Testing Your Old Crock for Lead

Maybe it’s happened to you. You are at a flea market and you see a great old crock for super cheap. There aren’t any cracks inside and you’ve been meaning to ferment some vegetables. So you snag it and bring it home and then the questions begin. Don’t some ceramics have lead in the glaze? Is it safe to put food in there? How can I find out? Is there a way to check the brand? Do those blue numbers on the side mean it’s food-safe?

My Flea Market Crock to Lead Test

Well, it happened to me and I searched and searched the makers of my crock as well as info about lead in glazes and finally ended up calling my Cooperative Extension office. The woman I spoke with said there was only one sure fire way. Test it.

It’s easy enough to find an inexpensive lead testing kit. I bought a LeadCheck kit at my local big box hardware store for about $15 dollars. Then just follow the instructions in the package.

Lead Testing Kit with the Bottom of the Crock

The tricky part for crocks is that you need to chip into the glaze so the testing material can get up in that layer. Sounds easy enough, but glazes can be super strong – it’s like chipping into a rock (while trying not to damage your crock). I ended up using the pointy corner of a screwdriver to kind of drill in on the bottom of the crock.

Here are the photos of the process.

Scratching the crock glaze to test for lead

Scratching the Crock Glaze

Chipped Glaze for lead testing

Chip in the Glaze – it’s small, but big enough!

The individual Lead Testing Tube





Swabbing the crock with the yellow solution

Confirming the lead tester as valid on the enclosed lead filled card

Comparison of the leaded card with  the swabbed crock chip

And we’re clear! No lead in this crock and it’s ready for some nuka pickles.

Now, if you’re like me and have mild OCD, you might double or even triple check this test. To experience my extraordinary thoroughness for yourself, click here. Otherwise, I hope you feel empowered to buy that cool old crock at the flea market this summer and get fermenting!

16 thoughts on “Testing Your Old Crock for Lead

  1. I put “lead testing crock” into Google, but I didn’t really expect to find something that so exactly answered my question. Now I need to do this and find out if I’ve been eating lead-laced sauerkraut for the past year.

  2. Milagros on said:

    Thanks so much for posting this. I just bought 4 crocks on Craigslist and did not consider the possibility of lead in the glaze. I will test them soon.

  3. Hi. Loved your post re. testing crocks for lead. My question is how do you know the inside is leadfree if you only tested the outside. I have an old crock and the outside is a different color (tab) than the inside (dark brown).
    Thanks. Robbie

    • Hi Robbie and thanks for your question. I never expected this little wrinkle! To be absolutely sure that the interior glaze is lead free you’re going to need to test it too. Unfortunately for you that means chipping into the glaze where you can see it. My suggestion would to be to do it on the rim if possible so your food doesn’t come into contact with the chip. You don’t need to make a huge chip – just enough to get the testing solution down into the glaze. Hope that helps!

  4. alain aldama on said:

    I’m going to use this protocol to test some large pots that I use as a container garden. Thank you for the perfect solution.

  5. Marian on said:

    If we get crocks second-hand and don’t know the history, and they have been used in the garden, or as containers for plants, can they be cleaned enough or do we need to worry about botulism microbes or anything else like that?

    • Marian, it’s difficult for me to say if your crocks can be cleaned enough without seeing them. If they have cracks in the glaze, I wouldn’t use them because food can get trapped down in those cracks. If the glaze is smooth and you can get the crock clean, test it for lead on the outside, as I suggest in the post, before you use it for food. I don’t worry about botulism when fermenting vegetables because botulism can only create its deadly toxin in a truly anaerobic environment (think water bath canning). I hope that helps!

    • Michaela on said:

      Hi Hannah,

      It will depend on the brand of testing kit that you buy, but the one I used had about 5 tests in it, so you should be good to test a few crocks with one package. Happy fermenting!

  6. Megan on said:

    I’ve heard the home lead testing products aren’t accurate. I don’t know who to believe! I bought a water crock from my thrift store and now I’m not sure if I should use it for my kombucha. I could buy a glass one for $15 though and not worry about the lead. What are your thoughts?

    • Michaela on said:

      Hi Megan. If the crock you purchased at your thrift store is for water, then the glazes used should be food safe and free from lead. It is primarily the older crocks that may have been used for gardening or something else entirely that could have lead in the glaze. I hope that helps!

  7. … the questions begin. Don’t some ceramics have lead in the glaze? Is it safe to put food in there? How can I find out? Is there a way to check the brand? Do those blue numbers on the side mean it’s food-safe?

    This is me always, these Exact. Same. Questions. Thank you for your post!

Leave a Reply