Question about vacuum sealing Mason jars...

Discussion in 'General Discussion' started by Ajax, Apr 13, 2011.

  1. Ajax

    Ajax Monkey++

    About a year or two ago I vacuum sealed some dry items in mason jars, like lintels for example and when I initially did it I used a seal a meal device made for jars like this and a break bleeder pump and go tthe jars up to 25 inHG of vacuum.

    I checked a few of the jars and it seems like it lost a little bit of the vacuum judging by how hard it was to take the lid off compared to a freshly vacuum sealed jar, one jar had popped back up but most of them were still depressed in.

    So what I am wondering is, is that common for mason jars to lose vacuum? Canning seems to keep them sealed so is it as simple at slightly heating the lids in the oven to soften the seal and then vacuum seal it while it is still warm? I noticed the lid wasn't real tight so I revacuum sealed it and tightened it down more although I don't know if the tightness of the lid would matter or not. Or maybe just buy new lids and redo them.

    Like I said I am only going by how tight the lid was due to the vacuum compared to a newly sealed jar and I would say it was about half as hard to get off.

    I don't have a lot in mason jars but I want to make sure I get this squared away before I put more in jars.

  2. kckndrgn

    kckndrgn Monkey+++ Moderator Emeritus Founding Member

    hmm, first thoughts. Were the lids new or previously used? After adding the dry goods was the rim of the jar cleaned to remove any dust that may have been left behind.
  3. Ajax

    Ajax Monkey++

    They were new lids and I think the lid seal and jar were clean, I didn't pack any powdered goods just some dehydrated veggies and lintels.
  4. kckndrgn

    kckndrgn Monkey+++ Moderator Emeritus Founding Member

    Lintels can be "dusty", same as dehydrated veggies. Enough of that "dust" gets on the rim of the jar and you can't get a good seal.
    Next time use a damp, clean towel and wipe the rim of the jar off before putting on the lid.
    One other thing, I think (don't know for sure) that the lids will require some heat to form an effective seal. If you think about canning, usually the jars are hot (at least warmed) you add hot ingredients, and either pressure can or put in a boiling water bath. All just a guess on my part, but the heat may make the seal on the lid conform to the rim of the jar, thus creating an air tight seal.
    Witch Doctor 01 likes this.
  5. Ajax

    Ajax Monkey++

    I think I'll take the lids back off and wipe them down and then reseal.

    Does anyone else know about heating up the seals to get them to work better?

  6. chelloveck

    chelloveck Diabolus Causidicus

    I think it's the jar you need to heat rather than the seal. As the jar cools down it will draw the lid and seal down onto the rim of the jar, creating a lower pressure atmosphere in the jar than the atmosphere outside of it. If my highschool science is right, the outside atmosphere is actually pushing down on the jar lid.
  7. Ajax

    Ajax Monkey++

    I have a seal a meal mason jar sealer with a vacuum hand pump that will vacuum seal it. I wonder if heat like that woudl work for dry goods, if so it would be a good way to vacuum seal in a pinch.
  8. fedorthedog

    fedorthedog Monkey+++

    if the jar is in the sun the interior temp goes up causing pressure inside the vessel to rise this would negate the vacuum. Once the pressure equals the outside air pressure the seal is gone. This would be true of any storage location where jar temperature can exceed air temp.
  9. Ajax

    Ajax Monkey++

    They are all stored in wood cabinets with no openings so the sun doesn't hit them at least.
  10. Ganado

    Ganado Monkey+++

    I was discussing buying a FoodSaver so I could seal my mason jars for seed storage and some other things. After tossing some idea's around one of my biker buddies suggested I get the Food saver Jar savers FoodSaver T03-0006-02P Regular-Mouth Jar Sealer and Wide-Mouth Jar Sealer Bundle: Kitchen & Dining
    THen use a brake bleeder vacuum pump instead of the food saver(gotta love practical mechanical guys ) :D HFS (TM) 2 in 1 Brake Bleeder & Vacuum Pump Test Tuner Tool Kit New: Automotive
    My question then is... how much pressure should it be pumped too?

    Any suggestions?
  11. kellory

    kellory An unemployed Jester, is nobody's fool. Banned

    Well, that bleeder kit has a maximum of 30lbs, so you can't pull more than that. Those are designed to pull a liquid through a tube, where it will almost flow on it's own. Don't expect long life out of it, as it is not meant for that purpose.
    Ganado likes this.
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