Rēwena bread

Rēwena means both "bread made with potato yeast" and "the process of fermentation that causes bread to rise."[2] The Maori word for potato, 'riwai'[3] (sometimes spelled 'rewa'), is the root word of rēwena.[4]

Rēwena bread uses a pre-ferment starter, also called a ‘bug.’[5] It is created by boiling and mashing potatoes, then adding flour and sugar.[6] Māori potatoes (taewa) are commonly used for this purpose.[7] Kūmara, or sweet potatoes, may also be used.[8] The mixture is then allowed to ferment from one to several days, depending on the ambient temperature and humidity.[9] As with most sourdough breads, the starter can be maintained and used indefinitely, as long as the yeast is kept alive with regular feeding.[9] The potato starter and fermentation lends rēwena bread its characteristic sweet and sour taste.[9] The starter is then mixed with flour and water, kneaded, and baked, usually in a round loaf.

Rēwena may also be used to break the Maori taboo associated with visiting a cemetery by crumbling the bread over hands in lieu of washing with water.[10]

The "New World Rēwena Paraoa Baking Competition" is held during the Matariki Festival each year in New Zealand.[4]