Red cabbage

The red cabbage (purple-leaved varieties of Brassica oleracea Capitata Group) is a kind of cabbage, also known as Blaukraut after preparation. Its leaves are coloured dark red/purple. However, the plant changes its colour according to the pH value of the soil due to a pigment belonging to anthocyanins. In acidic soils, the leaves grow more reddish; in neutral soils, they will grow more purple, while an alkaline soil will produce rather greenish-yellow coloured cabbages. This explains the fact that the same plant is known by different colours in various regions. It can be found in all of Europe, throughout the Americas, in China, and especially in Africa. The juice of red cabbage can be used as a homemade pH indicator, turning red in acid and green/yellow in basic solutions. When cooking, red cabbage will normally turn blue; adding vinegar or acidic fruit to the pot is necessary to retain the cabbage's red colour. Red cabbage needs well-fertilized soil and sufficient humidity to grow. It is a seasonal plant that is seeded in spring and harvested in late autumn. Red cabbage is a better keeper than its "white" relatives and does not need to be converted to sauerkraut to last the winter.