Canning pot
A boiling pot (also known as a boiling pan or a boiling apparatus ) is a kitchen appliance required for boiling down . It is used to heat the jars in a water bath, which sterilizes the contents of the jars and creates a negative pressure in the jar, which keeps the lid of the jar closed.
The very first jars offered by Johann Carl Weck as accessories for his mason jars corresponded to the models that are still common today. These are pots with a capacity of about 30 liters, which are usually provided with two handles and are heated on the stove. There is a hole in the lid through which a thermometer can be inserted. With the help of this thermometer, the temperature of the water bath can be controlled as it has to be adapted to the food to be cooked.
The first cooking pots included an insert that consisted of a round, perforated sheet metal plate, the diameter of which corresponds to the inner diameter of the pot. In the middle of the plate there are several rods that lead into a handle at the top. The glasses were placed on this insert and special clamps were hooked into the middle rods that held the glass lids in place. The entire insert could then be lifted into the cooking pot, after heating the jars and leaving them in the hot water for the necessary time, you took them out again and allowed the jars to cool down. After cooling, the negative pressure had built up in the jars and held the lid tight so that the clamps could be released. Later, the jars were closed with loose clips, so that the jars could be removed from the insert before they had cooled down and the insert was available again more quickly.
The use also prevented the glasses from standing directly on the bottom of the pot, as the excessive heat could have broken the glass. Today, wire or plastic insert grids are common for this purpose.
In the beginning, canning pots were often made of galvanized sheet metal, later they were usually enamelled because they could also be used as cooking pots (e.g. for soups). Today pots made of stainless steel are also available. In the early days, smaller cooking pots that could only hold one or two glasses were also widespread. Since at that time boiling was the only safe way to preserve food, leftover food scraps were also boiled down and, because of the smaller quantities, such smaller boiling pots were used for this.
In addition to the cooking pots for use on the stove, pots with built-in electric heating have also been manufactured since the 1930s, which are connected to a socket and can therefore also be used outside the kitchen. The models available today have a thermostat with which the temperature of the water bath can be precisely regulated so that a separate thermometer is no longer necessary, some also have a timer that switches the device off after the set wake-up time has elapsed.
Some of these devices, known as automatic boilers, are also provided with a tap through which the water can be drained off so that it is not necessary to lift the heavy pot to empty it. These models are also suitable for warming drinks, the drink can then be easily tapped. Some manufacturers also offer inserts for canning machines that can be used as steam juicers .