Jar Warming

One of the biggest obstacles for me in learning to can was dedicating part of my stove to a giant pot of boiling water to heat my jars. Gallons of water seems so wasted to just heat up the jars before filling them. While it’s very important to preheat the jars before filling them with hot food to prevent breaking, I felt like this step was the worst chore ever. 

One of the main reasons for preboiling the jars is also to sterilize them, as any kind of contamination within the jar can make people very sick. If jars have been properly washed prior to use, this step can be skipped because any jar being processed (after filling) 10 minutes or longer in either a water bath or pressure canner is going to be sterilized. This was a huge breakthrough for me! I never wanted to see another giant pot of boiling water again.

In researching, I found that many use their dishwasher to not only wash their jars, but to preheat them as well for canning. This is an extremely useful tool because it keeps me from needing to wash 16 jars at a time, and preheat them. To do this, simply load your dishwasher racks with your jars (rings and lids don’t need to be put through this cycle) and start your dishwasher. Once they’re near the end of the drying stage they’re nice and hot and ready to use!

The problem with the dishwasher method is I don’t have a dishwasher, beyond my own hands, and many others don’t either. So I kept looking for another solution.

When I’m canning, I typically go through 8-16 jars at a time, sometimes more if making jam. Without a dishwasher to hold them all I’m left needing a lot of counter space for jars to dry after being washed. Enter the oven! With my large cookie sheet on the rack lowered to accommodate the jar height, I can fit at least 20 jars and no longer need to fill up my countertops.  

When I’m using my oven for jars I’m not talking about “baking” them at any high temperature. Your average temperature of boiling water is 212 degrees, so heating a jar to 350 is way beyond what is needed and could cause the jar to break from thermal shock. No one wants to lose a jar, so it’s key to keep the oven temp on a very low 200. Canning jars are made to withstand higher temperatures, but they’re not nearly as thick as Pyrex that is made for baking. 

Remember when removing jars from the oven to be safe, use oven mitts or a jar lifter, they’re hot! I remove one at a time to fill.

Safety first, and use your own judgment. This is not a method of sterilizing jars.