The machine used in canning is called a canner. There are different types of canners that are used for different purposes in the canning process. These include boiling water canners, atmospheric steam canners, and pressure canners.
Boiling water canners are typically used for processing acidic foods, which have a pH of 4.6 or lower. These canners are designed to hold either 7 quart jars or 8 to 9 pint jars. They are made of a large pot with a lid and a rack that sits at the bottom to prevent the jars from directly touching the heat source. The canner is filled with water, and the jars are placed on the rack. The water is then brought to a boil and maintained at a specific temperature for a set amount of time to ensure proper processing and preservation of the food.
Atmospheric steam canners are also used for processing acidic foods, but they use steam instead of water for heat processing. These canners are designed to hold the same number of jars as boiling water canners. They have a larger pot with a lid and a rack, similar to boiling water canners. The difference is that atmospheric steam canners have a vented lid that allows steam to escape during processing. This helps to create a more controlled environment for heat processing acidic foods.
Pressure canners, on the other hand, are used for processing low acid foods, which have a pH above 4.6. These canners are designed to hold the same number of jars as the other types of canners. They have a larger, heavy-duty pot with a locking lid and a pressure gauge. Pressure canners work by building up steam pressure inside the pot, which raises the temperature above the boiling point of water. This high temperature is necessary to kill bacteria and other harmful microorganisms in low acid foods. The pressure is maintained at a specific level for a set amount of time to ensure safe processing.
In my personal experience, I have used both boiling water canners and pressure canners for home canning. I have found the boiling water canner to be relatively easy to use and suitable for processing acidic foods such as jams, jellies, and pickles. The pressure canner, on the other hand, requires more attention and careful monitoring of the pressure and processing times. However, it is necessary for preserving low acid foods such as vegetables, meat, and poultry.
The canner is an essential piece of equipment for heat processing home canned foods. It allows for the safe preservation of a wide variety of foods, extending their shelf life and ensuring their safety for consumption. Whether using a boiling water canner, atmospheric steam canner, or pressure canner, it is important to follow proper canning guidelines and instructions to ensure successful and safe canning results.