HLB system: Let's get slightly more complicated

The one down side of using the HLB system is that you have to figure out the HLB of the oil phase if you change an ingredient (unless you're substituting one vegetable based oil for another one, but even then jojoba could throw you off because it's 6.5, fractionated coconut oil is 5.5, and emu oil is 8, although that's not a vegetable oil, is it?).

The other down side is that it's hard to find information for some of our esters. There's some great information in the PDF to which I keep referring (and you really should have downloaded by now if you want to play along). So let's take a look at what happens when we take a recipe - let's use yesterday's - and mess with it by changing the oils, adding some esters and silicones, and adding some fatty alcohols. (This won't be considered minimally processed for much longer!)

BODY BUTTER FOR ITCHY WINTER SKIN WITH MINIMALLY PROCESSED INGREDIENTS
WATER PHASE
25% water
10% aloe vera
10% chamomile hydrosol
10% witch hazel
2% hydrolyzed protein
5% tamarind seed extract
3% glycerin
0.5% allantoin

OIL PHASE
10% soy bean oil
7.5% cocoa butter
7.5% mango butter
7% emulsifier*

COOL DOWN PHASE
0.5% chamomile extract
0.5 to 1% preservative
1% fragrance or essential oil blend

Let's say you want this to be a drier feeling body butter. We'll keep the 7.5% mango butter (HLB 8), but let's add a few esters to the mix. I think I want some isopropyl myristate at 2% (HLB 11.5) and I'll add 3% cetyl alcohol to thicken the product (since I took out the cocoa butter, it will be thinner), which has an HLB of 15.5. I think I'll include 5% C12-15 alkyl benzoate (HLB 12) and 5.5% cetearyl ethylhexanoate (HLB 8.22). And finally, I think I'll go with dimethicone at 2% in the cool down phase (it's listed as 5, but there's some debate about this. Click on this post for more information).

Okay, so where are we? We didn't change the amount of the oil phase - it's still 25% of the total recipe (we don't include the emulsifier because we're trying to replace that) - but we've changed the HLB dramatically!

Remember the steps to finding out the HLB of your oil phase...

1. Which ingredients have an HLB value?
Mango butter, isopropyl myristate, cetyl alcohol, C12-15 alkyl benzoate, cetearyl ethylhexanoate, and dimethicone.

2. How much of each ingredient is in the recipe?
Mango butter - 7.5%
IPM - 2%
Cetyl alcohol - 3%
Dimethicone - 2%
C12-15 alkyl benzoate - 5%
Cetearyl ethylhexanoate - 5.5%
Total oil phase = 25%

3. Divide the amounts by the total oil phase to find out how much each makes up in the oil phase.
Mango butter - 7.5/25 = 0.30 or 30%
IPM - 2/25 = 0.08 or 8%
Cetyl alcohol - 3/25 = 0.12 or 12%
Dimethicone - 2/25 = 0.08 or 8%
C12-15 alkyl benzoate - 5/25 = 0.20 or 20%
Cetearyl ethylhexanoate - 5.5/25 = 0.22 or 22%

4. Multiply the percentage by the HLB value. Add them together to get the HLB value of your oil phase.
Mango butter - HLB 8 - 0.30 x 8 = 2.40
IPM - HLB 10 - 0.08 x 10 = 0.80
Cetyl alcohol - HLB 15.5 - 0.12 x 15.5 = 1.86
Dimethicone - HLB 5 - 0.08 x 5 = 0.40
C12-15 alkyl benzoate - 0.20 x 13 - 2.60
Cetearyl ethylhexanoate - 0.22 x 8.22 = 1.8084

So the required HLB of this oil phase is 9.8684.

1. Find a low HLB emulsifier and a high HLB emulsifier.
I'll go with glycol distearate (HLB 1) and ceteareth-20 (HLB 15.2) for one combination and glyceryl stearate (HLB 3.8) and oleth-10 (HLB 12.4) for another.

2. Work on the percentages to find a total that is very close to the HLB value of your oil phase.

GLYCOL DISTEARATE AND CETEARETH-20

50% glycol distearate (0.5) + 50% ceteareth-20 (7.6) = 8.1. Too low.
40% glycol distearate (0.40) + 60% ceteareth-20 (9.12) = 9.52. Still too low.
38% glycol distearate (0.38) + 62% ceteareth-20 (9.424) = 9.804. Close enough!

If we're using 4% emulsifiers in this recipe, we'll need to use 1.52% glycol distearate (4% x 0.38 = 1.52%) and 2.48% ceteareth-20 (4% x 0.62 = 2.48). If we want to use 5% emulsifiers in this recipe, we'll need to use 1.9% glycol distearate (5% x 0.38 = 1.9%) and 3.1% ceteareth-20 (5% x 0.62 = 3.1%).

GLYCERYL STEARATE (HLB 3.8) AND OLETH-10 (HLB 12.4)
50% glyceryl stearate (1.9) + 50% oleth-10 (6.2) = 8.1. Too low. 

40% glyceryl stearate (1.52) + 60% oleth-10 (7.44) = 8.96. Still too low!
30% glyceryl stearate (1.14) + 70% oleth-10 (8.68) = 9.82. Just about right! 

If we're using 4% emulsifiers in this recipe, we'll need to use 1.2% glyceryl stearate (30% of 4% is 1.2 - 0.3 x 4 = 1.2) and 2.8% oleth-10 (70% of 3% is 2.8 - 0.7 x 4 = 2.8). 

If you want more practice, try figuring out how you'd use something like PEG-100 stearate (HLB 18.8) and glycol distearate (HLB 1) or polysorbate 80 (HLB 15) and glycol distearate (HLB 1) or any other combination of high and low HLB emulsifiers! 

What does our recipe look like now? (And remember to increase your water amount if you've removed anything from the oil phase. We took out 2% of the previous emulsifier, so we need to increase the water to 27%). 

BODY BUTTER FOR ITCHY WINTER SKIN WITH NOT-SO MINIMALLY PROCESSED INGREDIENTS USING HLB EMULSIFIERS

WATER PHASE

27% water

10% aloe vera

10% chamomile hydrosol

10% witch hazel

2% hydrolyzed protein

5% tamarind seed extract

3% glycerin

0.5% allantoin

OIL PHASE

7.5% mango butter

2% IPM

3% cetyl alcohol

5% C12-15 alkyl benzoate

5.5% cetearyl ethylhexanoate

5% emulsifier (1.9% glycol distearate and 3.1% ceteareth-20 or 1.2% glyceryl stearate and 2.8% oleth-10)

COOL DOWN PHASE

2% dimethicone

0.5% chamomile extract

0.5 to 1% preservative

1% fragrance or essential oil blend

Join me tomorrow for one more post on HLB emulsifiers before we get back to duplicating!