Is the practice of reusing glass bottles safe to use for canning? Can you reuse store bought jars for canning?
Canning is a great way to save your garden produce. It’s made to be shelf stable, so you can store it on the pantry shelf, saving you plenty of freezer or fridge space.
Even the Experts Don’t Agree
There are lots of jars to be found at thrift stores, yard sales and more to get you started. There are jars from spaghetti sauce, peanut butter and even mayo that are just waiting to be filled with garden goodness. But, is the practice of reusing glass bottles safe to use for canning? Can you reuse store bought jars for canning? That depends on which camp you belong. Some say “absolutely not,” and some say “sure, why not, reusing jars is completely safe.”
According to the National Center For Home Canning,
Most commercial pint- and quart-size mayonnaise or salad dressing jars may be used with new two-piece lids for canning acid foods. However, you should expect more seal failures and jar breakage. (emphasis mine) These jars have a narrower sealing surface and are tempered less than Mason jars, and may be weakened by repeated contact with metal spoons or knives used in dispensing mayonnaise or salad dressing. Seemingly insignificant scratches in glass may cause cracking and breakage while processing jars in a canner. Mayonnaise-type jars are not recommended for use with foods to be processed in a pressure canner because of excessive jar breakage. Other commercial jars with mouths that cannot be sealed with two-piece canning lids are not recommended for use in canning any food at home.
It’s Okay to Reuse Some Jars
So, you CAN reuse some spaghetti sauce jars, some mayo jars or peanut butter jars with little issue. Best practice is to make sure they are very clean and sterilized. The lid and band will need to fit snugly on the top of the jar as well. If you notice any cracks, toss the jar and do not reuse. Small cracks can cause the jar to become weaker and break. They just are not suitable for pressure canning. During World War Two, the USDA actually encouraged people to reuse jars from store-bought (spaghetti sauce, mayo etc.) to home can garden produce with. This was due to the wartime shortage of glass. This was a common practice for many households for years.
When Old Canning Jars are Not Safe
Are there times when the recycled mayo, spaghetti sauce, or peanut butter jars are NOT safe? Sure. The quart sized mayo jars that many say “My Grandma reused these with no problems” are not designed to withstand the heating and reheating that comes with home canning food safely. They also have a more narrow sealing surface, and the lid may not properly seal out air, bacteria and such. An improper seal will cause loss of food, and possible bacteria build up that you DON’T want.
The advice for reusing store bought jars is actually no longer USDA recommended for home canning, and Nancy Hudson, a former extension agent in Greene County, Ohio, explained the reason for the recommendation as far back as 1986:
As of 1987, USDA will be recommending the use of one way jars such as instant coffee or mayonnaise jars to be used in a hot water bath canner only if the family has no other alternative However, these jars will not seal with the zinc lids and rubber rings…. With one way jars, the glass is thinner and will take a heat shock of only 75 F degrees. If the jar is at room temperature (70 F degrees) and the food is at 145 F degrees, you will have no breakage. However, with a one way jar at room temperature and the food at 190 F degrees, the jar will break.”
Never use commercial jars such as mayonnaise and pickle jars for home canning. These jars are not very resistant to temperature extremes; they break easily. Also, lids may not seal on these jars because their sealing edge is rounded rather than flat. Finally, the neck of the jar may be so short that the screw band will not hold the lid firmly in place during processing.
What does this mean?
Do you need to throw away all your old jars that are from store bought products? I have a bunch of old mayo style quart jars that my home canned peaches look simply lovely in. Many people like to reuse glass jars for canning simply for lifestyle choices. Some are doing it because of limited funds to purchase the “real” canning jars. As always, you are free to make your own choice here. When in doubt about the jar, err on the side of caution and safety. Reusing glass jars for food storage such as oats, rice, dried beans may be a much better idea for some.
Rules to Remember before Reusing Glass Jars
If you choose to reuse jars from store-bought products, and wonder if it’s really safe, just remember:
- No commercial product maker is going to endorse their jars for re-use in home canning, ever. There are too many risks with broken jars and loss of food for them to suggest it.
- Be aware that there is a higher risk of breakage of reused jars.
- Most experts advise to avoid such jars in pressure canning, if possible.
- The rims of reused jars are commonly just a bit thinner than rims of certified Mason jars, making it harder for the rubber gaskets on the undersides of the lids to get something to grip onto and make a strong, lasting seal.
- Before you re-use a jar for the first time, test to make sure that your two-piece lids fit first before filling it up, and verify that the gasket sealing compound fits out to the edges of the rim of the jar.
Do you reuse your store bought glass jars for canning or do you avoid them completely? Be sure to pin this for later!