How to Vacuum Seal a Mason Jar

When canning at home, sealing the glass jars properly is extremely important.

Not only does it keep the contents inside fresher for longer, it also keeps the contents safe from harmful bacteria. Canning by boiling food-filled Mason jars is an easy and a quick way to ensure fresh, healthy and safe food.

Fill the stockpot or canning kettle with water. Bring the water to a boil.

Fill the jars with the food being preserved. Do not fill the jar all the way up to the top; the food can expand in the canning process and cause the glass jar to crack or break. Instead, leave 1 inch between the food and the top of the jar.

Place the lid on top of the Mason jar with the seal resting against the rim of the jar.

Screw the jar band, also called a ring, onto the jar and over the sealer. Make sure the band is screwed on tightly. Heat will soften the seal and secure it against the jar.

Turn down the heat under the stockpot so that you can place the jar into the stockpot. Repeat this process with as many jars as will fit into the kettle. Make sure the waterline stays 2 inches above the jars.

Return the water to a boil and process the jars (appropriate boiling times for some commonly canned types of food are given in the Tips section). When the time is up, move the pot to cool off. Once cooled, take the jars out and set them on a dish towel.

Store the jars in a pantry or cellar once they have completely cooled. Since they are vacuumed sealed, they do not need to be stored in the refrigerator until after opening.

Things You Will Need

  • Stockpot or canning kettle
  • Water
  • Glass Mason jars
  • Food to be canned
  • Lids with seals
  • Jar bands
  • Dish towel

Tips

  • Use the following times for canning:
  • -5 to 10 minutes for pickles
  • -10 minutes for jam
  • -20 to 30 minutes for fruit, fruit pie fillings, and applesauce
  • -30 to 45 minutes or more for tomatoes

Warnings

  • Do not put the jars directly into the refrigerator, as the heat inside the jar can cause the glass to crack when abruptly cooled.
  • Botulism is a serious and life-threatening illness caused by a bacterium that can contaminate improperly canned foods. For more information on botulism, visit the Centers for Disease Control website.

About the Author

Andrea Griffith has been writing professionally since 2005. Her work has been published by the "Western Herald," Detroit WDIV, USAToday and other print, broadcast and online publications. Although she writes about a wide range of topics, her areas of expertise include fashion, beauty, technology and education. She holds a Bachelor of Arts in journalism and English from Western Michigan University.