Canning may seem like an intimidating process when you’ve never done it before or at least seen someone doing it at home. But following this simple guide will make you love canning your homemade jams, tomato paste, or pickles.
I’ve known ever since I was a child that homemade jam, tomato sauce, roasted bell peppers, and pickles should be preserved to last over the winter. My mother did this then, and she still does it every end of the summer and during the fall.
I didn’t know at that time, but now I am aware that food preservation prevents the growth of microorganisms, as well as slowing the oxidation of fats that cause rancidity. For example, when we try to preserve fruit in the form of jam, we need multiple processes. First, we boil it, to reduce the fruit’s moisture content and to kill bacteria, then we sugar it, to prevent the re-growth of the bacteria, and finally, we seal it within an airtight jar.
The only way to obtain a longer shelf life is to can at home. Although we usually can foods to last from fall to spring or the next summer, canning typically makes the foods last from one to five years. My mother still has jam jars in her cellar that she canned 3 years ago.
How did canning start?
Canning was invented by the French confectioner Nicolas Appert and involves cooking food, sealing it in sterilized jars, and boiling the containers to kill or weaken any remaining bacteria as a form of sterilization.
Appert was a confectioner and chef in Paris from 1784 to 1795. In 1795, he began experimenting with ways to preserve foods and he succeeded with lots of items: soups, vegetables, juices, dairy products, jellies, jams, and syrups. He placed the food in glass jars, sealed them with cork and sealing wax, then placed them in boiling water.
As a funny aside, in 1800 Napoleon offered a prize of 12,000 francs for a new method of preserving food and Appert presented a selection of bottled fruits and vegetables in 1806, but he didn’t win any reward. Still, in 1810 the Bureau of Arts and Manufactures of the Ministry of the Interior gave Appert an ex gratia payment of 12,000 francs on the condition that he make his process public. Appert accepted and published a book describing his process later that year.
How to succeed with canning at home
At first, canning may seem intimidating. After all, why to do it yourself since you can have anything you want from the market? Well, because homemade foods are always better than store-bought ones, you can make them to your taste, and it’s comforting to have them in your pantry throughout the cold season! You just make that jam and we’ll tell you how to succeed with canning, don’t worry!
1. Sterilize your jars
How many jars are you going to need? After you decide on the answer to that question, wash the jars and then sterilize by boiling them for 10 minutes. Put your lids in a small saucepan filled with water and bring them to a simmer too.
2. Fill them up
Use a ladle and add the hot jam or pickling liquid into the jars. You can also use a wide-mouth funnel to fill the jars. Make sure you leave enough head space (based on your recipe or about 0.8-inch/2 cm). Clean the rim with a damp paper towel.
3. Put the lids on
The next step is to place the lids on each jar and then screw the band on just enough to hold it in place. Don’t make it super tight, because the contents can expand, and if there’s no room to move, the jar might crack.
4. Prepare one pot for sterilizing jars
Line the bottom of a large pot with a kitchen towel. The purpose of making this is that the towel will protect the jars from moving and cracking. Fill the pot with about 4-inch/10 cm of water. Bring the water to a simmer, then carefully lower the jars into the pot, spacing them about 1-inch/2.5 cm apart.
5. Add hot water if necessary
If the water does not cover the jars by 1–2 inches/2.5-5 cm after adding them to the pot, use more boiling water to submerge them. You can either have a kettle going or have a small pot of boiling water to help with that. Keep in mind that you want to sterilize the entire jar, including the lid, so they should be fully submerged!
6. Simmer the jars
Simmer the filled jars for 10–20 minutes, depending on the recipe. Usually, for fruit jams, 10 minutes are more than enough. Remove them with a jar lifter that has a rubber grip and place them about 1-inch/2.5 cm apart on a towel-lined surface. Let them cool. Some people just remove the pot from the heat and leave the jars to cool gradually, with the water.
7. Test the seal
Once the jars are completely cool, test the seal by pressing on the lid. It shouldn’t flex up and down, but if it does, that means some air got trapped in.
8. Label and store the jars
Label the jars and store them in a cool, dark place. They’ll last for up to a year.