Ale is a type of beer that is brewed using a warm fermentation method, resulting in a sweet, full-bodied, and fruity taste. Historically, the term referred to a drink brewed without hops, but most modern ales are bittered with hops. Ale typically has a bittering agent to balance the malt and act as a preservative. The yeast used to ferment ale is often referred to as "top-fermenting" since it tends to rise to the top of the brewing vessel during fermentation. Ale was an important source of nutrition in the medieval world and was one of three main sources of grain in the diet in England at the start of the fourteenth century, along with pottage and bread. Ale was notably stronger during the 17th and 18th centuries and akin to modern-day barley wines. Today, ale is a popular beverage in England and is synonymous with beer.