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How to pasteurize and vacuum preserve

Pasteurize 3

Following several articles by Thermorecetas, especially from the publication of the recipe for fruit jars for children Ascen, several questions arose about how vacuum pack preserves. For this reason, I have thought that publishing this post could be useful for all of you who like to cook and preserve jams, homemade sauces, baby food, etc.

There are two types of ways of preserving under vacuum: boiling the jars in water bath (safer) and another is to leave them cool upside down (less safe -for example for baby food- and only used to pack food that has been cooked at a high temperature). Let's see both in detail.

What cans do I need?

In the first place, it is very important that the cans are suitable for canning (that is, that the lid closes perfectly and is not deformed).

We can buy them or reuse cans that we have empty at home.

They close?

If we want, we can check if they close perfectly: we fill them with water and close them. We put them upside down and leave them for about 4-6 hours on a newspaper. If when we remove them the newspaper is wet, it means that some water has escaped. In this case, that pot is useless.

Are they sterilized?

Once we have the jars that we know to close perfectly, we have two ways to sterilize the jars before using them for preserving.

  1. DISHWASHER: There are programs that get quite hot, so it's a good way to make sure the cans come out perfectly clean.
  2. BOIL THEM IN WATER: We can put a large pot with boiling water and have them for 5 minutes. It is important that we put them in the pot, then cover them with cold water and finally bring them to a boil. If we put them directly into the boiling water, they could crack due to the sudden change in temperature.

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Is it a good idea to label the cans?

Of course. Once we have preserved it, it is a fantastic idea to label the jars, since this way we know what we have kept and on what date.

How long do preserves last me?

With full guarantee, if the process has been well done, you can keep your jars for 6 months in the pantry if we are talking about canned products made from fruits, such as jams and compotes or highly acidic products (such as pickled / lemon preserves ).

** If we are talking about food for babies / children there we must be much more careful. To be totally safe, those made from vegetables must be consumed in maximum 4 days and keep them in the fridge.

Can I use them as a gift?

It is a good idea to take the opportunity to give homemade jams, for example, or fruits in syrup. So we can put our jars with their labels, a nice decoration (with a cloth and a rubber that covers the lid) and put everything in a box or basket to give away.


This is the safest system to make a canning, that is why I recommend that you use if we are conserving baby food or baby food for children. In addition, the advantage is that it can be used to pack food that we have cold or hot.

  1. Must fill the cans to the top, leaving 1 cm (if the bottle is more than 200ml) or 0,5cm (if the bottle is less than 200ml) to the top. We close well.
  2. We take a large pot, put a kitchen rag inside to "pad" the bottom and sides of the pot.
  3. We put the boats inside They are separated from each other and we are putting the peaks and the folds of the cloth between the cans so that when they boil they do not collide with each other.
  4. We cover with cold water, so that they are covered by a finger of water.
  5. We put boil during 30 minutes. We put out the fire.
  6. We leave cool the boats in the water.
  7. When it is at room temperature, the we take out and we dry them.
  8. We check that the center of the lid is sunken and that if we press it does not "click". If any cover "clicks", the vacuum is not well done. We repeat the operation or refrigerate and consume in the next 4 days.

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This system is very useful and fast, but it only works if what we are going to pack has been cooked at varoma temperature because you have to pour the boiling content into the jars. For example, it is perfect for canning jams or homemade tomato sauce.

  1. We place a spoon or metal knife inside the jar (this will absorb part of the heat and prevent the glass of the jar from cracking).
  2. We cast the content boiling directly inside the boat.
  3. We fill the cans butt, "flush", that is, there is no gap between the content and the lid.
  4. We close strong.
  5. We give you the return to the pot and let it cool in that position.
  6. When they have cooled and they are at room temperature we check that the center of the lid is sunk and that if we press it does not do "click". If any cover "clicks", the vacuum is not well done. We repeat the operation or refrigerate and consume in the next 4 days.

Discover other recipes of: Tricks

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  1.   Dew said

    My question is. To make the baby food in a bain-marie, do I have to let them cool or can I put them in the hot pot?

    1.    Ascen Jimenez said

      Hello Rocio!
      It is better to put them in the hot pot.
      A hug!

  2.   Sara said

    Can you also add meat or fish?

  3.   lorrainecm said

    But if they only last 4 days in the fridge (I say baby ones), why are you going to do all this? leave them directly there when you finish cooking and instead of 4 you give them to the 3 for sure the food is still good .. I think it's making life difficult to have them one more day ...