Leaky Jars

Hi Kirsten,

I started making sauerkraut to sell at two farmer’s markets where they have created a terrific small business for me. However I have two major problems.

The first is mould in the jars. After the sauerkraut is decanted into the jars ready for sale, I notice that after a couple of weeks, in the fridge, they often have mould and taste awful. Sometimes if I catch them early I can scrape off the top inches and everything is fine underneath and we eat it ourselves. I can’t weigh the kraut down inside a jar for sale, so I was wondering if you had any tips there.

The second problem is that often people say they love my pickles, all thanks to your recipes, and would I post them down to them? But I can’t because my jars leak! No matter how much I tighten the twist off lids they still leak like mad. Which I don’t mind as it seems to be an outlet for fermenting gasses to escape and not build pressure up in the jar, but the customers don’t like my leaky jars either, especially the poor lady who had a very enthusiastic beet kraut bubble up in the boot of her car and left a big stain! She is not a fan any more... I’ve noticed that the sauerkraut from health food shops that is labelled raw and live do not have leaky jars but I can’t work out what they do to them. If you can cast any light there I would be profoundly grateful.

Thank you so much for launching us on this amazing fermenting journey,


I am glad to hear of your successes.

I am sorry for your trouble. I had to smile at the story of the beet kraut. We also had some overactive beets when we were in business, people weren’t happy when it made their bags look like a veggie murder scene.

Oxygen is getting in your jars. I suspect your lids aren’t airtight. If they were there is no way that the mold could grow, also this look like surface yeast to me not mold. The ferment covers itself with a layer of CO2 when there is no new oxygen getting in the jar. Since you are having a regular issue and the jars are leaking it tells me that the jar style you are using isn’t working.

When we taught in Chile a few months ago we bought jars that should have worked but they were not airtight and it caused a problem. The lids were a similar style to the one pictured. I would suggest finding a different jar source. When we were in business we used jars made for canning and they had a solid seal, even without the hot water bath. Some jars will only seal when boiled.

I hope that helps!