Now that the ripened fruits and vegetables have been harvested, we can enjoy the fresh garden flavours. Time has come to think about preserving fruits and vegetables for the winter so that we can treat ourselves to home-grown delicacies for a longer while. If you have not yet managed to make your favourite jam or pickles, we encourage you to consider the recommendations of the Elektrum Energy Efficiency Centre about the ways to prepare preserves for the winter more easily and consuming less energy resources.

Preparatory work

Before washing fruits, vegetables and jars, make sure that the mixer tap is equipped with an aerator – a water-saving device. An aerator mixes water with air, giving the feeling that the water flow is bigger, while reducing water consumption by 50%. If the flowing water is white and foamy, it means that the mixer tap is already equipped with an aerator.

If there is a dishwasher in your dwelling, use it to prepare the jars. The drying process in a dishwasher is carried out at high temperatures, making the jars sterilised. This way, you will consume considerably less water, as a modern dishwasher uses only 6 to 8 litres of water per cycle. By contrast, this amount of water flows out of a tap in less than a minute.

However, if there is no such option, wash the jars in the hottest water possible and remember not to waste the water by adjusting its flow during washing. Keep in mind that dishwashing detergents can only be completely rinsed with cold water. When the jars are thoroughly washed and dried, they can be sterilised in an oven at 150 °C for 15 minutes.

Please note! Do not re-use canning lids. A used lid is a used lid: the rubberised elastic plastic seal inside is meant for sealing up the jar, and if it is even slightly damaged, the effort invested in making the preserves may well be wasted, as the preserved products will start to deteriorate.

Once the products and jars are prepared, the cooking process can start. To use energy more efficiently, choose a pot with a thick bottom and an appropriate size for the burner. The diameter of the pot base should completely cover the burner or be bigger than that in order not to heat up the pot handles and to prevent heat loss.

Always use pot lids, preferably those made of glass, to keep the heat in the cookware and cook faster. It will reduce the energy consumption required for preparing the preserves.

Making jam

Berries, especially red ones, contain valuable antioxidants, protecting the body from harmful free radicals, which contribute to both development of diseases and aging. However, at high temperatures, these biologically active compounds decompose or get destroyed, and the amount of other healthy substances, including vitamin C, also diminishes. The loss of antioxidants is indicated by the colour of the jam: the darker and more brownish it becomes, the less valuable substances is left. To make the jam healthy, it is recommended to boil it for a short time, skim the foam and remove it from heat.

Jam sugar is suitable for this purpose, as jam needs to be boiled for no more than 5 minutes after adding it, whereas cooking with regular sugar takes at least 10 minutes. Moreover, nutrition scientists have discovered that during a long period of boiling, the sugar that is added to jam decomposes, producing the unhealthy substance hydroxymethylfurfural, which has a carcinogenic effect.

Pasteurising canned food

To pasteurise stewed fruit drinks (kompots) and other pickled preserves, it is more efficient to use a large 20 or 25 litre pot, where you can simultaneously put several jars, instead of using several small pots and therefore heating several burners.

To use energy efficiently, begin the pasteurisation process by switching on the cooking top to maximum temperature until the water starts to boil and then reduce the stove’s heating intensity to the desired water temperature.

Try something unusual

Plum and chestnut jam

Ingredients: red plums: 1 kg, chestnuts: 200 g, sugar: 500 g, cardamom: 5 g, ½ lime zest.

Preparation: Slit the plums and blanch them in boiling water for 30-45 seconds, peel them and remove the stone. Cut 300 g of the plums into cubes and slice the rest finely. Boil the chestnuts until they are ready, peel them and cut them into cubes. Stew the sliced plums with sugar for about 25-30 minutes and then blend them. Add the plums cut into cubes, cardamom, lime zest and chestnuts to the mass and stew for another 5 minutes.