How to sterilize jars


When you try to prepare jams, preserves or sauces at home, one of the important and essential steps to follow is undoubtedly the sterilization of glass jars. Sterilizing your jars is a simple and at the same time delicate and necessary operation allowing us to store our preparations safely, protected from bacterial contamination and for a long time, keeping them intact, healthy and genuine.

Which jars to use?

Previously used glass jars, put aside and stored in perfect condition will do just fine. However, if you are not used to recycling jars, the best thing is to buy new ones. This is also the safest choice as we will have brand new jars, perfectly clean and combined with ad hoc caps.

You can find the glass jars online or in any well-stocked supermarket or housewares store, just remember to buy the jars together with the caps as they are often sold separately.

As concerned the size of the jars, it depends on what type of preparation they will contain. For recipes such as tomato sauce, we recommend 500 ml glass jars as a maximum capacity; if, on the other hand, you plan to prepare jams, preserves or chutneys, you can use jars with a capacity of 125 ml.

sterilize jars

Why is it important to sterilize jars? What are the risks?

Sterilizing glass jars is a fundamental process in the preparation of jams and preserves. The procedure ensures the elimination of microorganisms living both in the ingredients used and in the air which, would remain inside the ja, if no sterilization or vacuum packing is performed. By sterilizing the glass jars you avoid a possible contamination of the preparations, which may represent a serious health problem.

In order to sterilize glass jars we can use different methods, let’s see some of them together.

Sterilizing jars in the oven

Turn on the oven and bring it to 120° C, place a sheet of baking paper on the grill. Then arrange both jars and lids, making sure they don’t touch each other. Close the oven and leave them inside for at least 20 minutes. After this time, remove the jars from the oven with the help of pot holders so as not to burn yourself and proceed immediately to fill them with hot jam, then seal them hermetically.

Sterilizing jars in the oven


Sterilizing jars in a pan

Sterilizing glass jars in pots is undoubtedly the most common and most used method. First of all place the jars inside a large saucepan with high sides, then fill the saucepan with cold water and place it on the heat until it comes to a boil. After the first 10 minutes of boiling, put the lids in the pot and wait 10 more minutes, for a total of 20 minutes. Remove the jars from the pot and let them dry and cool completely upside down on a cloth.

Sterilizing jars in  the microwaves

This is the method that will save you the most time! In fact, it only takes a few minutes to sterilize the jars in the microwave. Here’s how to proceed: add water inside the jars, up to almost half of the jar. Turn the microwave on and when the water boils, turn it off. Remove the jars, empty them and let them dry upside down on a clean cloth. Warning: Unfortunately, this method cannot be used with metal lids.

Sterilizing jars in the dishwhaser

The dishwasher method is one of the easiest ones for sterilizing jars. The procedure is very simple: place the jars and lids in the dishwasher and start a high temperature washing program. Once finished, remove everything and let it dry on a cloth and then use the jars as soon as they have cooled down.


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