Weck canning jars are made with thick glass to withstand boiling, sterilizing and processing over and over again. Glass lids preclude issues with rusting, and the tab on the replaceable rubber ring, when facing downwards, indicates clearly that the seal on the jar is intact.
The point of canning is to hermetically seal the outside world from the sterilized interior of the jar, preventing the food inside from spoiling. These jars are designed to make it easy to tell whether or not this all-important seal has been made.
Boiling the filled jars (also referred to as ‘processing’) and the cooling period directly afterward, creates a vacuum seal tight enough to keep invisible microbes from entering the jar. The strength of this seal alone is also what keeps the glass lids in place. After the jars have fully cooled, the stainless steel clamps are removed and you can check if the jars have sealed by lifting the lid. If it doesn’t come off, you know for sure the jar is sealed. If the jar didn’t seal properly, you can either re-process it, or refrigerate the jar and eat the contents within a couple of days.
All jars have wide openings for tidy, easy filling.
Canning itself is simple, but it does require gaining a good base of knowledge before you can do it confidently. Generally, canning involves putting a prepared food -- peach preserves, peeled tomatoes, green beans-- into a sterilized jar. The filled jars are then processed and vacuum-sealed and can be stored in a dim cupboard for a period of several months to a year, depending on what's inside.
If the jars aren't properly sealed or sterilized, the food inside will spoil or develop harmful bacteria.
Before using each Weck jar, run your fingertip along the rim and the sealing lid to check for chips and cracks. A new rubber ring is required each time. Check these for cracks by pinching the edges between your thumb and forefinger and running it along the ring's circumference. Any breakage in the sealing mechanism will prevent an air-tight seal from forming.
Just before putting the jars in the water-canner to process, the lids need to be held in place by a pair of spring-loaded stainless steel clamps. After the vacuum seal has formed and once the jars are fully cooled, the clamps can be removed and stored for next time.
To open the jars, tug at the rubber ring until you hear the seal release with a whizzing sound. The lids should lift off easily. Weck jars are made to stack in storage and are microwave safe.
All-glass jars have been around since the 1800s, but in the early days there was no way to tell if the jar was properly sealed until you opened it months later and found the contents rancid, or not. The design of these jars made it much easier to tell, and that much closer to making canning a more fool-proof, less disappointing endeavor.
Designer Johann Weck first released his jars on January 1, 1900. A vegetarian and teetotaler, Weck was adamant about devising a reliable, healthy and natural way of preserving anything from asparagus to blackberries.
6- or 12-pack of thick sided, elegant, all-glass jars. Six sizes. Made in Germany.
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