choosing our surfactants - in this post. We took a look at how to make our product rinse off more cleanly in this post. I touched a little bit on pH in surfactant based products in this post. So it feels like time to create the basics of our base before looking at increasing mildness and adding exfoliants!
What do we need in a surfactant based scrub? We need surfactants, water, preservative, scrubbies. Yes, it really is that basic!
For the dry skin version, I think I'll work with SMC/SMO taurate and cocamidopropyl betaine. (Although the polyglucose/lactylate blend would be awesome for someone with really dry skin!)
For the oily skin version, I think I'll work with DLS mild and cocamidopropyl betaine.
For the normal skin version, I think I'll work with ACI and cocamidopropyl betaine.
Why cocamidopropyl betaine? Because reduces irritation (increases mildness), offers good flash foam, and can behave as a humectant. It thickens our products and it is a gentle detergent. It is generally used as a secondary surfactant, meaning it isn't great on its own but works to make the other surfactants more awesome. You could use it on its own, but it is really really gentle and might not cleanse as much as you would like for even the most delicate or sensitive skin.
How much of each surfactant should we use? I generally go for 40% surfactants in my product...and what I mean is that I put something like 25% DLS mild and 15% cocamidopropyl betaine, which gives me 40% of those ingredients. But am I really getting 40% surfactants?
Why 40% surfactants? When I read through various cosmetic chemistry books I own and searched through countless recipes, it seemed to me that 40% was a good level that would offer good cleansing but not too much detergency. It meant I could use a lot less of product x than I had been using from store bought products - they might be as low as 10% - and I never made a product that had been irritating to my skin on paper or in the shower! As you'll see in the next section, I'm not really using 40% surfactant but a percentage of that amount. You are free to use other levels...
My cocamidopropyl betaine is 30% active ingredients, meaning that using 15% cocamidopropyl betaine in my product will give me 4.5% active cocamidopropyl betaine. My DLS mild is 32% active, so using 20% in my product will give me 6.4% active disodium laureth sulfosuccinate. My total is 10.9% active surfactant, which is a lot lower than it seems in our original recipe!
How did I figure this out? Uncomfortable about math? If you'd like to learn more about percentages and such, click here to see the Frequently Asked Questions section and scroll down to calculations!
You can find the safe as used table from the Cosmetics Ingredient Review here. Do a search through the document to find your ingredient.
Why do we use water at all? Isn't it just a waste of space in the bottle? No. Every ingredient has a safe as used amount, and we can look to see that cocamidopropyl betaine starts to get irritating at levels of 35% or so (although I can't find anything for DLS mild except the comment that it is "gentle even up to higher concentrations"). If we used 90% surfactants - assuming we are using 10% something else like glycerin or preservatives - we would exceed those safe as used rates quite easily and cause irritation. As well, we don't want something really foamy for our face, and 90% surfactants would be like a bubble bath in the sink every morning...and we want stuff that will rinse off easily to prevent that tight and dry feeling after cleansing! Finally, it saves us money. Distilled water costs maybe $2.00 for a gallon or 4 litres, which is way cheaper than a surfactant that might be upwards of $20 a litre!
Should we use just water in our recipe? In this base recipe, I will be using all water, but I really do recommend you alter it to include wonderful things like hydrosols, extracts, humectants, and everything else that is water soluble in the product. We will be making all kinds of alterations to the product once we get the base recipe finished, but I really like to keep it simple when I'm creating a recipe template because the more things we add, the harder it is to see what is causing problems or being awesome when we make it for first time!
How much water to use? Whatever isn't being used by the surfactant and the preservative is the water amount. As I've mentioned before in lotion making recipes, the water amount can be played with - reduced, replaced, or increased - so it becomes "water q.s", which means to add water so the recipe equals 100%. We'll figure out the water amount when we've done the other things.
A thought about using tap water: Please don't. You can boil it and do other things to it, but if you have metals in your water they can mess up the preservation and other ingredients (click here for more information on metals and oils) You can use a chelating ingredient like EDTA or citric acid to bind those metals so they can't wreak havoc on our products, but it really is easier to get distilled water or reverse osmosis water or another water that doesn't contain those metals rather than spending money on chelating ingredients! I like chelating ingredients and use them, but I start with distilled water every time. And yes, you should heat and hold distilled water because the heating and holding process isn't just about killing bacteria, it's about getting your ingredients to the right temperature and same temperature if you have two phases.
