I was talking with a canning veteran about food preservation the other day and she said in a forboding voice, "Don't can green beans." The implication was that it isn't safe to can a low acid food like green beans because of the risk of deadly and debilitating botulism. The truth is that low acid foods are safe to can as long as you follow tested recipes from here, here, or here. It is also true that improperly canned low acid foods can be deadly.
The key to safely canning low-acid foods is the proper use of a pressure canner which will get the foods to the 240-250 degrees necessary to kill botulism. You can use a pressure canner with a dial guage, that shows a number reading of the internal pressure, or a pressure canner with a weighted-guage that makes a jiggling noise when at proper pressure. The plus side of a dial guage is more flexible adjustments for needed pressure, especially when you need to make adjustments for altitude. For example, if a processing recipe at 2,500 feet of elevation calls for 12 pounds of pressure on a dial guage you can make the adjustment with some precision. Your only option with a weighted guage is to use the 15 pound setting. The down side of a dial guage canner is that it must be tested every year for accuracy and in general is less precise than a weighted guage.
I'm going with the weighted guage. I've been told that there is minimal loss of quality using the canner at 15 pounds, and I have more of a comfort level with the weighted guage being more accurate.
Here are some things to know about canning low acid foods.
- It is important to vent the canner for 10 minutes to get out air pockets. This includes "self-venting" canners. Otherwise the food will be under-processed.
- It is recommended that all properly canned low acid foods be boiled before eating for 10 minutes to ensure safety. Above 1,000 feet of elevation add a minute for every 1,000 feet.
- The cool down time is not optional. It is actually part of the processing time built into the recipe. (30 minutes with pints and 45 minutes with quarts in older canners. New canners have a vent lock indicator.)
- Loss of liquid may be caused by fluctuations in temperature during processing.
- Yellow,gray or black crystals on asparagus are probably rutin, a safe, naturally occuring pigment.
- If the pressure sinks below the recommended pressure during processing you've got to bring it back up to pressure and make sure it is processed at the proper pressure without interruption for the entire processing time.
- I've been told canned meats, beef especially, and stews are very good when pressure canned.
- "Pressure cookers" should not be used.
- Canning Seafood pdf
- Instructions for canning asparagus, beans or peas (shelled), snap beans, beets, carrots, mixed vegetables, peppers, soups, and others.
- Instructions for canning poultry, red meats, and seafood (including chili)
- Special instructions for canning pumpkin
- Resources for preparing Venison
- Using and Caring for Your Pressure Canner