Tiny Ethiopian grain, naturally gluten-free. Mild, slightly sweet. Used to make injera flatbread.
Substitutes
Buckwheat Groats — 1:1 by volume (buckwheat cooks faster — 15 min vs teff 20 min). Buckwheat groats provide teff's earthy, nutty flavor and small grain texture as a gluten-free ancient grain. Per USDA FoodData Central, both are high-protein pseudocereals: teff has 13.3g protein/100g and buckwheat 13.3g/100g — nearly identical. Per Davidson (The Oxford Companion to Food), both are ancient grains cultivated for millennia — teff in Ethiopia, buckwheat in Central Asia. Both are naturally gluten-free and cook by simple absorption method.
Amaranth — 1:1. Amaranth is another tiny gluten-free grain that cooks to a similar porridge-like consistency.
Millet — 1:1. Millet is a mild, small gluten-free grain. Less earthy than teff but similar cooking method.