Fresh barley undergoes a process called malting, in which the kernel is steeped in water and allowed to partially germinate. This softens the kernel and develops the natural enzymes that will break down the raw starch in the grain into sugar. This process is stopped by heating the barley malt in a kiln.
In the process called mashing, the brewer mixes the malt with hot water. This converts the starch into sugars that yeast can digest.
After mashing, the sweet liquid, called “wort,” is drained into the boiling kettle, and hops, the flowers from a hop vine, are added. The heat sterilizes and clarifies the wort and also extracts bitter substances from hops that counteract sweetness from the malt. Hops also contribute aroma to the finished beer. The wort is then cooled and mixed with brewer’s yeast.
The yeast rapidly ferments the sugar to alcohol and carbon dioxide within one to two weeks.
When fermentation is complete, the beer is conditioned, clarified, and carbonated before being packaged into oxygen-free bottles, cans, or kegs to protect its freshness.