An Overview of the Beer Brewing Process

This is intended to be a short and simplified overview of the brewing process. As this is a general overview, there are many different ingredients and methods used to brew beer that will not be covered in-depth, so keep this in mind as you read. We will focus strictly on the processes involved, not the equipment, since the basic process can be done in a similar fashion on a small scale at home, or in a large production facility.

The Ingredients
Let's start with the individual components; there are four ingredients in your basic beer: malted grain (usually barley), hops, yeast, and water.

Grain:
Yeast need sugar to feed on and to produce alcohol. We will get the sugar from the grain, but first it needs to be 'malted'. When grain is malted, it is wetted and allowed to grow just a little, to the point just after sprouting, in order for the grain to start producing enzymes that will later (during the mash) allow it to break down the starches held within it. This malting process is halted by drying out the grain in order to keep it from developing too much and using up the starch and sugar for energy. The enzymes necessary to produce sugar from starches will be activated by the brewer during the mash (which we will talk about later).

Hops:
The hops grow on a vine, and are actually a green flower. The hops are used for bittering, flavoring and aroma. The bittering is necessary to counterbalance the sweet flavor of the malt, otherwise you would end up with a cloyingly sweet and unbalanced beer. In some beers the hop bitterness is barely noticeable (Oktoberfest or Märzen style beers), while it is the primary flavor component of an India Pale Ale (IPA).

Yeast:
The yeast is the ingredient in beer that actually turns the sugar (from the malted barley) into alcohol. Yeast is a single-celled fungi that eats the sugar, and as a by-product, produces carbon dioxide and alcohol. There are many different strains of yeast for brewing, but the main two types are ale yeast and lager yeast, which produce ales and lagers (obviously).

Water:
Well, the water is water! There are many different variables involved in the water that can affect the finished beer; mineral content, pH, etc., but for simplicity, we will leave these out.

The Brewing Process
Now that we've got the main ingredients covered, let's talk about the brewing process.

The Mash:
Mashing is the process in which the malted grain is steeped in hot water (usually between 150 F and 160 F) to release the enzymes produced during malting. These will then break down the starches in the grain into simple sugars that the yeast can use. The mash usually lasts from 60 to 90 minutes. During the mash, the sugars dissolve into the water producing wort (pronounced wert), which is the unfermented beer. At this point the wort is basically sugar water. At the end of the mash the wort is drained into the boil kettle, ready for the next step.

But before we move on, there are still residual sugars left in and on those grains! These sugars will be rinsed off in what is called the 'sparge'. More hot water is added to the grains, mixed, and let sit for a couple of minutes, then added to the wort collected earlier in the boil kettle.

The Boil:
At this point the wort collected from the mash is boiled, usually from 60 to 90 minutes. Boiling sterilizes the wort so no other microorganisms grow in it besides the yeast added by the brewer. Infection by anything other than brewer's yeast can cause off flavors in the finished product. Boiling is also the time when hops are added, as the compounds in hops used for flavoring and bittering are extracted in boiling water.

Hops added at the beginning of the boil add bitter compounds to the wort, and most of the hop flavor is volatile and therefore boiled away. Hops added closer to the end of the boil add a hoppy flavor to the beer, as there is less time to extract the bitter compounds. Hops added right at the end of the boil or even afterwards add hop aroma to the beer. When the hops are added, the amount, and the type of hops used are determined by the style of beer being brewed.

The Fermentation:
Yeast are added to the wort after it has cooled to a temperature suitable for the yeast to thrive in, approximately 65 F to 75 F. The yeast 'eat' the sugars present in the wort and as a by-product, produce carbon dioxide and alcohol. After several days to several weeks, this process is complete. The yeast will fall out of suspension and compress in the bottom of the vessel you have been fermenting in, and you have beer. The last step is to carbonate and package your beer.

Packaging:
At this point, the beer needs to be carbonated, by either bottle conditioning, or forced carbonation.

When bottle conditioning, the finished beer has a little sugar added to it, then it is put into bottles and sealed. The remaining yeast feed on this sugar and produce carbon dioxide, but since the bottle is sealed, the gas has nowhere to go, and is absorbed into the beer. Thus, you end up with a carbonated bottle of beer.

When using force carbonation, pressurized carbon dioxide is added directly to the beer until the proper amount is absorbed. It is then packaged in either bottles or kegs, ready to drink.

Further Reading
That's it, the basic brewing process. For much more in-depth information, I strongly recommend How to Brew by John Palmer, available free online.