want to see 5 grams of this and 4 ml of that. We want everything in grams or ounces (preferably grams as that's easier to convert from percentages).

To convert a recipe, trade the % sign for the word "grams" and you will get a recipe that weighs 100 grams.

If you want to make half the recipe, then divide everything in the recipe by 2 to create a 50 gram batch. For the lotion above, you'd have 34.25 grams water, 8 grams oil, and so on.

If you want 25 grams of the above recipe, divide everything in the recipe by 4 and get 17.125 grams water, 4 grams of oil, and so on.

If you want to make double the recipe, then you'd multiply everything in the recipe by 2, so you'd have 137 grams water, 32 grams oil, and so on.

Have fun formulating!


James Holman said...

I wish everyone would start using metric measures. It gets old having to convert from ounces to grams.

Thanks for all your great info. I love the simple lotion recipe. -James

ChrisB from the Dish said...

Hi Susan, not sure where to put this question... figured a post on lotion was a good spot!

I was just wondering what oils/butters you recommend adding to a lotion to make the lotion last longer on the skin. I have tried many of your formulas (love a few of them) but after about two hours, the moisturizing effect is gone and my legs are flaky again. Are there any oils in particular I should be using?

Thanks! I love your blog and very much appreciate your sharing so your knowledge and experience.

Susan Barclay-Nichols said...

Hi ChrisB! I've tried to answer your question in today's Weekend Wonderings.

Michelle Venable said...

Hi. I'm a newbie and have put together a mixture of aloe, macadamia, jojoba, olive (98.6% of these) and 1.4% essential oils for dehydrated facial skin. The aloe that I have is very liquid as opposed to a gel, and so my mixture is very thin and watery. Is there some sort of emulsifier (that is also organic) that I can add at this point to thicken? ... It's a gift for a friend who prefers organic as much as possible. Thank you for your suggestions.

Susan Barclay-Nichols said...

Hi Michelle. No, there is no such thing as an organic emulsifier. You can get Ecocert ones, like Ritamulse SCG, but then you're making a lotion at that point. You're better off leaving out the aloe or getting aloe oil, aloe butter, or oil soluble aloe that will mix better.