I can't say "necessary" but I routinely use them when stored in jars. I don't when I vacuum seal them. One of those "can't hurt, might help" situations.

I imagine it would make more of a difference if the foods were not

fully dried or if you wanted really long term storage.

Dave

Thanks. I'm new to dehydrating, and I've never heard of these. I do have one of those food saver jar sealers. But I agree if it doesn't hurt & it might help, I should try some. Now I just need to find some...

dave, i assume you use them in canning jars. do you warm the lids ( dry, not wet)? do you keep the rings screwed on tight? i have some and wanted to store white rice in them (better price on big bags). but the O2 absorbers don't create a good vacuum. i wondered if the lids would seal without heat and vacuum from a BWB. what's your method, and long term results? thanks !

I never worry about creating a vacuum for dry storage items. I know some do it with either a jar vacuum sealer or with the oven methods (which isn't recommended) but I am in and out of the jars too often to worry about it re-doing the seal. I use some old 1/2 gallon jars as well as some quart jars for my dehydrated foods storage and just screw a lid and ring on normal tension.

Now this is for fully dried foods of course. If dealing with only partially dried things like tomatoes, they go into the freezer in vacuum seal bags.

Dave

What size oxygen obsorber would you use if you were putting up tomato powder in a pint or quart mason jar that is not vacuum sealed. I have been looking on Amazon but there are too many sizes (CC) and I can't figure out which one to order. 50cc - 100cc -250cc ?????