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Do Brand New Mason Jars Need to Be Washed?

New to the Mason jar world? Read our practical guide on whether brand new Mason jars need to be washed.

Mason jars are a true blessing in the kitchen. Their uses are virtually unlimited, ranging from canning meats, fruits, and vegetables to storing dried pasta and spices. They are also a staple in candle making, and some like to use them as drinking glasses.

Whether you’re a home caner or you simply dig the look of mason jars for drinking glasses, you’ve probably noticed a shortage of them in stores as of late. Supply chain issues mean that, these days (especially during canning season), finding mason jars in stores feels more like a treasure hunt than a shopping trip.

On the rare occasion that mason jars are available on store shelves, those needing them for canning and other home projects will often stock up. If you’re one of them—and you’re lucky enough to find them when they are “in season” and bring them home—do you need to wash them before you can use them?

The short answer is yes, especially if you are going to use the mason jars for canning. When you bring the jars home, wash them before using them for the first time. This is an important step because you don’t know how the jars were handled before they got to your home.

According to Filmore Container, a producer of glass jars and other canning supplies, jars arrive at their facility in cardboard cases. The jars aren’t sterilized before they leave the manufacturing plant and the packaging is rarely sealed, meaning that dirt and debris can end up on the jars themselves.

Even though the jars are brand new, nobody wants to use a dirty dish. Washing your mason jars before their first use will eliminate any dust or bacteria they may have picked up in the time between production and making it onto your shelves.

How Do I Wash My Mason Jars?

If you have a dishwasher, you can clean your new canning jars on the Sanitize cycle to eliminate harmful bacteria and dirt. The cycle, which uses hot water for longer, eliminates 99.9% of bacteria on the jars and effectively prepares them for their first use.

If you’re about to use the mason jars for canning, loading them in the dishwasher has a second useful function: it keeps the jars nice and warm until you’re ready to use them. Most canning recipes call for the use of warm jars. By keeping the jars warm in the dishwasher until you’re ready to use them, you accomplish two tasks at once.

Another way to prepare brand new mason jars for canning is to put them in a hot water bath. Submerging the jars in a pot of water and bringing it to a boil for 10 minutes will effectively sterilize the jars and prepare them for first use.

Can I Reuse My Canning Jars?

One of the greatest features of mason jars is their ability to be used over and over again. As long as the jars are treated properly, they can last for years to come.

For starters, make sure your mason jars stay in good shape by washing them after each use. Running them through the dishwasher or washing them by hand will help keep them from getting rusty. If you are canning with them, adding a tablespoon or two of vinegar to the canning water will help protect them from discoloration during the canning.

Another way to ensure a long life for your mason jars is to use safe handling procedures. For example, the National Center for Home Food Preservation advises never placing canning jars in the oven. These types of jars are not designed to withstand the dry heat of the oven, so they can break when.

Can I Freeze My Mason Jars?

Mason jars can be used to freeze both liquids and canned foods as long as you follow recommended guidelines. Just as mason jars aren’t meant to withstand the dry heat of the oven, some mason jars aren’t meant to withstand the ice-cold temperatures in the freezer.

The safest way to freeze mason jars is to buy dual-purpose jars that are designed for both canning and freezing. These jars are designed to withstand a wide range of temperatures, so you can safely freeze them without having to worry about them breaking. 

Some standard mason jars can also be used in the freezer as long as they are treated correctly. Mason jars have a “freeze fill line” just below the threads on the jar. A mason jar can safely be filled up to this line with contents for freezing. If they are filled beyond this point, you risk the jars cracking as the contents expand when they freeze.

Freezing Mason Jars

When freezing mason jars, it’s also important to consider their handling before and after they go in the freezer. The jars aren’t meant to withstand sudden temperature changes, so it’s necessary to reduce as much stress on the jars as possible. 

When filling the jars with hot liquids, let them come to room temperature or let them cool in the fridge before placing them in the freezer. When taking them out of the freezer, let them thaw in the fridge overnight. Doing these things will help the jars change temperature gradually to help keep them from breaking. 

Final Thoughts

Even though they can be hard to find, mason jars are a worthwhile addition to any kitchen. They are instrumental in preserving garden veggies, fruits, and meat. They also work great as drinking glasses or craft projects.

If you’re looking to put up a summer’s worth of hard work in the garden, or just want to add some farmhouse flair to your drinkware, mason jars are a great choice.

Before you head out to the store to see if you can find some of these valuable jars, keep these helpful tips in mind. When properly handled, mason jars are a great investment that can last for generations to come.