I discussed unsafe canning methods in the podcast and show notes, Botulism & Unsafe Canning Methods - PVP29.
But, it's so important that it bears repeating. If you only want the new bits then scroll down to the Final Words.
Never Substitute Water Bath Canning for Pressure Canning
From 1931 to 1942 the USDA gave its stamp of approval to oven canning. In 1944 the USDA issued a warning against oven canning. Here's the deal: oven canning involves dry heat. Dry heat doesn't penetrate the jars and the food in the same why as moist heat. Okay, so? Well, that means that the cooties that cause illness and death are not going to be killed during oven canning. Plus, there are zero, zilch, no guidelines for oven canning. Plus, jars may crack and explode. In other words there are no data to support home canning in an oven. Yes, we could go on about what if scenarios--but the bottom line is no current research, no current guidance, thus no safe recipes for home canning in the oven.
Microwave Canning & Dishwasher Canning
Microwave canning and dishwasher canning. Both of these just make me go, huh? Why do we insist on innovating in the kitchen? It isn't the same as cooking a roast in the oven or on the stove top or in the microwave or in a crock pot. The underlying problem with both of these methods are: heat penetration to kill the cooties just isn't present or consistent. There are no tested methods or recipes using a microwave or dishwasher for home canning.
Canning powders are interesting to me--I wonder how we arrived at thinking this might be a good idea. Canning powders could be labeled "Not Safe Since 1917". Yup, a century ago scientists determined that canning powders had a minuscule if any affect on controlling the growth of microorganisms as part of canning. Canning powders contained boric acid, salicylic acid, and salts or a combination of one or more ingredients. Interesting but completely not safe. Like so many things we people "rediscover" an idea and run with it--in this case, don't!
Open Kettle Canning
Oh gosh, the jam and jelly purists are going to be upset. Bottom line here is that cooties are simply not excluded using the open kettle process. I recommend eating that wonderful, delicate jam today and storing the leftovers in the fridge.
And finally, if the boredom or curiosity is sweeping over you, can delve into all the gory details of the history of home canning by reading Critical Review of Home Preservation Literature and Current Research. The lead author, Elizabeth Andress, is also one of the authors of a reliable canning book: So Easy to Preserve available from the University of Georgia. Penny up $18.00 for a terrific book full of safe recipes and good information!
There are other unsafe canning methods including compost heap canning, solar canning, and crock pot canning. But, following reliable recipes and using tested, approved practices is the most safe, reliable route in home canning.
Yes, it takes time to learn to can, you need to be ready to home can, and all that good stuff. But, controlling what is in the jar to create wonderful, shelf stable, economical products is impactful on the homestead. Virtually no waste, no trash, nothing to recycle--except we are all trying to figure out what to do with those pesky metal lids that we should never reuse.
One of the biggest concerns amongst home preservers is botulism. Many folks don't home can beans or fish or meat or soups because of the fear/concern regarding botulism. And I get that. But, by following a few rules, botulism is easily avoided while the pantry shelves are full.
- Always pressure can low acid foods
- Always use a reliable recipe
- Always select appropriate jar size(s)
- Always process for the specified length of time
- And when in doubt, toss it out!
Look at the photographs so far in the Weekend Preserver Series--we have millions and millions of jars of experience pressure canning!
Be safe and eat well.
Please be aware of acceptable modifications (University of Wisconsin-Madison Extension PDF, May 2015) that can be made to a home canning recipe--keep in mind that not all modifications, even popular ones are safe!
If you are ever in doubt regarding safety, be sure to check a reliable resource. Even recently published books might contain recipes that are not suitable for safe home canning
- USDA, National Center for Home Food Preservation, Complete Guide to Home Canning (2009 version)
- Check out university extensions (these are just a few):
- Order a copy of So Easy to Preserve from the University of Georgia. $18.00 shipping included has everything you need to be a safe home canner.