Wednesday, October 21, 2009

Determining shelf life of your lotion...

Caroline posed an interesting question...My question is if I use a certain percentage of presevative how long will my product last? How long will it be protected? Is there a timeline?

Great question! How do we figure out how long something will last?

Preservatives and anti-oxidants are only one part of the equation. We need to check the shelf life of each ingredient in our lotions.

BASIC LOTION RECIPE (originally from this post)
70% water
15% oil (sunflower, soy bean, rice bran, or olive oil)
5% shea or mango butter
3% cetyl alcohol
5% emulsifier (BTMS or Polawax)
1% fragrance or essential oil
0.5% to 1% preservative

OILS: If I'm using the suggested oils above, I would probably have a shelf life of about 9 to 12 months. (I use high oleic sunflower oil for a longer shelf life). If I add some anti-oxidants or chelating ingredients, I could probably stretch that a little longer, but I like to think of it as guaranteeing the shelf life of a year.

The shelf life of your oils is only as long as the shortest shelf life of all the oils. If I added hemp seed to this mixture, I would reduce the shelf life to 3 months. If I added grape seed oil to this mix, then I'm going to reduce it to 3 to 6 months (and I'd side with 3 months). If I used squalane, fractionated coconut oil, and shea oil, my shelf life is going to be more than a year without the anti-oxidants.

BUTTER: Shea or mango are very long lasting butters - up to 2 years - because they are mostly saturated (very few double bonds). So they are more resistant to oxidation than our unsaturated oils. Again, anti-oxidants will extend the shelf life.

FATTY ALCOHOL: I've seen cetyl alcohol as having a shelf life of up to 2 years (I've also seen a shelf life of one year, so check with your supplier).

EMULSIFYING WAX: Check your emulsifying wax for the shelf life - each one is different. Polawax has a 2 year life span. When emulsifying waxes go bad, they start creaming. So it's important to know how long you've had your most important ingredient in a lotion!

FRAGRANCE OR ESSENTIAL OIL: With fragrance oils, you should have a good idea how long each one will last - if they go off, they are going to add stench instead of loveliness to your products! With essential oils, you need to know the shelf life and what happens when the oil goes rancid. Sometimes essential oils can be harmful when they oxidize!

WATER: Can't forget the water. If you're using tap water and not using a chelating agent, your lotion will oxidize much quicker than one using distilled water and good manufacturing processes.

PRESERVATIVE: Your choice of preservative can also determine the shelf life. I use Liquid Germall Plus for most of my creations (Phenonip for creations without water like sugar scrubs or shampoo bars.) LGP has a shelf life of two years, so the most I can get out of a lotion using this preservative is two years.

CONTAINERS: Yep, consider your container. If you have a brand new one from your supplier that has been kept in a good location, your container should be considered clean. If you're re-using a container or have stored it in the equivalent of my bedroom (which is incredibly messy and dusty and untidy), that could contaminate your lotion! (Please don't re-use containers. I know we're all about the recycling and re-using, but it's just not a good idea. If you've ever made a sugar scrub, then left the container out for a few months after using it all up, you'll know the smell of rancidity. It's horrible. And a pre-used container could have all kinds of things in it that can ruin a beautiful, long shelf lived lotion!)

Ingredients like extracts and botanicals can reduce the shelf life of your product dramatically, and need to be well preserved. Before adding any ingredient, know the shelf life and how it can affect your end product. And if there's something you simply must have - let's say aloe vera - but it will reduce the life of your lotion, consider using it in another format with a longer shelf life - like aloe butter or aloe oil. And if you must have it and can't compromise, then make sure you note that on the product label. Hempseed oil is amazingly lovely for acne prone skin like mine, so I put the date I made the product and the throw away date in big black letters on my labels so I won't be inclined to keep it longer (because rancid oils really aren't going to help my skin!).

And remember, the shelf life starts when you get the ingredient, not when you use it. If you've had that olive oil for 6 months, you've got 6 months left...in theory. If you've put your oils in a warm, well lighted area, photo-oxidation can speed up the process of rancidity and leave you with a shorter shelf life. This is why freezing or keeping your oils in a fridge is a good idea! (And, I hate to say it, you have no idea how long the ingredients have been on your supplier's shelves, so we need to take that into account!)

Always date your ingredients when you get them and adding Vitamin E to your oils when you receive them can extend the shelf life! Here's a little information on how to much to add (original found in the comments section of the recent anti-oxidant post.)

Something like Covi Ox T 50 has 50% tocopherol, which means 1 gram contains 0.5 grams tocopherol. For this product, it's recommended at 100 to 400 ppm (or 0.01 to 0.04%) for unsaturated oils, so you'd want to add 0.1 to 0.4 grams per kilogram. It's recommended at up to 2000 ppm (or 0.2%) for polyunsaturated oils (something with a really short shelf life, like hemp seed oil) so you'd want to add 2 grams per kilogram.

So how long would I give my lotion above? If all my ingredients were brand new, if I followed good manufacturing processes (heating and holding, and so on), if I use my preservative, anti-oxidants, and chelating ingredients, I'd say a year. But I'd tell anyone to whom I gave the lotion 6 to 9 months to be on the safe side. If my ingredients weren't brand new - which they likely aren't! - I'd consider the shortest shelf life of the oils and subtract the time I've had it.

