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Question about shelf life of raw materials
The question of shelf
life bothers me as often as I go through my ingredients. I know that the best
approach is to reach out to the supplier and get a technical data sheet. But, I
am a hobbyist. It means that I get my ingredients from repackers such as Lotion
Crafter, Makingcosmetics and such.The fact that formulating
is my obsession doesn’t help. I currently have close to 200 ingredients (not
including pigments) which I proudly collected from all over the globe. I buy small
amounts but they still expire. I must make a caveat when it comes to
preservatives, I only get them from the US and one reliable place in Italy, I store
them in the fridge I obtain all technical data.But what about other
ingredients? May I please ask you to share your general knowledge on what to consider
when it comes to shelf lives?For example:
Powders have longer shelf
life than liquids (which I assume means that I should rather get 99% glycolic
acid rather than 70% and 100% sodium lactate rather than 60%)Synthetic ingredients often
have a longer life than plant extractsSaturated fats live
longer than polyunsaturated (I don’t use a lot of triglyceride based oils but I
lookup molecular structure to check for double carbon bonds)Double bonds in the benzene
ring are relatively stable (alkyl benzoate)Anticipating professional
forum members saying that those all are gross generalisations, I want to
encourage my fellow hobbyist to remember that there is no one size fits all and
it’s better to ask a supplier. But general rules would be great to know.Thank you!
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5 Replies
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A less general question on the topic. Why cetiol ultimate (undecane, tridecane) which is a hydrocarbon has a short shelf life?
Is there a way to know how stable is a hydrocarbon (like double bonds for plant oils)?
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hi there
Well, it is somehow difficult. Normally if a supplier Writes down an Exp date for an ingredient and you are not an expert or have the possibility to retest the product you should not use it any longer.
In general, if you can confirm that the Specification of the Raw material still fits ( means no Colore change / Smell / Microbes / Density / Refraction whatever the Specification gives you) you can use it for another 3 months.
Practical Approach:
For oils, I would say you notice if they are still ok or not if they smell ransom they have gone and you need to get new ones. Of course, you need to take into consideration that your product’s long time stability will be more challenged with an older oil.
For Tensieds Concentration of the Tensied is not as important yes a non-Water Product is more stable than a water one but most are self-preserving so normally no problem there if the coloration does not change.
The only real issue in my opinion is emulsifiers. you do not see if they are still ok or not but the Formulation may not be stable if they are too old so if you can not confirm the Specifications of them throw them away.
For Cetiol Ultimate it can start to smell if not stored correctly ( gets a sour smell). I guess its because of the very small chain length
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@Gordof, thank you very much!
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I’m also interested in this, specifically how long tightly sealed powders can last. I do keep color-changing desiccant (silica gel) in each container, so I at least have some indication of relative humidity.
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Be aware suspensions/solutions may not be stable in refrigeration - solutes may fall out of solution at reduced temperature.
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