Know your Jerusalem Artichoke
Know your Jerusalem Artichoke - Introduction
The Jerusalem artichoke, Helianthus tuberosus, is a species of sunflower native to the eastern United States, from Maine west to North Dakota, and south to northern Florida and Texas.
It is also cultivated widely across the temperate zone for its tuber, which is used as a root vegetable.
Know your Jerusalem Artichoke - Common names
Jerusalem artichoke is also called the sunroot, sunchoke, earth apple or topinambur.
Know your Jerusalem Artichoke - Botany
It 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 flower-heads 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 colour from pale brown to white, red or purple.
Know your Jerusalem Artichoke - Uses
Unlike most tubers, but in common with other members of the Asteraceae (including the artichoke), the tubers store the carbohydrate inulin (not to be confused with insulin) instead of starch.
For this reason, Jerusalem artichoke tubers are an important source of fructose for industry.
The crop yields are high, typically 16–20 tonnes/ha for tubers, and 18–28 tonnes/ha green weight for foliage.
Jerusalem artichoke also has a great deal of unused potential as a producer of ethanol fuel, using inulin-adapted strains of yeast for fermentation.
Know your Jerusalem Artichoke - Cultivation
Jerusalem artichokes are easy to cultivate, which tempts gardeners to simply leave them completely alone to grow.
However, the quality of the edible tubers degrades unless the plants are dug up and replanted in fertile soil.
This can be a chore, as even a small piece of tuber will grow if left in the ground, making the hardy plant a potential weed.
Know your Jerusalem Artichoke - Cuisine
The tubers have a consistency much like potatoes, and in their raw form have a similar texture to potatoes, but a sweeter, nuttier flavour; 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.
The inulin is not well digested by some people, leading in some cases to flatulence and gastric pain.