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 The most common instruments used in Irish traditional dance music, whose history goes back several hundred years, are the fiddle, tin whistle, flute and Uilleann pipes. Instruments such as button accordion and concertina made their appearances in Irish traditional music late in the 19th century. The 4-string tenor banjo, first used by Irish musicians in the US in the 1920s, is now fully accepted. The guitar was used as far back as the 1930s first appearing on some of the recordings of Michael Coleman and his contemporaries. The bouzouki only entered the traditional Irish music world in the late 1960s.