When making large quantities of jarred foods (i.e. pepper spread, homemade tomato sauce), you need to preserve the goods. To avoid contamination, the jars have to be airtight sealed. If they are not properly sealed, the food can go bad, or worse, botulism can contaminate the product. Luckily, sealing jars is simple and quick. This way of sealing jars is shared by a cook who uses it often, canning more than 100 jars of homemade tomato sauce a year.
Pour the food into the jar.
Place the topper (the circular lid that rests on the top of the jar) on the jar. Make sure is in on properly (not off center) and is secure.
Put the lid on top of the jar and topper and screw it on. Screw it so it is tightly on the jar.
Place jars in the the rack in the boiling-water canner. Run water into the canner until it fills just slightly over the jars. Make sure the jars are immersed in the water.
Put the canner on the stove (do this carefully, it will be heavy), and turn the stove on high.
Allow the water to come to a boil. Once it starts to boil, let it continue to boil for eight to 10 minutes.
Put the canner to the side to cool off when time is up. Carefully, but quickly, pull the jars out of the water and place them to the side. Avoid putting them on a glass dish, which could crack the dish, or in the refrigerator, which could crack the jars. Allow the jars to cool before storing.
To make sure the jars have been properly sealed, the middle of the jar topper will suck in slightly. When you open the jar, it will pop up and make a little popping sound.