Salt and time make sauerkraut
Sauerkraut is cabbage and salt, nothing else. The salt pulls water out of the cabbage to make its own brine. Lactic acid bacteria already on the leaves eat the sugars and make the sour taste.
Keep the cabbage under the brine
Keep every shred under the brine, since mold needs air and the good bacteria don't. Use about 2% salt by weight (20 g per kg of cabbage) and keep the jar at 18 to 22°C. Taste from day 7. If it smells rotten or grows fuzzy mold, toss the batch.
Test yourself
Questions from the interactive lesson, with the answer and the why.
What makes fermented cabbage sour?
Lactic acid made by bacteria eating sugars. This is the same acid that sours yogurt.
True or false: Cabbage fermenting under its brine is protected from mold.
True. Mold needs air and the lactic acid bacteria do not, so cabbage under brine stays protected.
What went wrong? You leave some cabbage poking out above the brine for two weeks. Fuzzy spots show up on it.
Cabbage above the brine is exposed to air, so mold grew. Keep everything submerged, using a weight if needed.
Fill the blank: Fermentation works because salt helps the cabbage release its own ___.
Fermentation works because salt helps the cabbage release its own brine. The liquid it releases covers the cabbage.
The same cabbage sours in about a week in a warm kitchen but takes a month in a cool cellar. Why?
The bacteria work faster in the warmth. Cooler spots give a slower, milder ferment.
A week of sauerkraut
Watch cabbage turn sour.
Do the 30-minute experiment