Canning (or bottling as it’s also known) is a fantastic, cost-effective way to store garden produce. This low-tech method of preserving uses heat to kill off any microbes that might spoil the food. Then, as the jar cools, a vacuum seal is created that keeps the contents fresher for longer.
This video explores the simplest method of canning: water-bath canning, which can be used to preserve a wide variety of fruits, jams, pickled vegetables, salsas and tomatoes.
The secret to successful canning is ensuring a strong seal between the jar and its lid, which if broken serves as an entry point to bacteria and mould. A loud hissing sound on opening a jar indicates a release of pressure from food that’s turned bad. Mould, froth, discoloration and bad or unnatural smells are other warning signs.
Water-bath canning is great for foods with a high acid content - many fruits, for instance. Vegetables are naturally low in acid, so must be pickled in a vinegar solution before canning in order to raise the acidity. Tomatoes, although acidic, are on the borderline of what’s considered safe, so they should also have an acid added – lemon juice is often used. This reduces any risk of botulism, a rare but serious illness caused by food that hasn’t been stored correctly. Follow recipes very carefully!
To get canning you will need a large water-bath canner or stockpot, a canning rack or a dish towel to keep jars off the bottom of the pot, a jar lifter or canning tongs, and a wide-mouthed funnel. You’ll also need a spatula, ladle, some dish towels and some canning or mason jars with accompanying lids and bands.
Sterilising Canning Jars
Begin by cleaning the jars in hot, soapy water, then rinse. To fully sterilise the jars you have two options: submerge them in water, bring to the boil then simmer for 10 minutes. Or pop the jars onto a baking sheet and into an oven preheated to 300ºF/160ºC/Gas Mark 2 for 10 minutes. Keep the jars hot until you’re ready to fill them to prevent the glass cracking. Prepare the lids by soaking them in very hot but not boiling water. The bands need no preparation.
With that done, it’s time to get the water bath ready for the filled jars. Fill your pot or canner halfway with water, put it on the heat and bring the water up to a simmer.
Retrieve your hot jars then fill them with your chosen recipe. Whatever the recipe, take a moment to remove any air bubbles by sliding a spatula between the food and jar to release them. If necessary, top up with a little more of the vinegar solution.
Water Bath Canning
Wipe clean the threads of each jar if there’s been any splashback. Carefully place the hot lids then screw on the bands, firmly but not too tightly. Position the jars on the canning rack so they aren’t touching then lower the rack into the simmering water, or just place them on a folded-up dish towel on the base of the pot. The jars should lie about an inch or 3cm below the surface. If needs be, top up with more water. Turn up the heat to bring the water to a rolling boil then continue boiling for the time stated in the recipe.
When the time’s up, turn off the heat and, after another five minutes, remove the jars from the water and onto a dish towel. Leave them be for 24 hours as they cool back down to room temperature. You may hear the lids pop or ping as the vacuum develops to create the seal.
Storing Your Canned Goods
Once cooled, check that all the lids have sealed by removing each band in turn then pressing down on the center of the lid. There should be no give. If there is, refrigerate the jar and make sure to eat the contents within two weeks. Store the successfully sealed jars somewhere cool, dry and dark where they should keep for at least a year.
Once you get the hang of it, canning is a fantastic way of locking in that wonderful taste of summer. Try it for yourself, and why not share your creations with friends and loved ones as the perfect gift.
What’s your favourite crop for canning and do you have a go-to recipe? Let us know down below.