Originally stored in unlined wooden vessels known as tuns, the beer would pick up some lactic sourness as a result of wild yeasts and tannins in the wood. The result was a beer dubbed 'stale' by drinkers: it was one of the components of the early, blended Porters. Old Ales, contrary to expectation, do not have to be especially strong: they can be no more than 4% alcohol. Neither do they have to be dark: Old Ale can be pale and burst with lush sappy malt, tart fruit and spicy hop notes. Darker versions will have a more profound malt character with powerful hints of roasted grain, dark fruit, polished leather and fresh tobacco. The hallmark of the style remains a lengthy period of maturation, often in bottle rather than bulk vessels. Old Ales typically range from 4% to 6.5%.