Letter Re: Canning Jar Questions

Good evening, Hugh,

Your wife has posted a couple of articles indicating your family uses an industrial vacuum pump for vacuum sealing canning jars; do you have any recommendations on vacuum pumps for this task? How many inches of mercury do you regularly pull on canning jars? I’ve seen a couple of videos on Food Savers indicating they pull about 18 inches, but I suspect 20-21 inches should be more than adequate.

She also mentioned you made wood crates for storing and transporting canning jars. I’m getting ready to start making some; any suggestions? What dimensions do you use for the various size jars? – N.K.

HJL’s Comment: Most any laboratory diaphragm pump will pull the necessary vacuum. The point of the vacuum is to remove the oxygen from the jar. You can do this by throwing an oxygen absorber in the jar with the food or using your vacuum sealer to pull it out. (Warning: Do not try to store wet foods in this manner. Food poisoning is nothing to play with. If you don’t die, you will probably wish you were dead.) Since a hard vacuum isn’t a requirement for the storage, there are many brands of vacuum food storage pumps that can work. However, the Tilla Food Saver is the only electric consumer pump that I like. The others struggle to pull a vacuum as well. For those who don’t mind a bit of manual labor, the Pump-n-Seal is an excellent option (or backup unit) that will draw about as hard a vacuum as you can get without an oil type pump. We don’t use the intended method of sealing jars with this gadget, but instead connect the 1/4” vacuum line of the Tilla Food Saver lid sealer up to it.

We used a Tilla Food Saver until we wore it out, and that is when I made the built-in unit out of the laboratory diaphragm pump (purchased off of eBay). The laboratory units don’t like to be turned on and off rapidly, but they will run continuously. So we placed a valve in the line. Rather than turning the pump on or off, we control the access to the vacuum by turning the pump on when we begin and then vary the vacuum with the valve as we seal jars, turning the pump off when we are finished.

I built the boxes for the jars out of 3/8” plywood and 1/2 x 1 1/2 inch strips for reinforcement on the corners and edges, but this resulted in a heavy box. Next time, I will use 1/4” plywood and 1/2 x 1 inch strips for reinforcement. The boxes are simply made to fit 12 quart jars with a cardboard sheet between each jar. The quart box dimensions are approximately 15 1/4” x 11 1/2” x 8” on the inside.