This must be done when preserving food. There are various ways to sterilise you jars before putting your lovely jams and chutneys into them. I use the first method.
- Wash the jars in soap and hot water and rinse clean. Allow them to drip-dry, upside down in the oven set to 140 C 275 F Gas 1. I usually put the jars straight onto the oven rack) Leave them for at least 30 minutes while you make the jam.
- Run through a dishwasher cycle, making sure the jars are still hot when its time to pour the jam into them.
- Put the jars into boiling water and boil for 10 minutes.
Don’t forget to sterilise the lids too.
The setting point literally means when the jam begins to set. Once its boiled for long enough the magic happens and it starts to set. If the jam doesn’t set it will remain runny. You can tell by sight when the jam is beginning to set as it starts to bubble differently as the mixture is thickening, the bubbles plop more. Also if you run your stirring spoon through the middle of the mixture a channel will be left for a little longer. However these tips are by sight only and sometimes let you down. The best, most reliable way is to do the saucer test. Before making your jam put 3 saucers into the freezer. After 5 minutes of hard boiling or as the recipe states take the jam off of the heat and test for setting by putting a teaspoon of jam onto one of the frozen saucers. Leave to cool for a minute and test for setting by pushing your finger through the jam. If the jam doesn’t immediately fall back into place or wrinkles and even better a skin has formed, it is set. If not, return to the heat for 2 minutes and repeat. Usually 1 or 2 repeats are all that’s necessary. Of course the opposite to under setting is over setting which results in jam that is unusable so better for a slightly runny jam that can be used in other ways such as a sauce for ice cream.
This is a process where jars of home preserved foods are heat-treated to preserve for longer. It seals the jars avoiding spoilage by air contact.
In the UK after making jam its most common to top your jars with a waxed disc, seal the jar and put it away until you need it. In the US after putting the jam in jars a canning procedure is followed to avoid botulism. I remember my mother scraping the mouldy bit off the top of jam and using what was underneath and we never got sick! However as I like to give my jam and pickles as gifts sometimes I feel its safer to follow the canning procedure. It doesn’t take long and gives peace of mind. Here are my tips on how to “can” and some links to help you further
I use the water bath method, here’s how you do that;
I don’t have a special canning pot (hard to find in UK) I use my largest stock pot.
You need something on the bottom of your pan so the jars don’t rattle around or fall over while in the boiling water. If you have a canning pot it probably came with a rack especially for that purpose (again hard to find in the UK) for those of us with no rack the most common advice is to put a towel/dishcloth on the bottom of the pot. I am lucky enough to have a round cake cooling rack bought in IKEA long ago, it covers the bottom of my stockpot perfectly.
- Fill the pot you are using with water and bring to the boil.
- After filling your sterilized jars with jam, chutney etc. screw on the lids but not too tightly as air needs to escape from the jar. Wipe jars clean.
- Place jars into boiling water, put the lid on the pan and boil the jars for a specified time. The time varies according to what is inside the jars.
- After the specified boiling time, turn off the heat and leave the jars in the pan for a few minutes.
- Carefully move from the water and to cool place onto a tea towel (to avoid possible cracking due to a cold surface). I usually leave overnight. You may here the jars popping, this is also referred to as “pinging” its the most rewarding sound when canning as it means our jar has sealed!
- Really that’s it! To check your jars press the lid and it should not move up and down, the canning procedure seals the jars.
For further, more detailed information go to the Ball canning site Ball is the big name in canning in the US. The products are not available to buy (yet) in the UK but the advice is very useful. If you look at the recipes on that site it will guide you as to how long to boil different food for.