When do you have to sterilize jars

Do NOT add cold food to hot jars, or hot food to cold jars; otherwise, the jar will shatter which is very dangerous. This method is the most-trusted method for ensuring your jars are scrupulously clean for your preserves. It takes slightly longer than the other ways but starts the process about 30 minutes before your preserves are ready to pot and you will not even notice the time.

This method works well for screw-top jars and the Kilner-style jars with a clip top and rubber rings. The dishwasher method is a good method for sterilizing your jars good if you have a high-temperature setting on your machine or a steam dishwasher.

Fill your dishwasher with clean cold jars and run a minimum or rinse wash to time the ending with when your jam, preserve or pickle will be ready. Use the jars one at a time from the dishwasher needed making sure you fill while the jam or preserve is hot as is the jar. This method works well for screw top jars and the Kilner-style jars with a clip top and rubber rings. This method of sterilizing is good for regular jam jars but not the Kilner-style or for metal lids.

Clean the jars as normal, rinse but leave the jars a little wet. Microwave for 30 to 45 seconds depending on the size of the jar. We recommend not using old jam jar lids if they are damaged or rusty, they should be thrown away as they may not make a good seal. Instead, use wax discs and cellophane or buy new lids. Spoon your homemade preserves into the hot jars and pack down well to remove any air bubbles. Place a waxed disc directly over the surface to create a seal, then add a lid or secure on a cellophane lid with an elastic band.

Watch our video on how to sterilise jars for a visual demonstration. Making homemade preserves for your storecupboard or as gifts? Our guides and videos are packed with expert advice:. Subscriber club Reader offers More Good Food. Sign in. Back to Recipes Pumpkin recipes Butternut squash See more. Back to Recipes Chicken slow cooker Veggie slow cooker See more. Back to Recipes Cheesecakes Cookies See more.

Back to Recipes Family meals One-pot recipes See more. Back to Recipes Quick and healthy Quick vegetarian See more. In addition to contamination by microorganisms that cannot be seen with our bare eyes, packaged jars may accumulate dust, small bits of debris, and even chips of glass in the case of breakage which does happen sometimes in all the steps of transport from factory to store to home.

Whether brand new or re-used many times over, you should always clean jars just prior to filling them when canning. Wash jars in a dishwasher or by hand, using detergent and rinsing well. Clean jars should then be kept warm prior to filling.

You can leave them in the closed dishwasher after the cycle, or use your canner as it is preheating, or create a separate water bath that will keep the jars both clean and warm.

Washing is also a good time to inspect jars for any cracks or chips, discarding or re-purposing those jars for non-canning uses if any imperfections are found. In order to actually sterilize jars, they need to be submerged in covered by boiling water for 10 minutes. When the process time for canning a food is 10 minutes or more at , feet elevation , the jars will be sterilized DURING processing in the canner.