Bottling (canning in America) fruit and vegetables seems to be sadly out of fashion but, as explained below, most fruit and some veg can be preserved by simply pasteurising in the jar. Using a syrup of appropriate sweetness generally improves the flavour and gives a few extra days life once opened but it’s the pasteurisation that does the hard miles. Pam Corbin gives pretty good instructions and method and below is taken from her seminal River Cottage preserving handbook below:
“For bottling in this way, you need a pan deep enough to contain the jars completely submerged under water. The jars will crack if they sit directly on the base of the pan, so it needs a ‘false bottom’ such as a wire trivet or folded tea towel. A thermometer is essential t check the temperature.
The fruit should be packed into jars and filled to the brim with hot syrup (about 60c). If you’re using screw-band jars, the band should be released by a quarter of a turn for steam to escape. Place the jars in the pan and cover completely with warm water (38c). Heat to simmering point (88c) over a period of 25-30 minutes, then simmer for the time given in the recipe.
Remove the jars one at a time and place them on a wooden surface, newspaper or folded cloth – scooping out some of the water first will make it much easier to lift the jars from the pan. Tighten the bands on screw-band jars, then leave undisturbed for 24 hours until completely cool. Check the seal the following day.”