Thursday, February 10, 2011

Learning to formulate: A note about percentages

To clarify, when you're creating any product, think in percentages, not grams or volume. When making any product, you'll want the total ingredient list to come to 100% (mine vary because I'm thinking about other preservatives you might want to use, but 100% is the ideal). If you look at the recipes on this blog or in the e-books, any recipe from our suppliers, or any recipe on a forum, it should total 100%. This is because doing it in percentages makes it easier to see if we have our ingredients in the right amounts, switch ingredients for others, and change our phase amounts. Plus most of our ingredients come with the suggestion to use them at some% to another%, so there's no down side to thinking in percentages.

So when I'm talking about increasing the oil phase or decreasing the water phase, I'm talking about the percentages those phases make up in the lotion. If we have a 69.5% water phase and a 29% oil phase, but want to increase the oil amount to 40%, we'll have to decrease our water phase by 11% to keep that 100% total at the end.

Percentages make life easier when you're formulating. Let's say you have a recipe and want 250 grams of it. Then multiply all the numbers by 2.5 to get your new amounts. If you want to make a 1000 gram batch of lotion, then multiply all the numbers by 10. If you want a 50 gram batch, divide all the numbers in half (not so useful for lotions, but great for lip balms or lotion bars).


Heidi said...

Hi Susan

If your not a teacher, you SHOULD be!

Plus your sense of humor! The kids would love ya.

I am learning so much thanks to the hard work you put into your blog.

Heidi said...

Oh, I did have a question.

I made the solid shampoo bar. Came out great....except I guess I am just too much of an oily haired girl. I have always washed my hair everyday, but with the shampoo bar by nightfall my hair is oily.

I cannot get the sci without stearic acid. So I was thinking of just either making it like a clarifying bar and/or make slsa a higher percentage then the sci.

What do you think?

I will be trying out another batch as soon as my essential oils arrive.

Thanks Susan!

sfs said...

The Herbarie has sci flakes without stearic acid.
Where are you buying it with?

sfs said...

Sorry, I don't know how to make a click-on link. :(

Heidi said...

Thank you SFS!

I did contact them today. (That is where I bought it) They said that their sci is 85%active and the rest filler. She wasn't quite sure but thought it contained stearic acid.

She also didn't think the stearic acid shouldn't contribute to making hair greasier.

Maybe I just need to cut out the conditioners in this bar. I just couldn't believe how oily my hair was at night.

I do have a scale and weighed out things correctly.

Here is what I used for a 6oz size:

SCI flakes : 51.029g (30%)
SLSa : 51.029g (30%)
DLS mild: 25.5145 g (15%)
cocamidopropyl betaine 17.009g (10%)
cetyl alcohol 5.1029g (3%)
BTMS 50 5.1029g (3%)
mango butter 3.4019g (2%)
incroquat cr concentrate 3.4019g (2%)

hydrolyzed wheat protein 1.70097g (1%)
panthenol 1.70097g (1%)
dimethicone 1.70097 g (1%)
rosemary & peppermint essential oils
3.4019g (2%)

(I didn't use preservative in this, but plan to on the next one)

Susan Barclay-Nichols said...

Hi Heidi. Thanks for the kind words. I did train to be an English/Canadian studies teacher but I couldn't afford to not work for the year of student teaching and besides, no one was hiring during the last big recessions. So with my liberal arts degree I became a social worker (the government was low on those and hiring anyone with a degree at the time).

I don't think the issue is necessarily the stearic acid in the SCI - although I find it makes my hair greasier. I think it might be all the conditioning agents in your bar. You have both BTMS-50 and Incroquat CR - choose one (I'd go with the CR as I've not notice a huge difference in using BTMS and CR is cheaper) - and cut out the cetyl alcohol. You already have stearic acid in the bar as a thickener, so you don't need the cetyl alcohol (except to boost up the conditioning power, but I think that's what's going wrong here). You can even cut out the mango butter - it's probably not necessary as you already have enough natural oils in your hair! I'd just use the Incroquat CR and dimethicone as the conditioning agents in this product. You don't need much. If you're using this without a follow up conditioner, you might consider using a cationic polymer, like polyquat 7 or honeyquat, as a conditioning agent that won't add more emollients in the form of fatty alcohols or acids to the product. You can make up for the difference in what you remove with SCI or SLSa, but don't add any more liquid ingredients.

Thanks for the information, sfs. I've had such a busy week, this is the first time I've been able to look at the comments!

I get my stearic acid free SCI at Aquarius Aroma & Soap in B.C. but you can get it at the Herbarie as well.

Heidi said...

Thanks for the reply, Susan.

I'm one of those girls with oily scalp but dry ends. Hmmm, could be because I color my hair and it is sorta long.

I made up your conditioner bar and just tweeked it a little. LOVE IT so far!

I hear ya about not being able to take off the year without pay. Well you never know what the future holds and so long as you love what you do that's great. But you can tell from your blog your a natural born teacher.

A'nnamaria Davis said...

I'm new to soaping, basically every thing is new to me, but what I'm interested in making Body spray or body perfume, looking for recipes and learning how to formulate my own recipes. Learning amounts of persevatives to use is there any books that you have that will help me to learn how to calculate and be able to make body spray Thank A'nnamaria

Susan Barclay-Nichols said...

Hi A'nnamaria! Did you do a search on the blog for those recipes? I have quite a few.