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How to Can Food BPA-Free: Toxins in Mason Jar Canning Lids


I'm a mother, environmental scientist & former Covid contact tracer who does research on a variety of health-related topics. Copyright 2021

Many mason jar lids contain BPA, a plasticizer, which acts like estrogen in the body, disrupting normal hormone regulation.

Many mason jar lids contain BPA, a plasticizer, which acts like estrogen in the body, disrupting normal hormone regulation.

Many home canning jars contain BPA in the lining of the lid. After all the hard work of gardening and preserving your own healthy food, it's a shame to store it in a container that contaminates the food with BPA. The term BPA-free isn't necessarily better, but there are options for home canning such as using Weck jars, where BPA is avoided while also considering recommended food safety guidelines. I want to help others consider a new or different view, but always be mindful that any action taken based on these opinions is the responsibility of the reader.

Bisphenol A chemical structure.

Bisphenol A chemical structure.

Why Is BPA a Problem?

BPA, or bisphenol A, is a compound present in plastic products such as water bottles, paper receipts, and the lining of food cans and mason jar lids. As BPA leaches out of these plastic products and is consumed, it mimics estrogen in the body. Hormones are normally secreted into the bloodstream by a system of glands known as the endocrine system. The addition of hormone-mimicking compounds disrupts this regulated process and is linked to negative effects on development as well as the neurological, reproductive and immune systems.

The U.S. National Institute of Health states that animal studies show a link between exposure to BPA and disorders such as early onset of puberty, breast and uterine cancer, asthma, diabetes and cardiovascular disease.

Exposure to BPA is widespread. The Center for Disease Control found, through a study in 2003-2004, that 93% of Americans six years and older have detectable levels of BPA in their urine. Eliminating continued exposure is shown to drastically reduce the amount of BPA in the body according to a 2011 study by the Breast Cancer Fund. Minimizing BPA exposure by finding alternative choices in everyday products will reduce these effects significantly. BPA-free home canning is one step in this direction.

Is BPA-Free Better?

Now that BPA has gotten a bad rapport, BPA-free products are popping up. This is good news and bad. The bad news being that unknown chemicals may be replacing BPA in products. The general purpose of BPA is to make plastic hard and keep metal from rusting. These needs still need to be met with plastic products and metal food containers. So, what's being used? Scientists have discovered that other compounds that leach out of plastic may have an even greater effect on estrogen in the body than BPA.

It's expected that the standard wide-mouth jar brands will soon be offering BPA-free lids for their jars. My guess is that this is a marketing scheme to subdue fears of BPA without truly lessening chemical exposure from the lid. Time will tell. The best way to avoid BPA and BPA-like chemicals is to avoid plastic and metal for food storage altogether.

Notice the glass lids with rubber rings. Let's get back to our roots and get away from BPA lined metal lids.

Notice the glass lids with rubber rings. Let's get back to our roots and get away from BPA lined metal lids.

Recommended Jars for Canning

In the U.S., the National Center for Home Food Preservation recommends using mason-type wide-mouth jars for canning: Ball and Kerr mason jars are examples. This type of jar requires new lids each time they are used. This new lid makes it easier to achieve a proper seal, reducing failure rates and food spoilage. However, these jar lids contain BPA.

In Canada and Europe, glass jars with glass lids and rubber rings are the accepted choice in home canning. Weck jars are a trusted brand that's been used for about a century. With some diligence to make sure that the reusable glass lid and rubber ring meet quality specifications year after year, these jars provide a reliable seal. Replacement rubber rings are available if needed.

Weck Glass Lids and Rubber Rings—How Does It Work?

Weck brand is the example I'm using in this article since I am personally familiar with it. I have tried them and they worked beautifully. All components, including the rubber ring, are BPA-free.

