Pressure canning in oil

Asked September 10, 2018, 5:21 PM EDT

I am new to canning, though my wife has been doing it for years. I raised some Italian pepperoncini (AKA Calabrian peppers) from seed this year with the intention of canning them in oil, the way they are sold commercially. About the time the first group ripened, I started looking for recipes and discovered that water bath canning in oil is not a good idea, and used a recipe that used a little oil and a lot of vinegar. In looking for recipes I learned that most vegetables need a lot of acid to be canned. That's when I discovered pressure canners, one of which I immediately purchased. Still, I couldn't find recipes and times for canning in oil, even with a pressure canner. As nearly as I can tell, the reason is that fat is an insulator and there's a concern that the Botulism spores won't reach 240 degrees in oil. I partly understand that concern with excessive animal fat, but can't imagine that vegetable oil is nearly the insulator animal fat is. It seems logical to me that if I use hot oil instead of hot water to pour into the jars, then use a slightly higher pressure and leave them in for a longer time, that the heat would penetrate sufficiently to kill the spores. But I'm not interested in taking any chances with illness based on just my logic. So, my question is, can hot peppers be safely pressure-canned in canola and sunflower oil?

Multnomah County Oregon food safety home food preservation

1 Response

I am glad you are not doing any experimenting on your own when it comes to canning. This is especially true of low acid foods including all vegetables, meat, and fish. We have NO research based recommendations for canning low acid foods in oil that are tested for the home food preservation. Commercially they have many more options available than we do with our home food preservation equipment as well as all the variables that can happen in home kitchens.

You are right, heat penetration is much different in oil than in water. It doesn't matter whether it is vegetable or animal oils. The research was done with water so that is how they have come up with safe times and methods. To can in oil you would be guessing the processing time and that is never a smart idea.

The National Center for Food Preservation has researched based information on canning peppers that I suggest you follow.

Even though your theory on heat penetration sounds reasonable on paper I would not suggest trying it. Botulism is a very serious food borne illness that you wouldn't want to get by experimenting. Please stick to tested recommendations from reliable sources such as the OSU Extension Service, National Center for Food Preservation and commercially the Ball Blue Book.

If you have other food preservation questions you might like to call the OSU Food Preservation Hotline open M-F from 9 am-4 pm though mid October. Certified Master Food Preservers are available to answer you calls. The number is 1-800-354-7319.

Thank for using Ask an Expert.

Nellie Oehler