strains may also be present. Research has shown that when creating a naturally fermented starter, any naturally present S. cerevisiae will have died off after a few days. Sourdough is thus a stable culture of lactic acid bacteria and yeast in a mixture of flour and water. The yeast produces carbon dioxide which leavens the dough, and the bacteria produces lactic acid which contributes flavor. The bacteria metabolizes sugars that the yeast cannot, and the yeast metabolizes byproducts of bacterial fermentation. Commercially produced yeast will not accomplish these processes in rye flour. Rugbrød contains little or no added oils and is low in fat. Additional flavourings, other than salt, can include barley malt syrup or sugar. The bread is rich in protein and dietary fiber and not very sweet, unlike Swedish and German rye bread. Buttered is essentially the base for Danish open sandwich . See also Danish cuisine Pumpernickel Rúgbrauð Ruisleipä Schwarzbrot Øllebrød References External links Danish sourdough rye bread Danish cuisine Rye breads Sourdough breads