I was recently told that flax seed goes rancid pretty much immediately after grinding. This took me a bit by surprise and also made me question my consistent advice to people to buy ground flax as we can’t obtain the nutritional benefits (i.e. healthy fats and both soluble and insoluble fibre) from whole flax seed. I did a little googling and the consensus is that ground flax will stay fresh for up to four months in an airtight container in either the fridge or the freezer.
Okay, so four months isn’t exactly instantaneous but, when you think about it that store-bought ground flax would have been stored in at least one warehouse before making its way to the grocery store shelf and then it would be sitting on the shelf for x amount of time before you bought it and brought it home. Provided it’s in a vacuum-sealed opaque package it will stay fresh for a couple of months but not knowing how long it’s been since it was processed, and not being one to use-up an entire package of ground flax immediately upon purchase, I’m not sure that I will be buying ground flax seed any longer.
Whole flax seed, on the other hand, will stay fresh for several years at room temperature. This means that my new and improved advice is to purchase whole flax seed and grind it yourself. You can use a food processor or a coffee grinder or one of those hi-tech blenders. Grind only as much as you need at a time or, if you grind extra, ensure that you store it in the fridge or freezer in an opaque, airtight container for no more than four months.