Jerusalem artichoke is a herbaceous perennial plant growing to 1.5-3 metres (4 ft 10 in-9 ft 10 in) tall with opposite leaves on the lower part of the stem becoming alternate higher up. The leaves have a rough, hairy texture and the larger leaves on the lower stem are broad ovoid-acute and can be up to 30 centimetres (12 in) long and the higher leaves smaller and narrower. The flowers are yellow, produced in capitate flowerheads which are 5-10 centimetres (2.0-3.9 in) in diameter, with 10-20 ray florets. The tubers are elongated and uneven, typically 7.5-10 centimetres (3.0-3.9 in) long and 3-5 centimetres (1.2-2.0 in) thick, and vaguely resembling ginger root, with a crisp texture when raw. They vary in color from pale brown to white, red or purple. The tubers are sometimes used as a substitute for potatoes: they have a similar consistency, and in their raw form have a similar texture, but a sweeter, nuttier flavor; raw and sliced thinly, they are fit for a salad. The carbohydrates give the tubers a tendency to become soft and mushy if boiled, but they retain their texture better when steamed. Jerusalem artichokes have 650 mg potassium per 1 cup (150g) serving. They are also high in iron, and contain 10-12% of the US RDA of fiber, niacin, thiamine, phosphorus and copper. Jerusalem artichokes can be used as animal feed, and, while they must be washed before being fed to most animals, pigs forage and safely eat them directly from the ground. The stalks and leaves can be harvested and used for silage, though cutting the tops greatly reduces the harvest of the roots. In Baden-Wrttemberg, Germany, over 90 percent of the Jerusalem artichoke root is used to produce a spirit called "Topinambur", "Topi" or "Rossler".