A traditional Maori yeast-free bread made with a starter or bug which, like the starter for sourdough, can be kept indefinitely as long as it is fed. The starter is made by boiling and mashing potatoes (or kumara) and then adding flour and sugar. The mix is left to ferment for about three days in cold weather but can be ready in one day in warm weather. Rewena bread has a characteristic sweet/sour taste. It is sold commercially by artisan bakers such as Wild Wheat in Auckland. For more, see Peter Gordon's guide to using indigenous New Zealand foods.