To sterilise jars
- Place the cleaned jars on their sides in a large boiler or saucepan; cover with cold water.
- Cover the pan and bring to the boil over high heat; boil for 20 minutes.
- Carefully remove jars from water; drain.
- Stand, top-side up, on a wooden board. The heat from the jars will cause any remaining water to evaporate quickly.
- Stand the clean jars, top-side up, on a wooden board placed in a cold oven (do not allow the jars to touch); heat oven temperature to very slow (120°C/100°C fan-forced), then leave the jars in the oven for 30 minutes.
To seal jars
Which lid do I use?
- Metal lids are not suitable unless they have a protective plastic insert or liner to prevent corrosion.
- Plastic screw-top lids give a good seal (plastic snap-on lids are not airtight enough). Plastic lids must be well washed, rinsed and dried, or put through the dishwasher.
- Some older preserving outfits have glass lids; these can be sterilised in the same way as the jars.
- Do not use aluminium foil, cellophane or paper covers for preserves; acid in the preserves will corrode foil, while paper and cellophane are not airtight enough for long-term keeping.
- Melt wax slowly in a small saucepan over low heat. It is important not to overheat the wax or it will shrink on cooling, giving an imperfect seal.
- Pour a thin layer over the top of the cooled preserve, about 2mm thick, just enough to cover the surface. Leave until almost set, then pour another thin layer on top of the first layer.
- Insert small pieces of string in the wax just before it sets to make it easier to remove wax.