in this post, and I had to address it! (I'm editing a bit for length...definitely visit the post to see the conversation in full!) Hi Susan! I looked at my Crafter's Choice Grape Seed Oil I purchased from WSP about 2 months ago. It says on the bottle it is good for 1 year, until next spring. How is this possible? I asked a WSP representative about it...Cayla (the representative): I'm not sure where you heard three month shelf life... Here are our instructions. Short Term Storage: Air tight container. Dark location. Cool room temperature. Long Term Storage. Removing air from storage container will delay oxidation and rancidity (may need to place in a smaller container). Refrigeration can extend shelf life. Best Used By: One year from date of purchase.What do you make of this? I also have a bottle of Grape Seed Oil from the grocery store with a use by date of March 2014. The bottle says "Grape Seed Oil is an excellent source of Vitamin E (25% of the recommended daily intake) and contains antioxidants"
The short answer? Oils kept in a cool, dark place, the fridge, or the freezer will have a longer shelf life than one that is left in the bright sunlight in a warm place. So you could say that grapeseed oil kept under optimum conditions in which rancidity is retarded will have a longer life span than one kept in average conditions.
The long answer? They are technically correct - if you put most things in the fridge, you'll extend the shelf life - but there's no way you're going to get that kind of shelf life when grapeseed oil is used in our products! Your lotions, conditioners, balms, and whipped butters are going to be subjected to humid bathrooms, warm cars, and toasty purses. When your oil is subjected to the temperature of normal life, the rate of reaction will speed up, meaning there are more opportunities to have the oil go rancid.
I think this kind of claimed shelf life is disingenuous because it isn't going to have a shelf life of a year in our products. The shelf life listed really should be the average shelf life, not one under ideal conditions. I don't think grapeseed oil purchased today and kept in a cool, dark place will still be good by April 2013. We can't always detect rancidity - our oils are going rancid every single day, but it's only when it reaches a point where we can smell it that we call it rancid. Everything I've read says grapeseed oil has a shelf life of 3 to 6 months and that it doesn't contain a lot of Vitamin E, and I trust those scholarly resources more than I trust a supplier reading from a data sheet. (I will post some scholarly links over the next few days so you can look them up yourself!)
Don't get me wrong, I love my suppliers, but I've seen a lot of misinformation passed along from data sheets. I don't expect them to know everything, but I do expect the information provided to me should be accurate. When you find a great supplier, treat her like gold!
I love this question so much, we're going to do a few posts reviewing the topics of oils, shelf lives, rancidity, and retarding rancidity as part of our Chemistry Thursday series (although we won't wait until Thursday - I'll start tomorrow!)