If you listened to last week's podcast, then you know that new research supports steam canning as a safe, effective, and approved way to home can. Yay! And me being me, I had to get my hands on the research paper the supports the change in the USDA's recommendation on steam canning.
Why do we want to use safe practices when home canning? Because we don't want to be on the wrong side of lethality--the killing of the microorganisms that can cause illness and death when left to grow in an improperly canned food. It's all about heat transfer, convection heating, conduction heating, and air cooling rate.
As with many things that are not approved, it can be because there isn't research or adequate research to provide safe guidelines or because research makes it clear that it isn't safe.
The case with steam canning was incomplete research. But, we now have the data to support steam canning!
Okay, that's interesting. What does this mean to you, the home preserver? Steam canning can now be safely added to your food preservation line-up. Why would you bother with another piece of equipment:
- Saves water. Less water is needed in the canner.
- Saves time. Steam canning generally takes less time because there is less water to heat and the canner reaches the temperature required for canning faster.
- Saves energy. Since the canning process is faster, less energy is required.
- Do not rely on guidance that may accompany your steam canner. Use the current guidance.
- Hot pack jars and keep the jars warm.
- Steam canning is never a substitute for pressure canning. Ever.
- Tested boiling water canning recipes are suitable for steam canning.
- And to rephrase. Steam can high acid foods--these are the same foods that have been tested as safe for boiling water canning.
- Processing time for steam canning batch should be limited to 45 minutes or less so that the canner doesn't run dry. That would be sad!
- Always avoid canning mistakes and check current guidance!
Be safe and eat well!
Thank you Dr. Barbara Ingham, University of Wisconsin-Madison for sharing the research.
Willmore, P., M. Etzel, E. Andress, B.H. Ingham. 2015. Home Processing of Acid Foods in Atmospheric Steam and Boiling Water Canners. Food Prot. Trends. 32:150-160.
- National Center for Home Food Preservation, Using Atmospheric Steam Canner: Can acid foods be processed in steam canners?
- University of Wisconsin-Extension, Safe and Healthy: Preserving Food at Home, Safe Preserving: Use an Atmospheric Steam Canner
- Kansas State Research and Extension, Preserve it Fresh, Preserve it Safe.
- University of Wisconsin-Extension, Safe and Healthy: Preserving Food at Home
- USDA, National Center for Home Food Preservation, Complete Guide to Home Canning (2009 version)
- Utah State University Extension, Food Preservation Fact Sheets