The canning world has seen little change since Nicholas Appert first came up with the idea in the late 1800s. Basically, you seal the containers, heat up the inside and when cooled, form a vacuum seal on the jar. Now, there are quite a few different ways to can, as well as different requirements for canning certain items. Let’s take a look at how canning works.
There are two main types of canning; boiling water and pressure. Different types of foods, based on their pH level, use a specific type of canning. For instance, ripe plums can use a boiling water canning process, while most tomatoes absolutely must use pressure canning.
There are four main parts to canning, with numerous others for various tasks associated with canning, but for simplicity, we will focus only on the jar, lid, ring and heating device. For home canning, glass jars are the most popular choice. Canning in the industrial setting uses the steel alloy cans you see on your supermarket shelves. Glass jars can withstand heat and pressure and, if thoroughly cleaned, can be reused every year.
Lids, on the other hand, cannot be reused as they are the main sealing component and once they are sealed, the gasket begins to wear down. The ring holds the lid on during the heating process and can be reused as well. The heating device, well, heats everything up.
The heating process is the most crucial part of canning. Once the jars are filled and lids and rings placed tightly on, the jars are placed in the heating device. As the heating begins, the foods in the jars begin to expand and give up a little water in the form of steam, pushing air out of the jars.
Different foods require different amounts of heating and time. For instance, tomatoes will require pressure canning for about ten minutes while the ripe plums can be canned in a boiling water bath for fifteen minutes. Making sure you heat for the required time ensures that mold, yeasts, bacteria and any harmful enzymes that may be hanging around are killed.
Once the jars are removed from the canning device, they begin to cool and the steam condenses back into water. Since there is now less air in the jar, a vacuum is created, pulling the lid down onto the can. After the product has been cooled, the ring can be removed and the vacuum seal will still hold.
It is important to allow the items to cool thoroughly before you remove the rings to ensure a proper seal. Also, once cool, it is imperative to check the lids to make sure the seal took and there are no openings in the top of the jar. If there is a leak, be sure to consult your canning manual for what to do with the canned goods.
Knowing how canning works allows us to make sure we have the best outcome in our canning process and also gives us a way to understand if everything worked the way it should have. Make sure you have all the needed items before you begin canning to ensure a great experience. Go pick out some fresh produce and get to canning.
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