Sesamum indicum Seeds | Black Sesame
LATIN NAME: Sesamum indicum
COMMON NAME: Black Sesame
Plant Profile
Sesame is the oldest oilseed still in cultivation, with archaeological evidence from the Indus valley and Mesopotamian sites stretching back four thousand years, and it still looks like a wild plant. Sesamum indicum makes an upright, slightly angular annual 60-120 cm tall, with opposite leaves that change shape up the stem and tubular white to pink flowers in the leaf axils.
The seed is what the plant is grown for, and the black-seeded forms used in Chinese and Japanese cooking are the same species as the white-seeded types used for oil and baking. The difference is a single gene affecting seed coat colour, along with a corresponding difference in flavour: black seed is earthier and slightly bitter, white seed is milder and higher in oil.
Science & Biotechnology
Sesame chemistry is dominated by lignans. Sesamin and sesamolin make up around 1-2 per cent of the seed, and during roasting they convert partly to sesamol, a phenolic compound that gives toasted sesame oil its characteristic aroma and its unusual resistance to going rancid. That stability is not a small thing: sesame oil was one of the few cooking oils that could be stored without turning in hot climates, which is part of why the crop spread so widely.
Sesamin also inhibits delta-5 desaturase in fatty acid metabolism, an effect studied in relation to lipid profiles and vitamin E retention, and small trials have reported modest reductions in blood pressure and cholesterol markers. The mineral content is more striking than the pharmacology: sesame is one of the richest plant sources of calcium, at roughly 975 mg per 100 g of whole seed, although the oxalate and phytate content limits how much of it is absorbed.
Uses & Benefits
In the kitchen the seed is used whole, ground into tahini and halva, pressed for oil, and scattered over bread and rice. In Chinese practice black sesame, hei zhi ma, is a tonic food rather than a medicine, taken in congee and pastes, and the claim most often attached to it is for hair and skin rather than for any specific condition.
As a garden plant it is grown for the flowers, which are small but produced over a long period, and for the seed heads, which are decorative as they dry. It is also a useful bee plant in a hot summer, since it flowers when many annuals have finished.
Growing from Seed
Sesame needs warmth more than anything else. Sow 1 cm deep once the soil is above 20°C, and hold at 22-25°C for germination, which takes five to ten days. Cold soil causes the seed to rot, and a late start is better than an early one.
Thin to 20-30 cm apart in full sun and keep the plants weed-free while young, since they are slow to compete. Water moderately until flowering, then keep steady moisture; drought at flowering causes the capsules to abort. Harvest when the lower capsules turn yellow and the plants begin to lose leaves, cutting the stems and drying them upright over a cloth, because the capsules shatter when fully dry.
Our Take
Sesame is a crop for a long, hot summer, and it will disappoint in a cool one. Where it works it is handsome, useful and almost entirely untroubled by pests, and the seed you harvest will taste noticeably fresher than anything on a shelf.
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