Cleaning a Harsch Crock

[Christopher Weeks]

If you were the potter who made the crock, fixing it would be relatively easy. You'd get it hot (not crazy hot, just more than warm) and put a little liquid glaze where the flaw is. Because it's hot, it drives the water out and causes the glaze solids to stick right there. Then you'd just run it through the glaze-fire process again.

But to do that, you have to know how hot the glaze (and clay body) are expected to be fired. I'm not capable of making guesses like that about someone else's pottery. (I'm not sure if anyone can do that reliably, but maybe.)

One thing that would be fairly safe, assuming it's stoneware...

(If you put a bit of spit on the bottom of the crock, where there's no glaze, does it soak in or just sit there? If it soaks in, I have no help for you. If it sits there, we'll call it stoneware.)

...is to patch the mis-glazed area with a low-fire glaze and then fire the crock up to whatever temp that glaze needs to vitrify. My guess is that it won't stick *well*, but it might stick *well enough*.

Also, if it is stoneware, you're probably OK using the crock even with the fault. The texture of the unglazed clay will tend to harbor moisture and cultures more than the glazed surface does, but the stoneware body is probably partially vitrified (turned into glass) and since the fault is at the bottom, rather than the side where the top of the brine level might be, it's probably pretty safe if you use it for fermentation and then clean it and then use it and then clean it.

[Gutted]

Thank you for your helpful and insightful reply Christopher.

If you were the potter who made the crock, fixing it would be relatively easy. You'd get it hot (not crazy hot, just more than warm) and put a little liquid glaze where the flaw is. Because it's hot, it drives the water out and causes the glaze solids to stick right there. Then you'd just run it through the glaze-fire process again.

But to do that, you have to know how hot the glaze (and clay body) are expected to be fired. I'm not capable of making guesses like that about someone else's pottery. (I'm not sure if anyone can do that reliably, but maybe.)

From the little that I could find out about them on the internet, they are supposed to be pit fired and made using a mould rather than being hand turned which the Harsch crocks are meant to be.

One thing that would be fairly safe, assuming it's stoneware...

(If you put a bit of spit on the bottom of the crock, where there's no glaze, does it soak in or just sit there? If it soaks in, I have no help for you. If it sits there, we'll call it stoneware.)

I did try with spit and it didn't seem to sink in. I tried water and that didn't either. The area is a little rough, with a very slight shine to it, but not a lot.

...is to patch the mis-glazed area with a low-fire glaze and then fire the crock up to whatever temp that glaze needs to vitrify. My guess is that it won't stick *well*, but it might stick *well enough*.

Also, if it is stoneware, you're probably OK using the crock even with the fault. The texture of the unglazed clay will tend to harbor moisture and cultures more than the glazed surface does, but the stoneware body is probably partially vitrified (turned into glass) and since the fault is at the bottom, rather than the side where the top of the brine level might be, it's probably pretty safe if you use it for fermentation and then clean it and then use it and then clean it.

Thank you for explaining, maybe I could use it. I've had it ages and I have never used it before and the glaze is pretty terrible all over. I complained and I was sent a smaller replacement, the size that I had paid for, which was a lot better but even that was not perfect. He must of hoped that I might accept the poor quality one because it was larger. He tells me that the latest ones are much better but the whole experience hasn't done my confidence in them a lot of good. I am very wary of purchasing another. German quality isn't always as high as some advertising makes it out to be.