How to sterilize jars

How to sterilize jars

If you want to prepare tasty homemade preserves or save food for a long time, you cannot avoid a fundamental step: sterilize the jars. This procedure is essential to prevent dangerous microorganisms from growing in food, as well as to make them last much longer.

For this reason, in RecipesFree we show you how to sterilize jars through the most traditional methods. We will also give you an express trick to make the process quicker and easier. There will be no more excuses, now you can fill the cupboard of your culinary creations without worrying about them getting damaged very quickly, nothing like home made!

How sterilized canning jars

You already know that if you want to preserve any food properly, the first thing you should do is sterilize the jars. This process is very simple, although you must take care of the details to ensure a good end result free of microorganisms that can damage your food.


  • Tweezers or pliers. In culinary stores they sell special tongs to handle jars, but you can also use common ones.
  • 500 ml or 200 ml reinforced tempered glass jar.
  • A natural fiber towel (very clean).
  • A deep casserole.


  1. Check that the jars are in perfect condition. They cannot have any breaks or cracks, and the caps must screw on well. In addition, they must be seen without traces of rust or scratches.
  2. To certify the condition of the lids, fill the jars with water, close them and put them on their sides. If they leak, replace the caps with others. If you use used jars, remove the labels or glue.
  3. Wash your hands very well with warm soapy water, thus completely removing any contaminants. Perform this procedure for at least 20 seconds.
  4. Scrupulously clean the jars. Use a brush, warm soapy water. Both lids and jars must be impeccable.
  5. Place a folded towel inside a deep pot. It should cover the inner walls of the pot, this way you will avoid that when the water starts the boiling process, the jars will hit and break. Additionally, you can put a towel between them.
  6. Insert the cans vertically and face up, put the lids around. Pour the water until they are completely covered, at least 2.5 cm above the containers. If you don't have a very deep casserole, you can also put them horizontally. Let them boil at least 10-15 minutes and maximum 30-45 minutes, over high heat, with the pot lid on. After the time has passed, let them temper inside the pot.
  7. Remove them from the pot with a tweezer Place them face down on a clean towel, absorbent paper, or on a pan with a grid (this is the best option). Let them drain very well before storing food.
  8. Preheat oven to 120 ° C or lower temperature for 5 minutes. Then arrange the jars on a clean tray or cloth. Put the tray in the oven, wait 3 minutes and turn off. Take out the jars just when you go to pack the food.
  9. Spray alcohol into the jars. Although it is not an essential step, some people do it. Use a solution of 96-degree ethyl alcohol (700 cc) and filtered or mineral water (300 cc). Apply it with a spray bottle inside the lid and the bottle. Wait two minutes for the alcohol to evaporate completely and fill the jars with the canning.

Discover How to make homemade preserves of all kinds by entering the link.

Advice: All the elements you use must be impeccable: towel, clothespins, tray, etc.

How to sterilize jars - How to sterilize canning jars

How to sterilize glass jars without boiling

Although it is always preferable to choose the traditional method of boiling the jars, there are also some quite efficient express methods. However, it is important to remember that before using any method you should:

  • Wash your hands very well.
  • Clean the jars carefully.
  • Check the condition of the jars and make sure they are resistant to high temperatures.
  • Drain the jars upside down on a clean towel after sterilizing them.
  • Finish drying them very well (preferably using the oven).
  • Spray them with a solution of ethyl alcohol and water (2 minutes before using them).

With that said, we invite you to review the following quick flask sterilization methods:

  • Dishwasher. It can serve you if it reaches high temperatures above 110 ° C. Place only the cans (do not put anything else in the dishwasher, or the lids). Dip the lids in boiling water for a few minutes. Once sterilized, both the jars and lids, dry them very well.
  • Steam oven. Some ovens have a sterilization program, which is used to prepare jars of jam and preserves, both empty and full.
  • Conventional oven. You can use any common oven to sterilize jars. Preheat oven to 110 ° C while arranging lids and jars on a cookie sheet. Put the tray in the oven and wait 20 minutes before turning it off. Leave the jars there until packaging time.
  • In the microwave. Fill the jars halfway with water. Place them in the microwave, separated from each other. Do it two by two and without the covers (the metal damages the microwave). Program 3 minutes or until it boils, using maximum power. Once the time is up, leave them inside until they cool. Carefully remove the jars from the microwave using a clean towel or clean kitchenware. Discard the remaining water (if any) and complete drying in the oven, at minimum temperature and with the door open. Lastly, it disinfects the lids by immersing them in boiling water.
  • Thermomix. Pour 600 ml of water and put the basket inside the glass. Put the lids of the jars inside. Put the Varoma container in position and place the glass jars upside down. Program 30 minutes / Varoma temperature / speed 1. Once sterilized, they will be ready to use.

If you can't sterilize the jars, we invite you to visit more Food Preservation Methods so they last longer and are better preserved.

Advice: Never touch the jars inside or on the rim after sterilizing.

How to sterilize jars with jam

We have already seen how the jars are sterilized alone, without content; now we will show you how to sterilize jars with the canned food inside, in this case of jam. It is interesting to mention that when we sterilize a jar with some preserves, the process serves two things: pasteurization and creating the vacuum.

Remember, before this process you should always sterilize the jars previously, using some of the techniques mentioned above.


  • Funnel (uses special canning funnels, the mouth of which is specially designed to fit precisely into the jar)
  • Plastic soup ladle (will serve to deposit the canned food in the jar)
  • Tweezers or pliers.
  • 500 ml or 200 ml jar.
  • A natural fiber towel (neat)
  • A deep casserole


  1. Place a folded towel on the bottom from a casserole. The cloth should also cover the sides. There are also special racks that are placed at the bottom of the pot, or you can wrap each jar with a towel. Choose a large, deep casserole.
  2. Put the jars upright. Once filled with the canning, put the jars with the lid upwards without colliding between them. You could also put a towel between them.
  3. Cover the jars completely with water and cover the casserole. When filling the pot with water, remember to leave a couple of centimeters above the lids of the jars (5 centimeters).
  4. Heats the jars for 20-30 minutes from the start of the first boil.
  5. Let the jars cool in the saucepan. When the jars are warm, you can remove them with a tongs. Dry them and place them face down on a clean towel, wire rack, or paper towels until they cool completely. Wait 24 hours before handling the jars, as they must be completely cold before storing them.
  6. Check if the vacuum was made. Press with your fingers on the lid trying to sink it, if you can't, you have a successful process. Another way to make sure is to see if the lid is arched (like a dent); if so, at some point it will return to its place and produce a sound, similar to a "clap", confirming that the vacuum was made. If the bottle does not have any of these characteristics, open it and consume it immediately.
  7. If you want an even safer, but longer process, tinalize the preparation. The process is the same as in sterilization, but the standard cooking time is 45 minutes. Then let it cool for 24 hours at room temperature and repeat the cooking process. The exposure temperature should be around 100 ° C.
  8. Label the jars. Write down the date of packaging and the type of canning.
  9. Store the preserve in a clean, dry and dark place. If the process was successful and you save it properly, it should last at least 1 year.

Advice: The jam you must pack it still hot.

How to sterilize jars - How to sterilize jars with jam

If you liked the article How to sterilize jars, we suggest you enter our Cheats and techniques category.

1 Compartir