Saturday, September 3, 2011

Question: Adding preservatives to anhydrous products

In this post about making whipped avocado butter, Katie writes: I am just wondering why you did not use a preservative in this product? I just made a whipped shea butter for the first time using sweet almond butter, shea, vitamin e, and essential oils. It sounds like its consistency is similar to yours and it too is a little greasy at first but soaks in nicely. Loving your blog! I was considering doing lotions but am honestly afraid now of all of the bacteria and such that can grow on it. 

I also read that you do not consider there to be any natural preservative. Your post was from a little while ago, so maybe you have changed your thoughts on this? 

Love that you're from the lower mainland. I am a Langley girl living in Vancouver right now. 

Hi Katie! If you're looking for supplies local to us, look to the right and down for the supply list. We're so fortunate to have so many great suppliers within driving distance! I'm familiar with them all and they are simply awesome suppliers and people! (I'm off to Langley this morning and had hoped to do a little shopping, but Voyageur is closed for the long weekend. I'm glad they give their employees that time, but I need some cocamidopropyl betaine!)

Here's the recipe for that whipped avocado butter above...
77% green avocado butter
22% rice bran oil
1% fragrance oil (Clementine Cupcake, what else?)

We don't need to use preservatives in anhydrous products, that is to say products that don't contain water, because water is the big bad worry when making bath and body products. (Click here for more information on water and contamination.) We can use an anti-oxidant like Vitamin E (0.25% to 1%) to retard the rancidity of the oils and butters, if we wish, but we don't need to use a preservative if we're making an oil soluble product. (I didn't use an anti-oxidant because this should have a 1 year life span, and I only made a bit of it!)

Why, then, do I need to add preservatives to scrubs? Because a scrub will be exposed to water - you'll dip your hand in during a bath or shower and oops, there's some water - and when we add water to any product, we run the risk of contamination! I know, I know, you'll be very careful and dry your hands carefully before using, but there's always that little bead of water that can run down your arm into the container that might be enough to sit on top of the scrub and cause problems! (Click here for a discussion about water activity and sugar scrubs!)

I'm so glad that you're worried about preserving your lotions - that awareness will ensure you will make wonderful products! If you heat and hold, use good manufacturing processes, and choose a broad spectrum preservative that you use at the suggested usage rates, you should be able to make an awesome lotion that is well preserved and safe. In all my years of lotion making, I have never had a lotion show any visible contamination, even in my early days when I was a lot more impatient and didn't follow the rules as well as I should have! (The words "visible contamination" are vital in that sentence because I don't have access to testing for non-visible contamination!)

I had a container of foot lotion I kept by the side of my bed for a few years. I put it in a wide mouth Mason jar and abused it like silly for science! I stuck my fingers into it when I hadn't washed my hands, I put a spoon into it after I'd licked it, I left the top off for days, and so on and it never ever showed any signs of microbial growth. I threw it away when it started to smell rancid, and I was surprised that it made it so long with olive oil, soy bean oil, and mango butter (normally about a year). The power of anti-oxidants compels make an awesome lotion that doesn't go rancid immediately! 

As for the question about natural preservatives...can I answer that one tomorrow? There's so much to write about preservatives and I really want to post this today, so join me tomorrow for that topic!

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