Tomato Relish 2 : Canning

I really enjoyed the canning process so I thought I’d share it here. It might be a useful reference for some of you that are curious about it to see the steps visually. Hot water canning is only suitable for acidic foods, which is why I opted to do a tomato relish instead of a jam — and there are specific processing times, head rooms for every jar size and type so make sure you check the details and only use this as a guide.

Things you’ll need:

Canning jars (regular jars are not designed to withstand such temperature changes)
3-4 large pots
Tea towels
Wooden chopping board/trivet
Canning kit (Funnel, magnetic wand, tongs etc.)


For these I used 4oz quilted jam jars from Ball, they come with lids and bands and were great to use. The jars and bands can be reused, but the lids are one-time use only. Start by boiling lots of hot water in a kettle and get some large pots ready to go. Separate the jars from the lids and bands. I also bought a canning kit, which comes with a wide funnel, magnetic wand for lids, and several types of tongs to pick up jars from hot water. I found that these tools make the job not only easier, but also much safer.


The first step is to sterilise the jars and lids. Bring hot water to the boil in pots and bring the flame down to a simmer. Keep the jars and lids in a simmer while you work.


Here are the lids sitting in simmering water. The adhesive on the underside softens in the heat.


The jars should also be sitting in simmering water until you’re ready to fill them.


Bring the relish back to the boil if it has been cooled before. Make sure that the whole batch is heated through.


Most canning kits will come with a wide mouth funnel which is really useful in keeping the jars clean. Pour relish into the jars carefully, leaving 1/2″ of room at the top. Remove the funnel and tap onto the bench to release any air bubbles. Wipe the top rim of the jar to ensure it’s dry and clean.


Use a magnetic lid wand, if you have one – to pick up a lid from the pot and place on the jar.


Place a band on the jar, only closing the lid to “fingertip tight”, ie. not cranking the lid as tight as it will go. There needs to be some give so that air can leave the jar and create a vacuum. I like to hold the lid in the middle with my left hand to make sure the adhesive is in contact and the lid is centred on the jar.


To process the jars, place a tea towel in the bottom of a large pot of boiling water. For each jar size processing times will be different; for these it was about 45 minutes. Once 45 minutes is up, remove the jars from the water and place on a trivet or something heatproof for about ten minutes. Here you will here the lids pop as the vacuum forms inside the jar! You can try to count the jars that have popped, but it’s fairly easy to tell as the lids will be sucked downwards and create a little concave on the lid. Once they have sat out for ten minutes, dry the jars and this time, tighten the lids as tightly as you can. Check that the lids have sealed correctly, and then they should be safe to keep in a cool, dry place for up to one year.


Here are our jars packaged with labels that we designed – and we gave them away with wooden spoons from Japan!