A clean sterilised jar is essential to the success and longevity of the jams and preserves you spend a lot of time making. It is important to sterilise any jars used for preserves to remove any bacteria, yeasts or fungi to protect the food you put into the jar. Dirty or jars that have not been sterilized properly will infect the food inside and it will spoil very quickly and need to be thrown away.
Sterilizing is quick and easy therefore should never be omitted. Here are two simple ways to achieve a good sterilization.
Important Note About Sterilising Jars for Jam and PreservesDo NOT add cold food to hot jars, or hot food to cold jars otherwise the jar will shatter which is very dangerous.
Time Required: 30 minutes
My favourite method.
Heat the oven to 275°F/130°C/Gas 1 - don't be tempted to heat the oven any higher or you may risk the glass breaking. Lay a double layer of newspaper on each oven shelf but not the floor of the oven. Arrange the jars on the shelf making sure the jars are not touching each other. Close the oven door and sterilize the jars for a minimum of 20 minutes. Using thick oven mitts, remove each jar from the oven as needed onto a heatproof mat or heat pad, making sure you fill while the jam or preserve is hot as is the jar. ***Do NOT add cold food to hot jars, or hot food to cold jars otherwise the jar will shatter.
The dishwasher method is good if you have a high temperature setting on your machine, or as I do, 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. Do NOT add cold food to hot jars, or hot food to cold jars.
In the Microwave
Clean the jars as normal, rinse but leave the jars a little wet. Microwave for 30 - 45 seconds depending on the size of the jar.
- I 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.
- Want to see how to sterilise your jars, watch my short video showing you how.
- As already mentioned several times above, do NOT add cold food to hot jars, or hot food to cold jars.
- Remove jars from the oven or dishwasher only when needed or they will cool down too much.
- Always sterilize more jars than you think you will need. Should you have more mixture than anticipated it is too late to start sterilizing once the food is ready.
- Leave jams, preserves or pickles to settle for 15 minutes before sealing.
What You Need:
- An oven or a dishwasher
- Clean jars or bottles
- Thick oven mitts or heatproof cloth
- Heatproof mats or pads
- Wax discs, cellophane covers or new lids