This may seem like a daft question and it probably is, but I’m very new and unsure so please be patient. I bought 3 kilner preserving jars, that come with vacuum seal screw top lids. I was worried about the gas building up inside my jar so turn the vacuum seal disk upside down so that it doesn’t seal like a vacuum but the jar is still closed. I’m wondering if this was the correct thing to do or should they in fact be vacuum sealed?

Also how well sterilised do the jars need to be, I boiled my jar in water before as per instruction that came with the jar. But because of where I live, when I took the jar out of the water later on they have a white powdery cover, due to the lime in the water. I dusted this of with a clean towel, but I’m wondering if I have sabotaged my sauerkraut?

Final question, I have lots of liquid being produced but not sure if it is bubbling, is it still working?

Purple fingers – I use the same jars as you, I put the lid on then loosen it slighty so any gas/liquid can escape, I clean in dishwasher then rinse with boiling water then drain, I dont sterilise. After packing the cabbage in the jar I get a whole cabbage leaf & cover the top of the shredded cabbage & tuck it in, this I discard when the sauerkraut is ready to use.

Another way to sterilized the jars is by removing the seals, putting them in a cold oven and bringing the temperature up to about 120 C, then letting them cool in the oven. I use this for bottling jams. If they are dirty or have been used before and need a scrub, Sodium metabisulphite soak helps.

Lakeland sell fermenting jars. They are really good and have an inbuilt pressure relief valve so no worries on that score. Only downside is that they are a bit expensive.