Keeping fruits and vegetables for this winter, good idea! Here are some basics to succeed in this operation.
What jars should I use?
In glass, which can be recognized by their orange rubber washer, Le Parfait type. They have the advantage of being very inexpensive and “indestructible”, provided you do not drop them on the ground! Ecolos, they can be reused at will. Buy them in several sizes, so you can adapt the models to the recipes. Reserve those of 20 or 35 cl for small pâtés, fish rillettes, tapenades and spreads. In those of 50 cl, keep the tomato sauce, the ratatouille or even the soup for two people. In the larger one-litre jars, store your ratatouilles for the whole family, your fruits in syrup or your canned asparagus. Finally, for the jam, prefer real 30 cl jam jars.
For successful preserves, hygiene must be impeccable! First wash the jars (new or not) in hot water with dishwashing liquid before placing them, upside down, on a clean cloth to dry. For added safety, you can also sterilize empty jars. This operation is quite simple. Simply plunge them, open, into a Dutch oven filled with cold water. A large casserole is also perfect. You just have to make sure that they are completely submerged in water and that they stand perfectly upright. The trick? Pack them well against each other so that they do not move once the water comes to a boil. Leave everything on the heat for ten minutes after the start of boiling. Then remove them with pliers and put them to dry, turned over, on a clean tea towel. Be sure to renew the rubber seals after each use.
Conservation will be optimal if you use a jar size adapted to the recipe. In general, there is a level of filling materialized by a line 2 cm from the top of the jar. Carefully fill to this level for sterilization to work. If you go over, the preparation may well overflow at some point. And if you do not fill enough, the risk of seeing the product spoil is greater, because you will trap more air when closing…
After filling the jars, close them and place them in a large Dutch oven. Cover them completely with water (go up to at least 2.5 cm above the lid). Boil at 100°C to kill bacteria. Turn off the heat and wait five minutes before removing the jars.
Sterilization at 100 or 120°C, what is the difference?
The actual sterilization takes place between 116 and 140°C. However, in a Dutch oven, water boils at 100°C and it is impossible to go beyond that. This is why we talk about sterilization at 100°C when we talk about the preservation method inherited from our grandmothers. It is also called (just to get a bit lost!) “sterilizing pasteurization”.
For true sterilization, you need a pressure device such as an autoclave, which rises to 121°C (not to be confused with the sterilizer, whose temperature does not exceed 100°C). If this device is common in the United States, it is less the case in Europe.
Sterilization at 100°C is considered by all specialists to be sufficient to store jars at room temperature.
When done, let your jars cool to room temperature, then try opening them one at a time. If the sterilization worked, you will not be able to unlock them and the seal will remain in place, even when you open the iron fitting or remove the clips. In the opposite case, either you did not wait long enough, or the water was not hot enough, or the jar was too full… In short, start the whole operation again by changing the rubber before starting a new one. sterilization.
And is pasteurizing easy?
Yes, it is an uncomplicated technique to perform at home with a simple pot of water or a thermostat sterilizer. It is often done around 80°C, which preserves the taste and nutrients of the food better than higher temperatures. Pasteurization kills “living” micro-organisms that would prevent good preservation of food, but it does not destroy the spores of micro-organisms. Your pasteurized jar must therefore be stored at low temperature so that these spores do not germinate in the can.
Can I put everything in jars?
No, do not can products that have been frozen. Place only very fresh fruits and vegetables, in season and picked when ripe, sometimes blanched. Ditto for meat and fish if you make terrines: use only very fresh ingredients! For cooked dishes, such as tomato sauce or soup, pour the boiling mixture into the pots.
The pro tip
Do not force when closing screw top jars. When the jar cools, the lid sticks to it and is difficult to open!
Check that the cover is still holding well “on its own”. If it opens, if it does not resist pulling or if it “pschiiit” when opened, it means that the can has changed state since sterilization. In question ? Bacteria that have grown, which creates gas. If in doubt, discard the contents without tasting.
Is a sterilizer essential?
Certainly, this device is easy to use with its thermostats, timer and drain valve that make our lives easier. But it is cumbersome and impractical when you have few jars to sterilize. So you can do without it, because a large pot will do the trick! You can also use your pressure cooker or… your steam oven, if you have one with a sterilization function: just place the jars vertically on the oven rack.
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