Saturday, July 19, 2014

Weekend Wonderings: Adding and removing from the water amount

When we're adding or removing water soluble ingredients from a recipe, we tend to remove or add to the amount of water in the product.

Let's say we have a recipe that looks like this....

BASIC LOTION RECIPE
HEATED WATER PHASE
74% water

HEATED OIL PHASE
20% oil
5% emulsifier

COOL DOWN PHASE
1% preservative

...and we want to add 0.5% allantoin, how do we modify the recipe? We add the allantoin and remove some of the water.

HEATED WATER PHASE
73.5% water
0.5% allantoin

What do we do if we want to add glycerin at 3%?

HEATED WATER PHASE
70.5% water
0.5% allantoin
3% glycerin

What if we want to add 2% hydrolyzed protein, 1% fragrance oil, 0.5% green tea extract, and 2% panthenol, as well as the 3% glycerin and 0.5% allantoin? (2+1+0.5+2+3+0.5=9).

HEATED WATER PHASE
65% water
3% glycerin
2% hydrolyzed protein
0.5% allantoin

COOL DOWN PHASE
1% fragrance oil
2% panthenol
0.5% green tea extract
1% preservative

When we add or remove water soluble ingredients into a recipe, we remove water from the water amount. Why do we do that?

We want our recipes to total 100%. It makes it easier to add and remove things, to see how much we should be using of things, and to modify the recipe. (If the recipe is over 100%, it's not the end of the world, but it's not the best idea!) Let's say we know we can use up to 0.5% of something in a recipe; having the recipe in percentages totalling 100% makes it easier to add that ingredient to the product. Just add it at 0.5%. (If your recipe totals 120%, how much do you add now? See, it's easier to use 100%.)

Related posts:
How do I modify the recipe when I remove or add something?
Learning to formulate: The water phase
Learning to formulate: A note about percentages
What happens if the recipe totals more than 100%?

This rule is for water soluble ingredients. So what do we do if we want to include more oil soluble stuff? Well, that's a bit trickier, but you can do it!

HEATED OIL PHASE
20% oil
5% emulsifier

Let's say we want to add 3% cetyl alcohol to the product to thicken it up. Then we would add 3% cetyl alcohol and remove 3% from the water amount...WAIT! STOP! Don't we have to do something else? Why yes, yes we do! We have to increase the amount of emulsifier in the product as well. So let's say we're using Polawax, which has a suggested usage rate of 25% of the oil phase.* We have to increase the emulsifier by 0.25% for every extra 1% of oil soluble ingredient we add. In this case, it means we have to increase the Polawax by 0.75%. We are adding 3.75% to the oil phase (3% cetyl alcohol and 0.75% emulsifier), so we need to remove 3.75% from the water phase.

*This is only a rule for Polawax. Every other wax has its own usage rules. For instance, e-wax NF is generally used at 1% more than Polawax. In this case, you'd be using 6.75% e-wax NF.

HEATED WATER PHASE
70.25% distilled water

HEATED OIL PHASE
20% oil
5.75% emulsifier
3% cetyl alcohol

Let's say you wanted to add 2% dimethicone and 2% cyclomethicone to the cool down phase, along with 1% Vitamin E and 1% fragrance or essential oil. We have a total of 6% oils that are to be added to the product. If we are using Polawax at 25% of the oil phase (0.25% for every 1% of oil used), then we have to add 1.5% Polawax to the mix, for a total of 7.5% extra oil to the product. We would remove 7.5% from the water.

HEATED WATER PHASE
62.75% distilled water

HEATED OIL PHASE
20% oil
7.25% emulsifier
3% cetyl alcohol

COOL DOWN PHASE
2% dimethicone
2% cyclomethicone
1% Vitamin E
1% fragrance or essential oil
1% preservative

Yep, when we add things like fragrance or essential oils, we have to increase the emulsifier. I don't generally do this as the increase of 0.25% emulsifier when I'm adding 1% fragrance or essential oils isn't going to make a huge difference. Besides, given that I'm measuring in 1 gram increments, I'm sure I have a little extra in there any way!

Join me tomorrow for more Weekend Wonderings!

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