How Much Pressure -- 10 or 11 pounds?
Posted: July 11, 2012
It is correct to use 10 pounds pressure to process foods in a weighted gauge canner. For dial gauge canners, process the food at 11 pounds pressure.
There is a difference in the two types of canners making it necessary to increase the pressure in a dial gauge canner. USDA recipes specify which pressure to use for each type of canner. Recipes in the Ball Blue Book® give directions for a weighted gauge canner, but a chart in the front of the book indicates that you need to increase the pressure by one pound if you are using a dial gauge canner.
All USDA recipes process meats, low acid vegetables and acidified tomatoes at 10 or 11 pounds depending upon the type of canner. Fruits are processed at 6 pounds pressure in a dial gauge canner and 5 pounds in a weighted gauge canner. Refer to a research based recipe for the length of time to process each specific food.
Do not use out of date recipes for pressure canning. Some old canner books may specify other pressures. That is an indication that the recipe was developed prior to 1994 and may not include processing times or pressures adequate to destroy all spoilage organisms and especially Clostridium botulinum spores.
Note: These pressures are for canning at altitudes below 1000 feet above sea level. You must increase the pounds pressure if you live more than 1000 feet above sea level.
Visit the Penn State Food Preservation web site at http://extension.psu.edu/food-safety/food-preservation or your local Penn State Cooperative Extension office for tested recipes that give processing times and pressures.
Use the web site to find your elevation; click on Food Preservation Tools, then USGS elevation finder.