Wort is a brewing term that essentially means unfermented beer. It is beer before it is the beer that we drink. For homebrewers, it's important to understand what wort is and how it factors into the beer making process.
What Is Wort?
Many things must happen in the brewing process before we even get to the fermentation stage, which is when beer actually becomes beer. It all begins with making the wort, which will give the beer its fundamental flavors, including those of the grains and hops that the brewer's recipe calls for.
Think of the wort as a "beer starter." It is the sweet, malty liquid that begins by converting the starches of malted grains into sugar (the process of mashing). Hot water is added to this mash to allow the enzymes to finish the conversion from starch to sugar. This is the wort.
The Makeup of the Wort
The wort then goes through a process called lautering. During this stage, the grain husks and other solids are separated from the liquid wort.
Note: Homebrewers will often skip the mashing and lautering stages by starting out with a liquid malt extract.
The resulting wort—that now clean, sugary liquid which can be as much as 90 percent water—is now ready for brewing. The color of the wort is usually the same as the final product.
According to Oxford Companion to Beer (an essential book for any brewer), at this stage the carbohydrate and basic sugar content can look something like this:
- 12 percent monosaccharides
- 5 percent sucrose
- 47 percent maltose
- 15 percent maltotriose
- 25 percent higher saccharides (e.g. dextrin)
This is a general guide and will vary based on the grains used in the mash recipe.
Each grain will add different characteristics to the flavor of the finished beer. For instance, using rye in a rye IPA will give it a spicier flavor while the oats used for oatmeal stouts will produce a smooth, somewhat creamier taste.
Boiling the Wort and Adding Hops
The wort must be boiled or it will remain unstable. Boiling is a vital step because it sterilizes the liquid and halts the starch to sugar conversion.
Hops are also added to the liquid wort during boiling. They serve a few functions, though the primary purpose is to add the final flavors to the working beer. Hops are often added to the boiling wort in three stages:
- Bittering hops are added first to balance the sweetness of the sugary wort. These are typically given an hour in the boiling wort.
- Hops that are more floral, earthy, and/or citrusy in character are added right around 15 minutes before the end of the boil to add their desired flavors to the wort. These are often considered the "flavoring" hops.
- Finally, the finishing hops are added at the end of the boil or right after it is done. The focus of these hops is to add aroma to the wort.
After boiling, this now-flavored wort is cooled. It is ready for the yeast to be added and for the process of fermentation to begin.
Oliver G, Colicchio T. The Oxford Companion to Beer. New York, NY: Oxford University Press; 2011.