The primary ingredient used to make beer is malted barley, although other grains such as wheat, corn, and rice can also be used. The process begins with malting, in which barley is soaked in water and allowed to germinate, developing enzymes that convert starches into fermentable sugars. This malt is then mashed and boiled with hops, which add bitterness and aroma, before fermentation occurs with yeast. The yeast consumes the sugars, producing alcohol and carbon dioxide. The fermentation process and variations in ingredients contribute to the diverse styles and flavors of beer enjoyed worldwide.