Masi / Ma (Fermented Breadfruit — Pan-Pacific Preservation)

Masi (also ma, mahi, or bwiru depending on the island group) is fermented breadfruit — a Pacific preservation technique in which ripe breadfruit (Artocarpus altilis) is buried in leaf-lined pits and allowed to undergo anaerobic lactic-acid fermentation for weeks, months, or years. The result is a dense, sour, shelf-stable paste that serves as a famine food, a travel provision, and a long-term starch reserve. The technique is documented across central and eastern Polynesia (Samoa: masi; Marquesas: ma; Tonga: mahi; Caroline Islands: bwiru; Cook Islands: ma) and represents one of the Pacific's most sophisticated preservation methods. The FAO Pacific Island Food Composition Tables (2nd ed, 2004) document masi as a preserved food with significant nutritional retention. The fermentation converts the breadfruit's starches into lactic acid and other organic acids, producing a sour flavour and a low-pH environment that prevents pathogenic bacterial growth. The technique is the Pacific expression of the global principle of anaerobic pit fermentation — related to Ethiopian enset (false banana, buried and fermented for months), Korean kimchi jangajji, and European sauerkraut in mechanism (lactic acid preservation), though not in lineage.

Ripe breadfruit (Artocarpus altilis — the fruit must be fully ripe, soft, and starchy, not the firm, green fruit used for roasting) is peeled and cored. The flesh is kneaded or mashed to break down the cell structure. A pit is dug in the ground and lined with banana leaves, ti leaves, or heliconia leaves — the leaves create an anaerobic barrier. The mashed breadfruit is packed tightly into the pit, layer by layer. Each layer is covered with leaves. The pit is sealed with a final layer of leaves, then earth or stones. The breadfruit undergoes anaerobic lactic-acid fermentation. Duration: minimum 2–3 weeks for a mild ferment; 3–6 months for a deeply fermented product; traditional practice in the Marquesas produced ma that was stored for years (some sources report 10+ years for extreme famine reserves). The fermented product darkens from white to grey-brown, develops a strong sour aroma (comparable to sourdough or yoghurt), and becomes a dense, sticky paste. To use: portions are removed from the pit, kneaded with fresh coconut cream, formed into cakes, and baked on hot stones or in an umu.

Fresh masi has a sour, tangy, yeasty flavour — comparable to mature sourdough starter. The sourness increases with fermentation time: mildly fermented masi (2–3 weeks) has a gentle tang with recognisable breadfruit flavour. Deeply fermented masi (months to years) has an intense, sharp acidity with cheese-like or yoghurt-like aromatic complexity. When mixed with coconut cream and baked, the sourness mellows and the coconut fat balances the acid — producing a cake that is simultaneously sour, sweet, and starchy. The aroma of freshly opened masi is strong — a deep, fermented, slightly funky scent that may be off-putting to those unfamiliar with fermented foods but is familiar and appetising to Pacific Islanders who grew up with it. Species: Artocarpus altilis (breadfruit) — the seedless cultivar is preferred for masi because it mashes more smoothly. The seeded breadfruit (Artocarpus camansi, breadnut) is less suitable because the seeds create inconsistencies in the paste.