Quick bread leavening agents include a weak base, such as baking soda (sodium bicarbonate) plus a weak acid, such as cream of tartar, lemon juice, or cultured buttermilk, to create an acid–base reaction that releases carbon dioxide. (Quick bread leavened specifically with baking soda is often called "soda bread".) Baking powder contains both an acid and a base in dry powdered form, and simply needs a liquid medium in which to react. Other alternative leavening agents are egg whites mechanically beaten to form stiff peaks, as in the case of many waffle recipes, or steam, in the case of cream puffs. Nevertheless,
Irish traditional music music and instrumentation, Celtic themes and imagery, concept albums based on Irish mythology in a way that entered the territory of progressive rock all powered by a hard rock sound. Horslips are considered important in the history of Irish rock as they were the first major band to enjoy success without having to leave their native country and can be seen as providing a template for Celtic rock in Ireland and elsewhere. Traditional music, especially sean nós singing, played a major part in Irish popular music later in the century, with Van Morrison, Hothouse Flowers and Sinéad O'Connor using traditional