I've just stocked upon my oils again, so the date on them would be October 1, 2009 (or so). When I make products to give away at Christmas, I will use a date of 6 months to account for the time since I bought it, plus a little extra to be safe.

Please note...all these comments are about making products, not selling them. If you are selling your products, please get them tested prior to even thinking about selling them and always use batch numbers so you can track what you've made. I don't sell products, so this blog isn't geared towards the business side of things...

And this also applies to any products you make. If your ingredient has a shelf life (and all ingredients do, even if they're long ones!) then make sure you know what it is!

Great question, Caroline! Thanks for making me think so early in the morning! (That was not said sarcastically - I do all my best thinking in the morning after three pots of tea!)

11 comments:

Caroline said...

Thank you so much for this post, this is just what I needed to know.

Just Dej said...

Thank you so much for this for this post Susan! I am in the beginning stages of creating a leave-in for my daughter's very dry hair and wanted to be as safe as possible. I do have a question thought. When you say that emulsifiers start to cream, do you mean they become softer and take on a more buttery viscosity? I have some bulk BTMS from 3 years ago that I was considering trashing, but it does not have any of the properties I described above.

Susan Barclay-Nichols said...

Hi Just Dej. They will start to cream in the lotion, not sitting in a bag in our workshops! (Click here for the post on when lotions go wrong!). Creaming refers to a type of emulsion failure, so you'd have to use your emulsifier in a lotion before you'd see this problem.

I wouldn't use something that was three years old - we know that BTMS-50 has a shelf life of two years, so three years is just asking for a rancid product! And BTMS doesn't smell nice when it's rancid! I don't know if you're able to smell the fishiness in it - when it's gone off, everyone can smell the fishiness. Not nice in our hair!

I just wrote an updated version of this post here - , Question: How do you figure out shelf life? It doesn't address your question, but it gives you some information on how to determine how long that product will last!

Lee Ann said...

Hello, I am very new to formulating and have purchased quite a few ingredients and have read the suppliers instructions regarding the ingredients but I still have a very basic question. As long as the storage instructions do NOT indicate that the item should not be refrigerated or frozen, can I put the dry ingredients in a foil zip lock bag and the oils in amber glass (if not already in amber glass) and store in the refrigerator?

Susan Barclay-Nichols said...

Hi Lee Ann. I haven't found an ingredient that I couldn't store in the fridge, so I feel very comfortable in saying yes, you can put them in the fridge. Better yet, you can store some in the freezer. Oils, fragrance oils, essential oils - these can go into the freezer easily, although I wouldn't store glass in there as it could get broken. Put them into a plastic bottle for freezing.

Caleb said...

Hi Susan,
My wife and I are starting to make homemades goods together, we have a goat and are really wanting to use the milk in our lotions. We wanted to give them as Christmas gifts this year but I had a few questions. Number one, is there much of a benefit to using goat milk as opposed to just water? And number two what would the shelf life on something like that be? The current recipe we have is: 10.2 oz of distilled water, 10.2 oz of goat milk, 1.2 oz of emulsifying wax, 3.7 oz of avocado oil, 1.2 oz of shea butter and .3 oz of phenonip. Any help or suggestions would be greatly appreaciated!

Caleb said...

Im sorry i need to correct myself. The recipe we're using is: 16.2 oz distilled water, 1.8 ox of goat milk, 1.2 oz of shea butter, 1.7 oz sweet almond oil, 1 oz avocado oil, 1.2 oz emulsifying wax, 1 oz of stearic acid, .2 oz of phenonip. Sorry about that and I hope im not asking too much. Thanks again!

Susan Barclay-Nichols said...

Hi Caleb! Could you please put your recipe in percentages as it's hard to figure how the proper amount of things using ounces. As an aside, if you've never made anything before, you'll want to start with a lotion that is easy to preserve. Adding milk of any sort will make that a challenge. And, to be honest, I've never found anything about goat milk offering benefits to our skin.

Susan Barclay-Nichols said...

If you have any links to good sources about goat milk and skin, I'd love to read them!

Caleb said...

I can't find the original article but I have a note that said it originally came from Soapqueen.com . It roughly breaks down to: 66% distilled water, 7% goat milk, 5% shea butter, 7% sweet almond oil, 4% avocado oil, 5% emulsifying wax, 4% stearic acid and .82% phenonip.The recipe basically said we could take 10% of the distilled water and substitute goat milk. But I really don't want to have to keep it in my refrigerator until Christmas haha. I've read that I could combine preservatives to make it last longer, but if there are no benefits to it I really dont want to add the extra cost and chemicals. Thanks again!

emilykathrine said...

Hi Susan,
Love your blog, you're my go-to resources for skin-care products. I find you are particularly helpful with the preservative issue, so many recipes and websites on the internet ignore this issue! I've used phenonip before, with success, and am planning on making a large batch of0 scrub for friends and family for christmas. However my bottle of Phenoip says it expires in April 2017. Does this mean any product I was to make with this bottle would expire in April 2017? I can't find much (if any) discussion of the expiration of preservatives themselves on the internet.
Any advice would be much appreciated!
Cheers,
Emily