Sunday, February 20, 2011

Learning to formulate: Small changes make big differences in the water & cool down phases

Yesterday we took a look at how adding 3% of a fatty alcohol or fatty acid (like cetyl alcohol or stearic acid) could change the thickness of our lotion, and I'm sometimes surprised at how adding a titch of something can change a lotion so much! So I thought we'd take a look at how a small change can make a big difference. (For the purposes of this post, I'm considering 3% or lower as a small change.)

If we take a look at the water and cool down phases, there are all kinds of small changes we can make to our lotions to make a big difference! Consider humectants. I consider humectants essential to all lotions because they add extra moisturization very easily and they're generally pretty inexpensive. I've found a huge difference in lotions that don't contain a humectant - I live in a humid area, and adding up to 3% glycerin, honeyquat, sodium lactate or sodium PCA offers enough hygroscopic power to keep my skin feeling moisturized all day! You can combine humectants to offer more moisturizing power if you want. You could use 2.5% sodium lactate with 3% glycerin and 3% honeyquat (the latter in the cool down phase) for a very humectanty product.

Or consider hydrolyzed proteins. You can up to 2% of silk, soy, oat, or mixed proteins to your water phase to increase the film forming and moisturizing qualities of your product.

Or consider your extracts. We add these at up to 0.5% in the cool down phase, but they can offer a lot of anti-oxidizing, anti-inflammatory, and astringent qualities to our products! Consider salicylic acid (used at up to 2% in our products) or AHAs (used at up to 2%) and the benefits those two ingredients can offer in small quantities.

Think about ingredients like panthenol (used at 1% to 5%) or allantoin (used at up to 0.5%), which offer all kinds of great benefits to our skin, like increased wound healing and barrier protection. I like to use panthenol around 2% in the cool down phase, and allantoin at 0.5% in the heated water phase (although it can be used in the cool down phase - the key is to include before your mixture gets to 25˚C, which generally well after the cool down phase).

And consider things like fragrance or essential oils. At 0.5% to 1% in the cool down phase, they make a huge difference! Or preservatives. We don't need much, generally 0.5% to 1.5%, but they make a world of difference!

There are some ingredients I would never use in small amounts. Ingredients like aloe vera and hydrosols are best used at 10% and over, although looking at commercial products, you'd think 2% would be okay!

So if we take a look at the 62% water shea, soybean, and sesame seed oil recipe, we can do a lot of tweaking to get some interesting effects! And remember, every change you to make to the water phase or cool down phase should be removed from the water amount!

So let's add 0.5% allantoin, 2% hydrolyzed oat protein, and 2.5% sodium PCA to the water phase, and add 2% panthenol and 0.5% chamomile extract to this lotion recipe. This means we need to remove 7.5% from the water amount to compensate for our new additions (change in water amount noted in bold).

SIX INGREDIENT LOTION WITH SHEA, SOY BEAN, AND SESAME OIL (modified to include some small changes)
32% water
20% aloe vera
3% glycerin
0.5% allantoin
2% hydrolyzed oat protein
2.5% sodium PCA

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

2% panthenol
0.5% powdered chamomile extract
0.5% liquid Germall Plus
1% fragrance oil (Clementine Cupcake)

Weigh the heated water phase in a heatproof container and put into a double boiler. Weigh the heated oil phase in a heatproof container and put into a double boiler. Heat both phases until both reach 70˚C and hold for 20 minutes. Remove from heat and mix. When the lotion reaches about 45˚C, add the liquid Germall Plus, and fragrance and mix well. Bottle, and rejoice!

Join me tomorrow for making small changes to the oil phase!


Pam said...

Hi Susan,

I have been thinking a lot about tweaking recipes. If for no other reason I don't have a lot of the ingredients. At what point could you have too many humectants or extracts? The mfg may says use in the range of .05% and 2.5% but what if I want to use three extracts @ 2.5% (I am in love with extracts...don't tell my husband) would 7.5 would that be too much. I am also confused about fragrance. If I take 1% of 52 ounce batch I think that calculated to about 7 grams...OMG that was SO much fragrance...

Jillian said...

How big can the cool down phase be? Is there a general percentage point at which the emulsion would fail?

Nancy Liedel said...

I am loving this series! Thank you. I've got an issue though, I've been all over, looking for max amounts of several products that the supplier has not gifted me with. You said you found max use on there in your post on researching products. Can you tell me what I'm missing? It's usually right in my face. Thank you very much for everything.

Susan Barclay-Nichols said...

Quick comment, but I'll answer the other questions later (I'm in the middle of sewing a knit shirt and it's driving me insane!) You can find a ton of great information on usage rates here - the Cosmetics Info safe as used PDFs (which I've put on my server). There are some more links under cosmetic ingredients safety links on the right hand side of the blog (scroll down).

Susan Barclay-Nichols said...

Hi Pam. The amount you use of an extract depends upon the type of extract. For instance, you could add up to 1% rosemary and 1% green tea and 1% chamomile and all would be well (although they might end up precipitating at the bottom of your bottle in a toner because their solubility is about 0.5%). But if you combined 0.5% papaya and 0.5% another exfoliating extract, you'd be in for a world of pain and misery as your skin would feel quite raw. So it depends on the extract, its purpose, and its solubility.

There are very few extracts I'd use at 2.5%. White willow bark, maybe, but even so I think the most I've used is 1.5%. Come to think of it, there aren't any powdered extracts I'd use at 2.5%. Liquid - yes, like green tea or Multifruit BSC - but not powdered ones. Which ones are you using at that level?

If a 52 ounce batch is 1560 grams, you would add 15.6 grams of fragrance at 1%. It seems like a lot, but that's still 1% of your entire recipe. Why are you making such a huge batch of lotion? I rarely, if ever, go above 1000 grams or 30 ounces, except at Christmas!

Susan Barclay-Nichols said...

Hi Gillian. That's a great question, and one I've never seen asked or answered before. I've had some pretty huge cool down amounts - 15%, for instance - and still had stability in my lotions. I don't think there's a limit in the sense of how much can you add to the cool down phase anyway, but it is a great question! What were you thinking of using in the cool down phase or is the more of a curious question?

Jillian said...

Hi Susan,
I make a facial lotion for my teenage daughter's breakout prone, uber sensitive skin that includes 5% tea tree oil and 1% lavender extract, (to mitigate the tto smell,)and 2% cyclomethicone,and panthenol. It all has to go into the cool down phase and it seems like a lot. I sometimes have problems with the emulsion holding together and that is why I asked the above question.

I also have a fabulous face primer that is fabulously expensive that I thought I'd try to replicate. It has about 40 ingredients in it! Most of the useful ones are silicones with tons of questionable extracts.

Anyway, thank you for your response!

Susan Barclay-Nichols said...

Hi Gillian. If you're including 5% tea tree oil and 1% lavender essential oil, I would consider that an extra 6% and suggest you increase your emulsifier in the heated oil phase. Are you counting the cyclomethicone in the emulsifier amount as well?