My sauerkraut brine seems slightly slimy but the batch otherwise seems normal--is it ok?

In general, slimy brine is indicative of a fermentation problem. Your brine might be too weak (what concentration did you use?), it may be too warm, your brine might not cover the vegetables, there might be some air bubbles trapped in your ferment.

This article suggests that in the early days of sauerkraut fermentation, the concentration of slime forming bacteria - Leuconostoc - is relatively high and towards the end of fermentation it's too small to measure. It doesn't say anything about slimy brine, but it's possible that the brine is temporarily slimy in the early days of fermentation and as the acidity increases it dissipates. I've never checked a ferment this early, so I can't comment on it.

Personally, I would let it continue to ferment for a week or two and then see whether the perceived sliminess has dissipated or increased. It's possible that it's too early to tell. Slimy vegetables, without a doubt, should be discarded.

References

• http://www.culturesforhealth.com/fermented-vegetables-troubleshooting-guide

After my 4th batch, I noticed the same thing: the kraut itself is crispy and tasty, but the liquid is like okra, mucilaginous. My problem with this batch of 3 quarts (mason jars with airlocks on each) was the brine covered the kraut, but when the cabbage floated upwards in the jar, the brine did not fully cover the kraut any longer, but I didn't catch it until 2 weeks into the 4 week process. It began fermenting, pushed brine out of the airlocks, but somehow pushed too much out and when it settled down, there was not enough. I opened the jars, took off the top layer which was orange/beige, added 3% brine to cover and replaced the airlocks. No further bubbling occurred. When I opened it again 2 weeks later, everything was still under the new brine, smelled great, tasted great, and I refrigerated it. I only noticed it a week later when we opened the jar again. Also, I did not use the outer cabbage leaf to cover the kraut in the jar, which held down the kraut better in my first batch. We have been eating the kraut, no stomach problems, no bad flavors, actually enjoying the flavor. Hope this helps.

I got a viscous slimey sauerkraut brine in a quart size mason jar batch. It's at the 10 day point in fermenting and it is on the heavier salted side (2 tablespoons of seasalt). It's been fermenting at approx. 68 degrees f., and still bubbling a tiny bit. Whereas the lighter salted jars has no more bubbling and no viscous slime. I think it''s because of it being more salted; contrary to one commenter''s conclusion that it would be because of not enough salt. No that's not it, it doesn't happen to my very very lightly salted batches. Anyway I just put more water in it, make sure the cabbage is covered, I'm sure in another week or two it will be just fine.

I've made about 10 batches of sauerkraut in past year in a Harsch crock, and the latest turned a little slimy. I've been reading about it online a bunch. I haven't found any clear answers, but the best I've found is that sliminess seems to come from having too much oxygen in the process. This would match my experience in this last batch because I forgot to put water in the water trap for the first couple of hours of fermentation.

I recently made a batch of kimchi and had the same experience - slimy looking brine. That said, I had added red pepper slices (which was new for me).

The kimchi tasted normal and I ate it and experienced no ill-effects.

I say it's good. IANADr

Edited to add: Here's a link to a dealing with fermented food that may have problems. It doesn't directly address the slimy water, but could be valuable.