I remember my grandmother spending most of the summer and the early fall making preserves and pickles.
To me as a child, it made no sense that someone would spend all that time cooking in the summer heat when you can buy it all at the store.
But one day, she was gone and, to add to the immense heartbreak, I had to buy all that stuff at the store.
Getting into canning helped me stay connected with my grandma. However, I’ve soon realized that I have been there during the fun part – mostly cooking and eating. I did have her recipe book to guide through that, but she did not write down anything about the “boring” stuff. Let’s just say that I’ve learned the hard way what happens if you don’t sterilize the jars properly.
Here are a few methods that worked for me over the years when I had to sterilize mason jars. Find the one that works best for you because trust me, you don’t want to spend time making the most amazing jam to open the jar ad find the most amazing mold.
Just remember not all recipes calls for the jars to be sterilized so remember to check your recipe.
How to sterilize mason jars on the stove
I recommend doing this or in the oven
This is the method that my grandma used to use. All you need is a large pot and a healthy awareness of boiling water.
Start by washing your hands – you want to keep your hands clean throughout the whole canning process.
Wash your jars and lids thoroughly (if you reuse old lids). Break out that toothbrush so you can give a good scrub to every nook and cranny. If there are old leftovers in the jars.
Choose a pot that is big enough for your jar to fit and fill it with enough water to cover the jar. You want to use a pot that is big enough so it’s 3/4 full at the most. Bring the water to the boil.
Using a pair of tongs, place the jar into the water and boil for 10 minutes. Boiling water will eliminate any bacteria and remove any remaining impurities, giving you optimum sterilization.
You might have to extend your timer depending on your altitude. Stick to said times for altitudes up to 1,000 ft and after that, for every 1,000 ft add another minute. For example, if 800 ft requires 10 minutes, 1800 will need 11 minutes, and 2800 will need 12, and so on.
Use the tongs to remove the jar from the water, and place it on a clean towel. When it’s cool enough to handle, wipe the jar with the towel and then leave to air dry completely.
A quick note – towels you are using should either come from a hot water load or should be boiled as well to remove bacteria. If they are coming out of your washing machine, skip the fabric softener because it can promote the growth of mold. The steam cycle of your dryer can help kill off a few more beasties.
Remember that you have a pot full of boiling water on the stove! Allow it to cool before you dispose of it.
How to sterilize mason jars in the oven
If you don’t want to mess with a pot of boiling water, you can sterilize your jars in the oven.
I recommend doing this or on the stove listed above
Start by washing your jars like previously. Preheat your oven to 210° F (140° C) and line a baking tray with baking parchment or a silicone baking sheet.
Place the jars in the pan right side up and heat them for 15 to 20 minutes. Let them cool down completely before use.
This method is not suitable for lids.
If you have a combination steam oven, you can set your steam to high and leave the jars in for 10 minutes. If you can run a heater with that steam, it’s even better.
How to sterilize mason jars in the microwave
Your microwave is great ad doing the job quickly because it uses both the heat and the radiation to kill off all bacteria.
Scrub your jar clean and rinse it thoroughly. Place the wet jar directly on the glass plate. Microwave on high (1000w) for 60 seconds. If you see some steamy action, you’ve done a good job.
This method is not suitable for lids and flip-top jars because of the metal.
Personally, I skip this method for anything that needs to live in the pantry for months and just use it for things that will be devoured quickly. There is no data that I can find that says it’s inferior to others, but I don’t trust it as much as the oven or the stovetop method. Just my two cents.
How to sterilize mason jars in the dishwasher
There is a lot of misinformation online about this topic. The truth is that the water in most home dishwashers goes only up to 140° F, while you need 210° F to kill bacteria.
Consult your owners manual or contact the manufacturer to see if your dishwasher can go that high. If you are lucky and it does, run your jars on the rinse cycle for as many times as you need to get them in contact with hot water for at least 10 minutes.
If you have a steam dishwasher, check with the manufacturer is the steam cycle can be used for disinfection and sterilization.
How to sterilize mason jars in the pressure canner/cooker
If you have a pressure canner or a large pressure cooker, you can get them to do the job. If you are on a market for a pressure cooker, you can check out peeps have to say about them in the video below.
Start by cleaning your jars. Fill the canner or the cooker with some boiled water. Just 1 or 2 inches of water is enough. Place your jars right side up and close the lid. You can place as many jars as the pot can fit. Ideally, your jars should not be more than 3/4 height of your pot.
Place your pot on the stove and bring it to pressure. The temperature inside will rise above the boiling point of water and that will kill off all the nasties.
