Guinness' 'burnt' flavour derives from malted barley and roasted unmalted barley, a relatively modern development, not becoming part of the grist until the mid-20th century. For many years, a portion of aged brew was blended with freshly brewed beer to give a sharp lactic acid flavour. Although Guinness's palate still features a characteristic "tang", the company has refused to confirm whether this type of blending still occurs. The draught beer's thick, creamy head comes from mixing the beer with nitrogen and carbon dioxide. It is popular with the Irish, both in Ireland and abroad. In spite of declining consumption since 2001, it is still the best-selling alcoholic drink in Ireland where Guinness & Co. Brewery makes almost €2 billion worth of the beverage annually.