PREP vacuum sealing/oxygen absorber question...

[breezyhill]

quick question...

I'm using half-gallon mason jars for breakfast hot cereal storage, which I vaccum seal. the jars are full to the very top of the rim. is it necesary to leave room at the top for an oxygen absorber if I'm vac sealing the jar?

if it makes a difference, here are the ingredients, more or less, depending on what I've bought on sale or have on hand.

into my largest roasting pan I make a mixture of different things like oats, rye, wheat bran/oat bran, nuts, dried apples, raisins, kamut, cinammon, dried peaches, coconut. I mix it all up and then put into jars and seal.
thanks.
bh

 

[Tollwatch]

Depends on how much of a vacuum you are pulling on the jar.. if its 25" than no you do not.

The purpose of the oxygen absorber's is to remove the oxygen.. you have already done this when you evacuated the jar.

 

[bw]

It's not necessary to leave room at the top. If you're vacuum-sealing flour or something of that consistency, you need either a space or a paper filter (paper towel would do) to stop fly-up dust from getting in the seal, but that doesn't require space. If you're sealing grains or the like, you don't have fly-up dust.

Space at the top is a consideration only when wet canning - water bath or pressure canning. The contents bubble a little, and the space leaves room so the bubbling liquid won't get in the seal. Also, those canning methods don't leave air space between grains, so the space at the top is all the air there is.

Vacuum sealing does NOT remove all the oxygen, it removes only part of the air. There is oxygen remaining, and an oxy absorber will take that out of circulation. So oxy absorbers are still a good idea when vacuum sealing. Note that the absorber, by taking out oxygen, cranks the vacuum to a slightly higher level.

Also, consider diatomaceous earth whenever canning dry products.