Photo: BPA-free canning lids

Home canning is a great sustainable practice. Especially BPA-free.(Credit: Chiot's Run via Flickr)

Ever wanted to do your own canning but were turned off by the thought of preserving your food in BPA? Good news — BPA-free canning lids are available. And I'll tell you who makes them. However, although BPA-free canning lids are easy to find, they may not be the answer to your toxin-free food-preservation efforts.

A popular BPA-free option is the Tattler Reusable Canning Lid. It's made from polyoxymethylene copolymer (POM), which is a fancy way of saying that it's a BPA-free plastic. Yup, plastic! And it's not without its own cause for concern. This rigid compound has trioxane as a key compound — in other words, formaldehyde.

The jury is still out on the relative safety of ingesting trace amounts of formaldehyde. Fans of the BPA-free lids point out that formaldehyde isn't released from polyoxymethylene until temperatures reach 250 C (482 F), well above the processing temperature for canning. Critics note that other factors — like acidity — can affect the release of formaldehyde from plastic.

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So what's a concerned canner to do? First, let's be clear — my hat is off to all home canners. No matter how you look at it, putting up local food in re-usable glass jars to be eaten all season is inherently green. And choosing to eat from glass jars, instead of BPA-laden cans, can only be good for your health.

Now for the nitty-gritty best practices. I vote for buying traditional glass lids from thrift stores and markets whenever possible. Barring that, consider using the boiling water bath (BWB) method instead of pressure canning. If adequate space is left in the jar, proper BWB canning doesn't require the food to touch the lid. Finally, you may want to try preserving some foods using other methods, like freezing and dehydration.

Happy canning!

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