*Slowly* opening vacuumed mason jar?

[joniverson]

I have been using a vacuumed mason jar for a special project. Now the time has come to release vacuum in order to access internal contents, but the vacuum must be released slowly. Most jars are opened this way by placing a knife or similar object under the lid's edge under air quickly rushes in and the lid is released, but is there some way to remove the lid slowly? Thank you!

 

[kuruman]

How did you evacuate the jar to begin with? Can you reverse the process?

 

[dlgoff]

... is there some way to remove the lid slowly?

I'm assuming this is from your freeze drying project. So how did you end up getting the vacuum, as you never said how you ended up doing the lid.

 

[joniverson]

Kuruman: I used one of https://www.foodsaver.com/accessories-and-parts/jar-and-bottle-sealers/foodsaver-wide-mouth-jar-sealer/T03-0023-01P.html and single stage pump to evacuate the jar. Unfortunately, the vacuum lid adapter seems to seal almost immediately when vacuum is reversed and I don't see any way of releasing slowly.

digoff: Yes, this is actually a part of the project, another experiment. What I originally ended up doing was fitting #13 rubber stoppers to the jars (interestingly, I found out that there is a difference between the black #13 rubber stoppers and #13 tan... the tan ones end up getting sucked into the jar after a week or so, plus they are physically smaller than #13 black). The stoppers were center drilled and fitted with 1/4" pipe and plumbing valves. This has worked out well, but between the cost for these large stoppers, pipe pieces, and valves, it's expensive. The mason jars with their native lids evacuate and hold well up to 29" Hg and I was just looking for a simple way to release the vacuum slowly after a time. This would be cheap and easy to repeat. Right now, I have take a rather large cookie type jar and epoxied a valve into the lid. It's larger than the mason jar, so the mason will fit inside. Evacuate the larger jar until the mason lid releases, tilt the assembly so the mason lid falls away, then slowly release. I'm not sure this will work however. I have been able to somewhat more slowly release mason jar vacuum with careful strategic pressure applied from whatever opener I am using, but I'm not sure how repeatable and consistent this is.

 

[ChemAir]

Evacuate the larger jar until the mason lid releases, tilt the assembly so the mason lid falls away, then slowly release. I'm not sure this will work however.

Could you hang a magnet from the top lid, so that when the pressure equalizes, the (inner) lid just sticks to the magnet? You could then re-pressurize in whatever controlled fashion you want.

 

[Rive]

If the lid's edge allows it then you might be able to use a needle (for syringe) instead of knife through the rubber.
A drawback that you will harm the rubber. Also, you still have to find a way to control the air flow, but at least you will have a way inside.

 

[joniverson]

Ok, I have since abandoned this method since my new desiccator vacuum jar arrived, but I am having trouble, and I have added the info to my original thread. I hope someone can help.