The Weck glass jar and glass lid are sealed with a rubber ring between them. Metal clamps are used to hold the jar closed while processing and then they are removed. The rubber ring has a tab that sticks out on one side. After processing the food, the tab will point downward, indicating a proper seal. After storage, the seal can be checked in two ways. The tab should still be pointing downward, and upon pulling the tab to open the jar, there should be a release of air as the seal is broken.

Does the Food Come in Contact With Lids During Canning?

There is quite a debate as to whether the food comes into contact with BPA in metal lids. Since there is head space to allow the jar to build up a vacuum, many believe that the food never comes into contact with the lid. However, the food is expanding inside the jar as it's heated. With boiling food, and little head space, you can imagine the popping and bubbling and condensation coming into contact with the lid and then rolling back down into the food. BPA is activated by heat and acidic conditions. Boiling hot, acidic foods are a worst case scenario for canning and BPA contamination.

If you have any doubt, observe the food touching the lid when using a Weck jar. Look through the glass lid while canning with a boiling water bath. You'll see the activity.

Weck jars in a boiling water bath.

Weck jars in a boiling water bath.

Where to Buy Weck Glass Canning Jars

If you're serious about eliminating exposure to BPA through canning, then buying Weck jars is your first step.

Glass jars that have glass lids, like Weck, are more expensive than the standard wide-mouth canning jars with metal lids. They are difficult to come across second hand, but are available for sale online. Your best deal will be eBay or possibly Amazon. I started with a small collection to experiment with and have decided to expand my collection since they worked out so well.

Justifying the Expense of Weck Canning Jars

Reasons to help justify the expense of Weck jars:

  • Avoiding BPA (and plastic in general) means avoiding potential negative health effects.
  • Most canned tomato products available at the grocery store are metal cans with BPA lining or jars with lids that contains BPA in the lining or lid adhesive. If you are already investing in a more expensive brand that sells tomatoes in a BPA-free container, then investing in a more expensive brand of canning jars to offset it may not be that much of a reach. Who's to say these BPA-free brands are better anyway?
  • There is less waste in materials since the lids do not need to be replaced each year.
  • If you already have a collection of mason jars, they can be repurposed to store dry goods, crafts supplies, or even serve as vases.
  • Plastic lids are sold by Weck to use once the jar is opened and being temporarily stored in the refrigerator (not for canning). If you ever have unused Weck jars, they can be used as general purpose food storage containers. Food doesn't need to be in contact with the lid in this situation.
  • There are so many shapes and sizes available for every possible canning purpose.

If you still can't justify the extra expense, then see how your own organic garden can pay for itself, including purchase of Weck canning supplies.

This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.

© 2012 Melis Ann


Tori on March 02, 2020:

Dr. Dre, I searched and found an interesting article to answer your question. The article is called "Do Weck Jars Contain Lead?" by All About Jars. The findings of the study reveal that it is not possible for lead to leach into the food, even with high temps or acidic food. I hope that helps!

Dr. Dre on July 07, 2019:

What about the high levels of lead in consistantlyvfoind on weck jars? Levels of 300 - 400 which is very significant.

Jennica Wolf on August 13, 2017:

I forgot to add my email address! Please let me know on here or via email! jenibajo@aol.com Thanks so much!

Jennica Wolf on August 13, 2017:

Hello! I've been searching online all day about canning recipes with Le Parfait jars! I have tried them once, but it was a few years ago. What I'm wondering is if any canning recipes work with any canning jar? The headspace & processing times specifically! Thanks so much!

Melis Ann (author) from Mom On A Health Hunt on April 02, 2015:

Susan, I am in complete agreement which is why I avoid any products that claim to be BPA free. The claim does not ensure that there isn't another chemical taking the place of BPA, that may be more dangerous, and that we know less about. Instead, my focus when buying a product is to find an alternative that is chemical free. With the canning jars, the only option that I felt comfortable using was the glass jar with glass lid. Great point Susan - I hope consumers can avoid falling into the trap.

