The Fowler’s Vacola preserving system heat seals jars to preserve food.
Jars filled with the food that you want to preserve are placed in a Fowlers preserving unit with lids on and covered with cold water. The water is then slowly heated until it reaches boiling point, which takes about an hour. It is then drained off and the jars allowed to cool.
Fowler’s make their own glass jars which have rubber ring seals and pressed metal lids, much like American Mason or Ball jars, except that the jars and lids are not threaded. Prior to the heating process the lids are secured to the tops of the jars with tension clips. As the jars cool a vacuum seal is created which holds the lids tightly to the top of the jars. The clips can then be safely removed.
The jars themselves are very robust and if you buy the stainless steel versions of the lids they will last you a lifetime. In place of the Fowlers jars you can also use Mason or Ball jars and any jar with an undamaged metal lid.
Fruit (such as apples, pears, apricots, and peaches) can be preserved as it has a high sugar content, though usually with a little sugar added for flavour purposes. Tomatoes can also be preserved as they are high in acid. Most vegetables cannot be preserved unless infused with a vinegar mixture.
Meat, fish, chicken or dairy products cannot be preserved using the Fowlers system due to the risk of botulism! For these foods you need temperatures higher than boiling point, which can only be achieved with a canning pressure cooker.
If using the Fowlers preserving method make sure you read the instruction booklet that comes with each unit carefully to ensure that you are preserving the right types of food in the proper manner.
FOWLERS JARS LEFT TO RIGHT: No 14 (350 ml), No 20 (600 ml), No 27 (800 ml) jars and No 31 (1 litre) jars. The number 27 jar is no longer made by Fowlers but still can be bought second hand. In the foreground are the two sizes of lids, rubber seals and tension clips that are used to seal the jars.
Other types of jars that can be used
LEFT: Two sizes of Ball jars and a Ball jar lid. RIGHT: Assorted metal lidded jars with jam in them. Any jar with an undamaged metal lid can be used to preserve food in a Fowlers unit.