Sealing mason jars in a chamber vacuum sealer

So I had an epiphany! I'm really into this sealing stuff in a jar thing using the mason jar sealing attachment on my Tilia FoodSaver:

This is great for squishable stuff like lettuce and is also nice because the jars and lids are more easily reusable than the plastic bags.

The problem is that it's not nearly as easy as it looks to use the attachment. Probably a good half of the times I try to seal it fails to take and I have to let the FoodSaver rest a bit and then try again. And it doesn't work with wide mouth jars.

I would certainly put up with this if not for the much more impressive ARY VacMaster VP210 in my kitchen.

It should have occurred to me much sooner, but there's really no reason why you can't put mason jars in a chamber vacuum sealer! This works because the pressure in the chamber drops and since the lid is loose, the pressure in the jar drops too. Then, when the pressure in the chamber is brought back to room pressure the pressure in the chamber is greater than the pressure in the jar and the lid makes a seal. Excellent!

The VacMaster doesn't successfully seal 100 % of the time, either, but it's capable of running more or less continuously, and I can put a half dozen jars in at a time, so it's not such a big deal. And the vacuum is so strong at 30 seconds that I can barely get the lids off!

The big jars are rarely a problem, but the 4 oz. mini-jars gave me a lot of trouble… until I realized that the best way to seal dry things (like salad vegetables) is to put the jar in the sealer upside down! The weight of the jar keeps the lid from flopping around as the air is rushing into the machine when it's re-pressurizing and breaking the seal.

Update:I've found this technique for opening vacuum sealed jars to work very well.

Update7/7/2010: If you're sealing dry-ish things like lettuce or salad vegetables, it works even better to put the jars in upside down. This causes the weight of the jar to help seal the jar. This is especially useful with 4 oz. jars which are particularly obstinate.

I realize that few of you have a FoodSaver and even fewer have a  chamber vacuum sealer, but this is so cool I had to share. And someday, someone will find this post via Google and I will become the world's foremost expert on vacuum sealing mason jars in a chamber vacuum sealer.

Update6/12/2013: Especially with the small-mouth 8 and 16 oz. jars, putting the screw-on right fairly tight works the best. You'll get a great vacuum seal and then you can remove the ring. Logically I thought loose would work better, but really tight works best.