Friday, August 12, 2011

The great conditioner experiment: Modifying the recipe!

I've been agonizing over this post for a few days now over this recipe because my original recipe adds up to 105 grams, so if I add 50 grams of water and 0.25 grams of preservative, the grand total of the product will be 155.75. So I could just leave the recipe as is and recognize that it will equal 155.75 grams every time I make it - or I could figure out the percentages!

There's nothing wrong with having a recipe total more than 100% and you can multiply each ingredient to make larger batches if you want, but the standard is to work with weighed ingredients and have your recipe total 100% (a part of this is so the formulators can write "water q.s,", add enough water so the total of the recipe is 100%. If your recipe can total 105% or 112%, then you won't have added enough water!).

If you want to figure out the percentage, divide the amount of each ingredient by the total this...

123.50 grams of water = 123.50/155.75 = 79.2%
2 grams of hydrolyzed protein = 2/155.75 = 1.18%

and so on, resulting in some really annoying numbers like 1.9261637239165% Incroquat CR and 0.3% preservative. I know I want to have 0.5% preservative (maximum usage for liquid Germall Plus) and 1% fragrance, so those numbers need to be rounded up so others must be rounded down.

When I finally worked on the the recipe this is what I found...

79% water
1.3% hydrolyzed protein
1.3% cetrimonium chloride

4.5% Incroquat BTMS-50
2% Incroquat CR
2.6% cetrimonium bromide
2.6% ethylhexyl palmitate

1.3% panthenol
1.3% dimethicone
1.3% cyclomethicone
1.3% dimethicone
1.3% polyquat 44
1% fragrance oil
0.5% preservative

My recipe totals 100% and all is well. It's a pain to work with 1.3 grams or 0.5 grams so here are my suggestions - get a small scale that can weigh down to 0.1 grams or make larger batches. I never make less than a 10 times batch (1 kg) when I'm using a recipe I know I'll use a lot and want to store, like liquid conditioner, leave in conditioner, body wash, and so on. If I were to make this recipe for the first time, I'd make a small batch so I wasn't wasting supplies if I hated it!

As a note, if you want to make a small batch but don't have a small scale, you could multiply this recipe by 3 to make all those 1.3% turn into 4% (well, 3.9% but close enough!) and the 2.6% turn into 7.8%, which you could round up to 8%.

How did I know to multiply by 3 to get a rounder number? I don't know the name for it, but it seems logical that if we have something like 1.3 and 2.6, if we multiply by 3, we'll get a number we can round up to being a whole number. I've been looking for the mathematical explanation, but I can't find it. I just know that multiplying by 3 or a multiple of 3 will work well. 

If you're still a little intimidated by the math, click here for my post on not fearing math, then move on to this post on calculating percentages from weights and this one on converting from percentages to weight.

Join me tomorrow for more formulating fun!


Tara said...

I think the term you are looking for is the Lowest Common Denominator. 3 is the lowest common denominator of 3 and 6 (3 x 1 = 3 and 3 x 2 = 6).


Steph said...

I was wondering where you find the hyd. protein at? I was looking online and it kept on bringing up like protein mixes for protein drinks and such is this what I should order? i live in the USA

Susan Barclay-Nichols said...

Hi Tara! Thanks! My math escaped me there!

Hi Steph. If you look to the right hand side of the page, you'll see a listing for hydrolyzed protein. Click on it to learn more about this ingredient.

Anonymous said...


Your blog is simply amazing, I have learned so much. I do have a request, or maybe a suggestion. Have you ever thought of dabbling into facial masks?

Susie said...

Hi Susan,
I was looking at trying your super conditioner recipe, should the second 1.3% dimethicone read as 1.3% cationic polymer as per your previous conditioner recipe from the day before.