Homemade jams. Its conservation, sterilization, pasteurization (part II)

Last week Virginia, author of Sweet&Sour , gave us an introduction to jams and preserves , explaining the differences between marmalades, preserves and jellies, and explaining how to prepare them.

But when preparing jams there is one very important thing that we must keep in mind, and that is how to do it so that they are preserved for a long time, given that we often use seasonal fruits to make jam, and thus be able to enjoy them throughout the year.

Well, today Virginia is going to talk to us about exactly that: how to sterilize jam correctly in jars, and how to vacuum pack it so that our preserves last 6 or even 12 months.

III.- CONSERVATION

The best way to preserve homemade jam is in “healthy” and properly sterilized glass jars.

The glass jar should be free of nicks or fractures and the lids should close properly. In the kitchen utensils section of our store, you will find canning jars with French closure, which also have a lid that you can completely remove, making them easy to use and clean, and to present directly to the table ( you can see them here ).

The best way to determine if a lid is sealing properly is to fill the jar with water, close it, and place it on its side. If it leaks, the lid will no longer be useful and will need to be replaced.

Once the jars have been sterilised, the best way to fill them is with the help of a special funnel for preserves , which has a mouth wide enough for the jam to be easily introduced into the jar, but narrow enough to fit into the mouth of the jar. There are also some with an adjustable neck, so that they easily adapt to the mouths of different sizes of jars.

Glass jar with French closure ; wide-neck funnel especially for preserves .

IV.- STERILIZATION OF BOTTLES

VACUUM AND PASTEURIZATION:

To sterilize the jars before filling them with jam, we can wash them in the dishwasher, which maintains high temperatures, but for greater safety I recommend the following method:
- Fill a large, thick-bottomed pot with water and place on the fire. Place the jars in, well covered by water (about 3-4 fingers deep) and with their lids loose. Use cloths to separate the base of the jars from the base of the pot and to separate them from each other, so that they do not hit each other when they are bubbling while they are boiling, as this can cause them to crack.
- From the first boil, we will count at least 10 minutes. We will let it cool inside the water to avoid sudden changes in temperature that could break the jars.
- We take it out, preferably using special tongs that exist to keep it sterilized and not burn ourselves, and let it dry upside down on a clean cloth or absorbent paper.
- We do not refill or store them in the pantry until they are completely dry.

Once filled with hot jam, we must create a vacuum to extract the air that allows the proliferation of undesirable enemies for its healthy conservation.

The quickest way is to pour the hot jam into well-dried and previously sterilised jars using a wide-mouthed funnel, filling them almost to the brim. Close the lids tightly using tongs and turn the jars upside down until they cool.
In this way we achieve a kind of vacuum that allows the preserve to be stored for 6 months. Preserves that have been vacuum-sealed in this way are best stored cold rather than at room temperature. Of course, always in a cool, dry and dark place.

Preserving set (left); Le Creuset jam jar

However, the most advisable way, if we want our jams to last longer safely, is to create a vacuum by pasteurising their contents: once our jars are filled with the preserve and hermetically sealed, we put them upright in a pot with cold water covering them by about 3-4 cm above. We put them to boil, with cloths on the base and sides separating them from each other, so that they do not hit each other.

From the moment the first boil begins, we have to wait about 20-30 minutes for small and medium-sized jars, since these jams have a high sugar content, a good preservative in itself, so the cooking time is reduced. Other preserves require up to 45 minutes of cooking for complete pasteurization.

If we use a pressure cooker to make the bain-marie, the time is reduced by half. I use my WMF Perfect pot, which has two "rings". To give you an idea, I pasteurize with just one ring.
Once the time has elapsed, turn off the heat and leave them inside the pot until they are warm enough to be removed. Remove them with the help of tongs, dry them and place them upside down until they have completely cooled.

When you turn them upside down, the lid should be slightly concave, i.e. slightly arched towards the inside of the jar. This will mean that the vacuum has been properly created.

With this system, the shelf life of the preserve is longer, 1 year, and it can be kept without refrigeration, in a cool, dry place and protected from light.

V.- LABELING AND PRESENTATION

We must label jams prepared in this way with the date of preparation so that we can always keep track of them, and if we have prepared several jars, we must indicate the number that each one makes, especially to keep track of how many we have left.

It is advisable not to use excessively large jars, otherwise, once opened, when air gets in, they tend to spoil more easily if not consumed within a certain time. In my experience, the best ones are those with a capacity of 200 ml to 500 ml .

If you are going to use the jams as a gift, I recommend putting some nice cloth or paper hats on the lid , and a nice label... or a rustic string that also looks great!

NOTES : Remember that if you are looking for inspiration to make your own homemade jams, you have several recipes that you can turn to:

- Peach jam, in the recipe for almond cake with jam

- Rhubarb and Banana Jam with Citrus

- Cherry and blueberry jam

- Green Apple Jelly

- Fig jam with Armagnac

If you are interested in making your own preserves, there is a book that may interest you: From the garden to the pantry, by Mariano Bueno.