If you've read more than a few posts on this blog, you will know that preservatives are not optional when you are making water containing products. Choose one that works well within your budget and philosophy, but use one. I generally use Liquid Germall Plus at up to 0.5% in my products, but if I'm planning to use a lot of botanical ingredients - and I do like to do that with my facial products - I might consider using Germaben II at up to 1% in the cool down phase. Click on the preservatives link to see all the posts on that topic and the chart.
If you aren't completely sure about what you're planning to do with this recipe, hold off on choosing a preservative until you see what things you might add that could conflict with your choice. For instance, Tinosan can't be used in a clear container and can't be used with cationic ingredients, while Advanced Aloe Leucidal doesn't like anonic or negatively charged ingredients, so it won't play well with any facial cleansers containing anionic surfactants.
We've gone over the physical exfoliants (part one and part two) and chemical exfoliants we could use in other posts, and since this is already getting pretty long, I'll direct you over there for more information. If I'm going to use something like AHA, I need to ensure I am adding it at the correct safe usage level and in the correct phase. For AHA, it's generally up to 10% in the heated water phase. I would start with a simple recipe and a lower amount to see how my skin can tolerate it. In our sample recipe, we'll be using 5%.
If I'm using physical exfoliants, I tend to create my recipe, then add the scrubby amount afterward as it can be a game of measuring, weighing, and adding more each time depending upon the time of year and sensitivity of my skin. Choose an exfoliant that plays well with your facial skin - so pumice is right out - and doesn't get soggy in water - some seeds, loofah, and shells might not be the best choice here.
A side note...Substitute the surfactant of your choice for the DLS mild in this recipe. Remember that surfactants that are outside the pH range of 5.5 to 6.5 - like decyl glucoside or disodium cocoamphodiacetate might have to be altered with the inclusion of 0.2% citric acid or another acidic ingredient. AHAs will work well for this! And remember to take a look at the active part of your surfactant. This recipe as written has about 11% surfactant concentration, whereas adding 25% of polyglucose/lactylate blend with its 54% to 59% active concentration means you have 14.75% of that surfactant alone, leading to a total of 19% active surfactants. Not a big deal, but if you have sensitive skin or really dry skin, you might be getting too much surfactant. Just remove some of the surfactant and increase the water by that amount.
SAMPLE BASE FOR A FACIAL CLEANSER FOR OILY SKIN WITH PHYSICAL EXFOLIANTS
HEATED WATER PHASE
25% DLS mild
15% cocamidopropyl betaine
59.5% distilled water
COOL DOWN PHASE
0.5% liquid Germall Plus
Weigh the heated water phase in a heatproof container so you can place it in the double boiler. Before putting in the double boiler, please record the weight of all the ingredients and the container as you'll want to replace the evaporated water when you remove it from the double boiler. (Click for more details on evaporation.)
Heat until the ingredients reach 70˚C or 158˚C and hold for 20 minutes. Stir while you're waiting to ensure all the ingredients are well incorporated. Remove the container from the double boiler, weigh, add hot distilled water to reach the original weight, then stir and allow to cool until it reaches 45˚C or the temperature suggested by your preservative. Allow to cool. Then add your physical exfoliants.
Remove 100 grams of this product and put into another container. Add 5% of your chosen physical exfoliant to the product and stir. Try. Not scrubby enough? Add another 5% and stir. Continue until you're happy with the exfoliation level. Keep really good notes, and make sure you choose a container that can handle all that extra stuff - a jar is always good whereas a foamer bottle is a terrible idea!
If you simply can't wait until tomorrow, you can remove 5% of the water and include 5% AHA in the heated water phase, but you will have a very thin product.
As much as I think this sample recipe will offer some nice gentle cleansing, there are so many other things we could add to a facial cleanser to give it some serious oomph! At the very least, we should consider adding some thickeners to the product and some mildness enhancers. What about some nice water soluble oils for moisturizing and extracts for their anti-oxidizing properties? Join me tomorrow as we work a little more on this base recipe!