Susan Trump from San Diego, California on April 02, 2015:

Here is a side issue. These now identified products that are causing cancer are being avoided by consumers. New dangerous products are being developed as replacements with new names we have not yet tested and so, have no fear of yet. So if the BPA free now has a new dangerous element we will be in the dark for years to come. We have no proof the replacement content is clean because this is a consumer driven change rather than FDA. What do you think?

Melis Ann (author) from Mom On A Health Hunt on April 02, 2015:

That is great information ecogranny! Thanks for adding the list of possible uses for Weck jars in addition to canning. I do love all the different shapes they come in:)

Kathryn Grace from San Francisco on April 02, 2015:

Melis Ann, in response to your kindly reply to mine some ways below (Or is it above?), yes, I bought my Wecks for storing homemade ice cream because they had straight sides and wide mouths, making them easy to scoop. Later I found an even better ice cream solution, but I still use my Wecks for storage. They are wonderful for leftovers, for keeping sourdough starter, as well as for bulk dried goods, such rice, lentils and grains. But I'm looking forward to seeing how they do with canned foods.

Melis Ann (author) from Mom On A Health Hunt on April 02, 2015:

Thanks for your support Susan! I'm happy to have been awarded Hub of the Day, especially when it means more people will know about the issue of BPA in canning.

Melis Ann (author) from Mom On A Health Hunt on April 02, 2015:

Hi DzyMsLizzy - Weck is a German company and I believe is widely used in Europe. I have started to see Weck available in stores in the U.S. very recently and is readily available online. As consumers, we really need to drive the market by supporting these types of products and not always buying the cheapest option. I'm sure over time you will need to buy additional jars so when you do, go for what you really want:) I haven't tried the other glass/rubber ring brands, but I'm sure there are other options out there. Thanks for reading and happy to hear from fellow canners!

Susan Trump from San Diego, California on April 01, 2015:

Hoping you are proud of your hub of the day award. You should be. You've identified a real issue that is easy to overlook. Keep informing.

Liz Elias from Oakley, CA on April 01, 2015:

Interesting, and somewhat disheartening, as well. It is so frustrating that these corporations seem to insist on insuring that we cannot escape their evil poisons!

I just spent quite a bit of money over the last 3 years, re-investing in a water bath canning pot, and an assortment of brand-new mason jars and lids! I can't afford to replace them all now.

In fact, I've never heard of or seen 'Weck' jars in my entire lifetime. (I wonder if that's a UK brand?) I have, however, seen the old-style Mason jar, with glass lids, rubber seal rings, and an attached wire bail handle that is snapped down to secure the lid. Those are antiques; I don't recall seeing those recently.

Voted up, interesting and useful.

Melis Ann (author) from Mom On A Health Hunt on April 01, 2015:

Thanks for reading RTalloni! I hope you give the Weck jars a try for canning/food storage. They even look great on the counter top filled with dried beans and pasta:)

Melis Ann (author) from Mom On A Health Hunt on April 01, 2015:

Hi ecogranny:) It seems quality is really sliding in many products these days. I love the Weck jars, and even use them when I have some empty ones lying around for short term storage. They work great to store extra chicken stock, soups, and leftovers in the refrigerator. Enjoy your jam!

RTalloni on April 01, 2015:

Congratulations on your Hub of the Day award and thanks for thanks for this introduction to Weck products. Enjoyed reading this information.

Kathryn Grace from San Francisco on April 01, 2015:

I have a few Weck jars, as well as Fido and Le Parfait jars. I know my grandmothers used to can in Fido jars, but did not know how the seals worked until now.

Thank you so much for sharing this information. Not only do the Kerr and Ball lids have BPA, but they do not seal as well as they used to. Every time I can, I get at least 3 unsealed jars. Nor do the rest of the lids seal tightly. I've checked and re-checked the instructions. I'm doing exactly what they say, yet I don't get good seals.

