Dear SurvivalBlog Editor:
I'm running out of storage room for my food storage. Would sugar or salt stored in mylar bags and food grade bucket with a gasket lid deteriorate if stored in a hot, humid environment, (such as garage)? Thank you for any advice you could offer. Take care, - Stephanie K.
JWR Replies: The beauty of salt and sugar is that they are "self-storing" and can have extremely long useful storage lives (potentially centuries) if they are protected from moisture. Just a bit of humid air and inadequate packaging will turn either of them into solid bricks, fairly quickly. If this occurs they can of course be broken up with hammer and chisel or dissolved with tap water, but that can be inconvenient and messy, particularly when you have the former granules stored in seven gallon super pails! Furthermore, without a good vapor seal, both sugar and salt can pick up undesirable odors, depending on where they are stored. Never store them near chlorine bottles, solvents, any petrochemicals, or any foods with strong aromas. (One exception is proximity to vanilla beans, but only if you want to have some vanillated sugar, for Liege waffles or other recipes.)
A food grade HDPE bucket with a good intact rubber seal should be sufficient for storing salt and sugar for just a few months.But a sealed mylar liner adds a layer of protection that is important for long term storage. Since HDPE is gas permeable over a long period of time, a mylar liner is recommended. (Mylar is 99% impermeable.) You can either buy mylar liners with zip-lock tops, or plain bags, and heat seal them. (The latter method takes a special tool that is fairly expensive.)
Similarly, honey has an extremely long shelf life. If it is stored in glass jars it should be protected from sunlight. When honey eventually (and inevitably) crystallizes, all that is needed is to apply low heat in a double boiler, to restore it to a palatable liquid form.
Storage temperatures encountered in a residential garage (as high as 120 degrees ) are generally not detrimental to sugar, salt, or honey. But again, moist air can be a big problem for sugar and salt.
A further consideration for salt is that if it is improperly stored in damp air, the salt vapor will induce rust on any nearby ferrous metals.