The normal and natural spoilage of fruits, vegetables and meat is caused by micro-organisms, which are circling through the air. During preserving, the micro-organisms are killed inside the jar. Through the heating process arises an overpressure. Glass lid, rubber ring and clamps act like an overpressure valve: they let go of air, steam and eventually liquids from the inside of the jars and nothing can get inside - no air and no cooking-water (fig. 1). During cooling process, a vacuum arises inside the jar. The clamps are now redundant and have to be removed (fig. 2). Now you can check, if the jars are closed. If the content spoils later, carbon dioxide push open the glass lid. This is a significant sign for you, which saves you for eating cluelessly spoiled food.
(fig. 1) Fill the jar approx. 1 cm under the edge.
(fig. 2) Turn over the glass lid, so that the writings and WECK® strawberry are pointing upwards.
(fig. 3) Turn over the glass lid again and put it with the rubber ring onto the jar.
(fig. 4) Seal the lid with 2 clamps. Set.
(fig. 5) During preserving, the topmost jar (or the highest one) has to be fully covered with water. The sealing-up rubber ring prevents the incoming of water during preserving.
(fig. 6) After preserving, remove clamps. If the jar is closed tightly, the preserving was successful, the content is safe.