Place a plastic lid (or ceramic plate) that fits inside the jar or container. Add a weight such as a glass bottle filled with water. Or use small-batch fermentation weights and lids to secure the jar(s).
There should be enough brine to completely cover the contents when weighed down.
If not using fermentation tools, cover container with a dish towel or tea towel to keep out flies and dust. Secure with a rubber band, twist ties or elastic strap. Stash it in a cool, dark place– a cellar, under the stairs, or under the sink in the kitchen.
Label your container with the contents and date started. (I use blue painter’s tape and a permanent marker, and I always stick the label on the side of the container, rather than the lid. (Those lids have a notorious habit of switching jars when you’re not looking, usually in the middle of the night.)
Let ferment at room temperature 7 to 14 days. Fermentation time varies with the seasons and the climate.
Yeast and/or mold may form on the surface during fermentation. This is normal, especially when the top surface is exposed to air, and you are using fruit in the sauerkraut. Remove any weight and lids. and rinse them with water. Wipe, scrape, or scoop off surface yeasts or mold from the top and sides of the jar with a spoon, or clean paper towel, getting as much as you can. Don’t worry if you don’t get it all. Then stir the contents and re-pack the surface. Any residual mold will quickly be killed in the acidic environment of the brine. The contents are safe under the brine. If you want to ferment longer, replace the weight and lid, and check again in a few days.
When taste and texture are to your liking, transfer to jars and store in refrigerator.
Lasts up to 1 month in refrigerator.