Dry pasteurization: A simpler way to preserve food at home

Pasteurization is a process in which food is subjected to thermal treatment. This allows food products to be stored longer and significantly reduces the activity of microorganisms, such as bacteria, yeast, and moulds. At home, jars are usually pasteurized using a pot of boiling water, but recently, an alternative, even simpler method has been gaining popularity.

Dry pasteurization is a preservation method using an oven. As the name suggests, this type of pasteurization does not require water; the heating elements in the device provide the temperature. But how do you go about dry pasteurization to ensure that the preserves are well preserved?

To be well-prepared for dry pasteurization, a few details need attention. First - only twist-off jars, the classic ones with a screw cap, are suitable for pasteurization in the oven. Any container with flexible rubber or rubber seals may not be suitable for such high temperatures. Secondly, jars cannot be damaged or even scratched. This is obvious to anyone who makes preserves at home. However, special attention should be paid to this before dry pasteurization in the oven. It is also worth remembering not to fill the jars with preserves to the very top. Leave about 2.5 centimetres of free space.

1. Place the prepared and tightened (you don't have to tighten the jars for dry pasteurization very much) jars with preserves on a baking sheet lined with parchment paper or a cloth. Arrange the jars so that they do not touch each other and the oven's walls. Importantly, place the jars with the lids facing up.
2. The next important issue is the pasteurization temperature. With dry pasteurization in the oven , the same method applies as with classic pasteurization in a pot. So, pasteurize cold preserves starting from cold water or in a cold oven, and hot ones from hot water and in a preheated oven.
3. If you put preserves in a hot oven, preheat the device to 120°C (no convection). On the other hand, if you pasteurize cold preserves, first put the baking sheet in the oven and then set the oven to the same temperature.
4. How do you count the pasteurization time? In a preheated oven, it is simple: about half an hour from the moment you put the baking sheet with jars inside. However, if you pasteurize from a cold oven, count 30 minutes from when the device heats up. Most modern ovens have a light that goes out when the device reaches the set temperature. The most modern ones inform about this on the display.
5. After the indicated time, leave the jars in the oven for 30 minutes with the door slightly open. When they cool down, simply tighten the lids securely and set the jars upside down for 24 hours. After this time, store the preserves in a cool, dark place.