<P> The red cabbage ( purple - leaved varieties of Brassica oleracea Capitata Group ) is a kind of cabbage , also known as purple cabbage , red kraut , or blue kraut 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 . Furthermore , the juice of red cabbage can be used as a home - made pH indicator , turning red in acid and green / yellow in basic solutions . It can be found in Northern Europe , throughout the Americas , in China and especially in Africa . On cooking , red cabbage will normally turn blue . To retain the red colour it is necessary to add vinegar or acidic fruit to the pot . </P>
<P> The red cabbage ( purple - leaved varieties of Brassica oleracea Capitata Group ) is a kind of cabbage , also known as purple cabbage , red kraut , or blue kraut 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 . Furthermore , the juice of red cabbage can be used as a home - made pH indicator , turning red in acid and green / yellow in basic solutions . It can be found in Northern Europe , throughout the Americas , in China and especially in Africa . On cooking , red cabbage will normally turn blue . To retain the red colour it is necessary to add vinegar or acidic fruit to the pot . </P>
colour of red cabbage in acid and base
colour of red cabbage in acid and base
red in acid and green / yellow in basic solutions
red in acid and green / yellow in basic solutions