How do I modify a recipe when I add or remove an ingredient?

Let’s take a look today at altering recipes as there have been a lot of questions about this lately. (Original post can be found here…)

Let’s say I have this recipe from this post:

SWIFT’S BASIC HAND LOTION FORMULA
69.5% water
15% oil
5% butter
3% cetyl alcohol or stearic acid
6% Polawax
1% fragrance oil
0.5% liquid Germall Plus

Please use the general lotion making instructions for this recipe.

Let’s say I wanted to add a few things to the recipe. I think it might be quite nice to have some glycerin, allantoin, hydrolyzed protein, and panthenol in the mix. How would I add them?

How do I know when to add an ingredient? If they are water soluble and can withstand heat, they would go into the heated water phase. If they are oil soluble and can withstand heat, they would go into the heated oil phase. If they are oil or water soluble and can’t withstand heat, they would go into the cool down phase.

Glycerin, allantoin, and hydrolyzed protein are water soluble and can withstand heat, so they go into the heated water phase. Panthenol is water soluble and can’t withstand heat, so it goes into the cool down phase.

How do I know how much to add to the mix? Check the suggested usage rate, which can be found at your supplier’s website, and trial and error in your workshop. I could add tons of glycerin, but I think I’ll go with 3% because I have found that anything over that tends to feel a bit sticky to me. I know that 0.5% allantoin is a good amount because I’ve used 1% and thought it was a bit gritty. I like to add hydrolyzed proteins at 2% (generally) because that seems to be a nice level that offers some film forming without potential stickiness. And I’ve read that panthenol is effective at 2%. I have found it can get a bit sticky above that level, so I’ll keep it at 2%.

How do I add these ingredients? I would remove the amount of the ingredient from the water portion. So if I’m adding 3% glycerin + 0.5% allantoin + 2% hydrolyzed protein + 2% panthenol = 7.5% new ingredients. I will remove 7.5% from the water amount, leaving me with 61.5% water in this product.

HEATED WATER PHASE
62% water
3% glycerin
2% hydrolyzed protein
0.5% allantoin

HEATED OIL PHASE
15% oil
5% butter
3% cetyl alcohol or stearic acid
6% Polawax

COOL DOWN PHASE
2% panthenol
1% fragrance oil
0.5% liquid Germall plus

If you wanted to remove or add something that is oil soluble, it gets more complicated. Because oil soluble things need to be emulsified, an increase or decrease in an oil soluble ingredients means an increase or decrease in the emulsifier. In this recipe, let’s say you wanted to remove the butter. This means you are losing 5% oil in the recipe. You don’t need as much emulsifier, so you could reduce the Polawax by 1.25%. You would then add 6.25% to the water phase.

All recipes should add up to 100% for ease of reading and formulating. So if you remove something, you have to make it up somewhere. We make it up in the water amount. Yes, this will change the viscosity, but that’s the nature of changing a recipe!

Why did I reduce the Polawax by 1.25%? Because we use Polawax at 25% of the oil phase. Add up all the oil soluble ingredients and multiply by 0.25 to determine how much Polawax we would use. If you are using another emulsifier, you would have to do different calculations.

HEATED WATER PHASE
68.5% water
3% glycerin
2% hydrolyzed protein
0.5% allantoin

HEATED OIL PHASE
15% oil
3% cetyl alcohol or stearic acid
4.75% Polawax

COOL DOWN PHASE
2% panthenol
1% fragrance oil
0.5% liquid Germall plus

I hope this exercise has given you an idea of how to modify your recipes. Please check out the related posts to which I link below if you want more information!

Related posts:
Back to the very basics: Defining our terms for lotions
How do I modify a recipe when I add or subtract an ingredient?
Learning how to read and convert a recipe
Newbie Tuesday: Let’s make a lotion!
Making your first lotion (PDF)