Across the Pacific Islands, breadfruit (Artocarpus altilis) was traditionally preserved by fermenting it in pits: the starchy fruit was packed into pits in the ground and left to turn into a sour, strong-smelling paste, which was then cooked. The practice goes by many local names – in the Marshall Islands, for example, the paste is bwiru – and has been studied far less than most of the ferments on this site.
What’s Documented
The anthropologist Nancy Pollock’s survey of breadfruit fermentation in Oceania is the main overview (Pollock, 1984). Among its points:
- Fermented breadfruit wasn’t only a famine store. In the Marquesas and in Truk (Chuuk) it was mixed with fresh breadfruit as part of the everyday, highly valued food supply, and Pollock argues it was made as much for its flavour and texture as for keeping.
- On Namu in the Marshall Islands, bwiru paste was eaten two to three weeks after the breadfruit was put into the pits.
- Early European visitors were unimpressed and called it “cheese” because of its strong smell.
- Where and when pit fermentation began hasn’t been established, though archaeological work has suggested it is old in West Polynesia.
The microbiology of pit-fermented breadfruit hasn’t been worked out. What laboratory work shows is that some starch-digesting lactic acid bacteria can break down cooked breadfruit, turning a thick, sticky slurry semi-liquid and raising its resistant starch (Haydersah et al., 2012).
Why There’s No Home Recipe Here
We don’t give a method for fermenting breadfruit at home. There’s no tested recipe with measured salt, time and acidity, and breadfruit is a low-acid starchy food: packed airless for weeks, it is only safe if it reliably sours, and if it doesn’t, it’s the kind of food in which botulism can develop (CDC). Traditional pits rely on knowledge and conditions a jar on a kitchen counter doesn’t reproduce.
For starchy ferments that do have well-described methods, see Hawaiian poi, made from cooked taro, West African fermented cassava, and Ghanaian kenkey. Fresh breadfruit itself is excellent roasted, boiled or fried, like a potato.