I've noticed that the rubber in the seal is much thinner and more pocked with holes than it was when I was canning decades ago. I can't help wondering if using less rubber is the cause of the failed seals.

Next time I make jam, I'll use my old-fashioned jars with the rubber rings and see what happens. This is truly exciting news for a little old canner like me.

Melis Ann (author) from Mom On A Health Hunt on April 01, 2015:

Thank you ChitrangadaSharan! I'm honored that this hub on canning and BPA-free jars has been chosen as Hub of the Day.

poetryman6969 on April 01, 2015:

From what I have been hearing about BPA it is probably best to avoid it. Some useful canning advice.

Chitrangada Sharan from New Delhi, India on April 01, 2015:

Congratulations for HOTD!

Very useful and informative hub. I don't do much much canning but I will keep in mind your suggestions, when I do it.

Thanks for sharing, voted up!

Melis Ann (author) from Mom On A Health Hunt on October 06, 2013:

Thanks for the share on your hub chefsref! Glad you found the info on BPA in canning useful, especially because you do so much of it. Cheers!

Lee Raynor from Citra Florida on October 04, 2013:

Hey Melis

You have good tips here, I don't do a lot of canning so I never thought about the BPA in lids. I added a link to this Hub on my own Hub about BPA: https://hubpages.com/food/Canned-Food-Bottled-Wate...

Seems like we have similar views on the American food supply

Voted up


Melis Ann (author) from Mom On A Health Hunt on October 20, 2012:

Thanks for your comment mary615. I converted my Ball jars to drinking glasses instead of using them for canning. I will have to check out your hubs on canning. Thanks for the follow as well!

Mary Hyatt from Florida on October 20, 2012:

I have used Ball mason jars all my life. I never knew of any danger in using them. I buy all new lids whenever I can or preserve any foods. I see my Hub on preserving pecans in Ball jars is a related Hub to this one.

Very informative Hub here . I voted this UP, etc.

Melis Ann (author) from Mom On A Health Hunt on July 30, 2012:

I've started my Weck collection slowly by trying to save the money through gardening first. My hope is that one of these other manufacturers can make a similar product one day that would not be so expensive. Good luck with your canning!

Catherine Dean from Milledgeville, Georgia on July 30, 2012:

I have bought into the BPA-free items myself, but I am currently canning and freezing a lot of my own food. The Weck glass containers are extremely expensive compaired to the standard canning jars and lids. Being on a strict budget as most families are today, I would only be able to buy a couple a season. The amount of food that I am striving to put up would be cost astronomical amounts if I used Weck only. I do agree with everything you said, completely. I am no longer buying so many canned goods and replacing the void with my own. Thanks.

Melis Ann (author) from Mom On A Health Hunt on May 24, 2012:

Great point sdoldan ~ there is a lot of marketing out there that focuses on 'BPA-free', especially for baby products. It's really important to look at all sources of exposure to truly make a difference in our health.

sdoldan on May 23, 2012:

A topic I've become more and more interested in now that I'm a mom. "BPA Free" seems to be on many labels, but what good does it do us if we aren't aware of our practices in other areas of our food product(s) packaging? Understanding the importance of this topic is extremely helpful and encouraging to make the proper steps to be more cautious. THANK YOU!!!

Melis Ann (author) from Mom On A Health Hunt on May 22, 2012:

Thanks livingpah2004! I appreciate the vote-up!

Milli from USA on May 22, 2012:

Interesting article. Thanks for posting this hub. Voted up!

Melis Ann (author) from Mom On A Health Hunt on May 22, 2012:

Thanks for your comment. Unfortunately, scientists suspect that there are several compounds that leach out of plastics that are estrogenically active, some even more so than BPA. Avoiding plastic is really the best way to ensure exposure is limited.

Theresa Ventu from Los Angeles, California on May 21, 2012:

Interesting topic! I wonder what replaces BPA in plastic containers. Thank you Melis Ann for writing this informative article.

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