Let the jars cook at high pressure for ten minutes and then either choose to release the pressure quickly or slowly. For the slow-release, take the pot off the hob and leave it be. For a quick release, either put the pot under running water to cool it quickly, or use a spoon to press on the pressure valve to release the steam.
Some electric models come with a canning set or an optional canning kit you can buy. Check those guys out because they have a nifty rack that can make jar removal as safe and painless as possible.
How to sterilize mason jar with steam
I don’t recommend doing this, do to the risk of steam burns.
Using steam is great if you have one of those in pot steaming baskets
With the basket in the pot, place the lid and boil water until the steam forms. Place the jars upside down and let them steam for 8 to 10 minutes. Take the basket out of the pot and remove the jars. Dry them thoroughly.
If you have a good steam cleaner, you can use the smallest nozzle attachment in the kit. Just remember to wear oven gloves to protect yourself from the heat, and to clean and sterilize the nozzle itself before getting it anywhere near your jars. It will get a bit irritating though because you have to expose them to the steam for at least 10 minutes.
How to sterilize mason jars with bleaching powder
I don’t recommend doing this, it can add a chemical aftertaste.
Bleaching powder or calcium hypochlorite is known for its bleaching as well as disinfectant properties. It’s the main active ingredient of commercial bleaching products and is used in water purification and disinfecting pools.
You will easily find it at many home improvement stores or online.
Make a solution of one teaspoon bleaching powder and one-quart water. Scale the recipe as needed.
Use a pair of tongs to place the jars and lids into the solution, and leave them in there for 20 minutes. Make sure to avoid contact with skin, and especially the eyes.
Once the 20 minutes have passed, take out the jars with tongs again, and then rinse them thoroughly with boiled water. Make sure there is no solution left on them because it can cause gastric issues. It can also react with the food you are trying to preserve and change their taste and appearance.
Wipe the jars dry before using them.
How to sterilize mason jars with antibacterial sterilization tablets
I don’t recommend doing this, it can add a chemical aftertaste.
Antibacterial sterilization tablets are often made from hypochlorites. They may be regarded as the salts of hypochlorous acid and are highly effective at exterminating all forms of microbes and bacteria, like the ones that cause mold.
You can find them at big box stores, kitchen supply stores, pharmacies, and online.
Clean the jar thoroughly as usual. Dissolve the tablets per manufacturer’s instructions. You will need about a quart of solution for two small to medium-sized jars.
Submerge the jars and lids completely and leave them for 10 to 15 minutes. The instruction on the package will tell you what is the optimal time for that product. Rinse the jars completely with boiling hot water.
This method is highly effective, but it can add a chemical aftertaste to your food. It would be best to use for something with a strong flavor like chutneys and pickles, and skip it for jams and marmalade.
Hot to sterilize mason jars with alcohol
Another one where there is a lot of misinformation. To put it simply, you can’t.
You can use 70-96% or rubbing alcohol to disinfect any container that is supposed to store your food, but in preserving, it’s useless. You can use it as an extra step after washing, but it’s better to pick another method for sterilizing.
How to sterilize mason jars with UV light
This one is not realistic for most homes, but I am in love with it.
Some time ago, I’ve splurged on a fancy food dehydrator with a UV light sterilization setting. I got it from China and, with the shipping and customs, it ended up costing just a tad bit more than the leading brand’s higher-end model.
Was the price worth it? Bet your marmalade it did.
The only downside is that it’s not that great with bigger jars. But for the smaller ones and when you feel lazy, it’s perfect.
For a slightly more affordable version, you can check out baby bottle sterilizers.
How to sterilize mason jars lids
This is where it gets a bit tricky.
For plain metal lids, you can treat them the same way as your jars. Rubber seals, on the other hand, can be a little problematic.
If your heart is set on the flip-top mason jars, make sure to pick up the seals that can stand high heat. You will need to boil them for a few minutes to sterilize them, as well as expose them to more heat during the canning itself.
Remember to have as little contact with the sterilized lids as possible. Pick them up on the side or with a pair of sterilized tongs.
And always, always, always use new lids and sealing gaskets. I advise buying them in bilk so that you can save money.
An extra step for dry food storage
Just a quick note on canning dry goods. While you can use your boiled or steamed cans straight away with your apple butter or kimchi, it’s not the case for your beef jerky or lemon slices. Even a little bit of moisture can mess with your product.
Either choose a “dry” method (like the oven method) or give the jars an extra minute to dry properly before storing your dehydrated food. If you’ll eat it pretty soon it doesn’t matter that much as if you plan to dip into your stash months or years down the line.
And yes, I said years. If canned properly, dry foods can be stored for up to 15+ years.