HLB system: A demonstration (part 2)

Let's choose a few more lotion recipes and see how we can use the HLB system to make our own emulsifiers! Let's go with an easy one first - the six ingredient lotion for my husband's itchy skin!

SIX INGREDIENT LOTION WITH SHEA, SOY BEAN, AND SESAME OIL
HEATED WATER PHASE
39.5% water
20% aloe vera
3% glycerin

HEATED OIL PHASE
10% refined shea butter
10% soy bean oil
10% sesame oil
6% BTMS-50

COOL DOWN PHASE
0.5% liquid Germall Plus
1% fragrance oil (Clementine Cupcake)

Remember the steps to finding out the HLB value of your ingredients.

1. Which ingredients have an HLB value?
2. How much of each ingredient is in the total recipe?
3. Divide this by the total oil phase to get a percentage.
4. Multiply the percentage by the HLB value. Add them together to get the HLB value of your oil phase.

1. Which ingredients in this lotion have an HLB value?
We have three ingredients with an HLB value - the shea butter (8), soy bean oil (7), and sesame oil (7).

2. How much of each ingredient is in the total recipe?
10% shea butter
10% soy bean oil
10% sesame oil
Total oil phase = 30%
Remember to leave out the original emulsifier as we are trying to replace that!

3. Divide this by the total oil phase to get a percentage. 
My total oil phase is 30%.
shea butter - 10/30 = 0.333
soy bean oil - 10/30 = 0.333
sesame oil - 10/30 = 0.333

All right, I know this actually equals 99.99999% so let's round one of the oils up to 0.34 and leave the rest at 0.33 and be done with it! I'll round the sesame oil to 0.34 so we have...
shea butter = 0.33
soy bean oil = 0.33
sesame oil = 0.34

4. Multiply the percentage by the HLB value. Add them together to get the HLB value of your oil phase.
shea butter - 0.33 x 8 = 2.64
soy bean oil - 0.33 x 7 = 2.31
sesame oil - 0.34 x 7 = 2.38
Total is 7.33. So our required HLB for this lotion is 7.33.

The steps to finding out the HLB value of your emulsifiers.
1. Find a low HLB emulsifier and a high HLB emulsifier.
2. Work on the percentages to find a total that is very close to the HLB value of your oil phase.
3. Rejoice!

1. Find a low HLB emulsifier and a high HLB emulsifier. 
Let's go with glycol distearate (HLB 1) and ceteareth-20 (15.2) for our emulsifiers.

2. Work on the percentages to find a total that is very close to the HLB value of your oil phase. 
50% glycol distearate = 1 and 50% ceteareth-20 = 7.6. Total = 8.1. Too high!
40% glycol distearate = 0.4 and 60% ceteareth-20 = 9.12. Total = 9.52. Too high!
60% glycol distearate = 0.6 and 40% ceteareth-20 = 6.08. Total = 6.68. Too low!
55% glycol distearate = 0.55 and 45% ceteareth-20 = 6.84. Total = 7.39. Close enough!

So we know we need to use 55% glycol distearate and 45% ceteareth-20 as our emulsifier.

If we're using 4% emulsifier in this product (again, this is kind of a random number I've chosen as there isn't a rule of thumb for HLB emulsifiers), then we need 2.2% glycol distearate (4% x 0.55) and 1.8% ceteareth-20 (4% x 0.45) in our recipe.

Remember, when you decrease the oil phase, increase the water phase by the same amount!

SIX INGREDIENT LOTION WITH SHEA, SOY BEAN, AND SESAME OIL MODIFIED TO USE HLB EMULSIFIERS
HEATED WATER PHASE
41.5% water
20% aloe vera
3% glycerin

HEATED OIL PHASE
10% refined shea butter
10% soy bean oil
10% sesame oil
2.2% glycol distearate
1.8% ceteareth-20

COOL DOWN PHASE
0.5% liquid Germall Plus
1% fragrance oil (Clementine Cupcake)

Now comes the rejoicing! Yay!

I'm posting a recipe in a few minutes so you can practice the HLB system on your own! Have fun!