Poi is a traditional staple food in the Polynesian diet
usually made from breadfruit, taro or plantain. Traditional Poi is
produced by mashing cooked starch on a wooden pounding board, with a
carved pestle made from basalt, calcite, coral or wood. Water is added
to the starch during mashing, and again just before eating, to achieve
the desired consistency, which can range from highly viscous to liquid.
Poi can be eaten immediately, when fresh and sweet, or left to ferment
and become sour, developing a smell reminiscent of plain yogurt. A layer
of water on top can prevent fermenting poi from developing a crust.