Sterilization 101

You have no choice: you must sterilize your jars if you want to store jam at room temperature without it becoming spoiled. Forget about the hard wax, oven or dishwasher used by our mothers and grandmothers. The only method to use is a boiling-water treatment. Here’s how in six easy steps:

  1. Place clean jars in a large pot and cover with hot water. Bring to a boil and let simmer for 5 to 10 minutes.
  2. Meanwhile, soak the lids in very hot (not boiling) water in a small pot in order to activate the rubber sealing edge. The lids are not reusable because the red band is only waterproof once.
  3. Pour jam into hot jars and leave 0.5 cm (1/4 inch) of head space for jam and 1 cm (1/2 inch) for fruit, marinade or chutney. Remove air bubbles with a rubber spatula and wipe the rim of the jar with a clean cloth.
  4. Place a lid on each jar, making sure it is centred, and screw the ring band on without over-tightening.
  5. Place the jars upright in a pot of water. Make sure they are covered by a least 2.5 cm (1 inch) of water. Cover. Bring the water to a boil, then calculate 10 minutes for jam, 15 minutes for a marinade (like chutney, ketchup, pickles) and 35 minutes for beets and tomato sauce.
  6. Remove the jars, making sure they remain upright and place them on a dish towel. Let cool 24 hours without tightening the ring bands. Check the seal. You should hear a “pop” sound (the lid is lower in the middle and does not move up or down when lightly pressed or tapped). This means there is no air in the jar and it has a strong seal. The jars will keep up to a year in a cool, dark place.

Good to know

For more information on canning, visit the Bernardin website at