While many homebrewers are content with the quick results of their primary brew, at some point secondary brewing catches their interest. Much has been written about the pros and cons. However, the benefits appear to be in the eye of the beholder. After all, why would you want to lengthen your brewing process?
So what is secondary brewing, and why can it be beneficial? During the primary brewing stage, fermentation peaks after a couple of days. At the end of this phase, grain, yeast, and hops are left over as sediment.
Leaving the beer in contact with this sediment adds bitterness and a cloudier appearance to the brew. Additionally, the plastic buckets used for the primary fermentation gradually seep oxygen. This gives the beer an oxidized flavor.
To overcome these issues, the beer is transferred to a different container. This is the secondary fermentation stage. Usually, homebrewers transfer the beer to a glass carboy. Here the secondary fermentation takes place in a few days to several months. The benefit of this aging is a clearer, smoother tasting beer.
The shortcomings of this secondary process are that, through the additional racking, there is a danger of introducing both bacteria and oxygen to the brew. Both of these can have adverse effects on your beer's flavor. Luckily, meticulous equipment hygiene and minimizing splashing can overcome this problem.
One excellent solution brewers have found is to use conical brewing containers in the primary phase. This minimizes the contact area between the sediment and the beer. Once the initial fermentation has taken place, a valve is opened at the bottom of the cone, flushing out the sediment. Some believe this makes secondary fermentation unnecessary.
Ultimately, the choice is subjective. Certain beer recipes call for secondary fermentation. If you are willing to experiment, you can decide whether the process of secondary fermentation makes a significant difference in your brew's flavor.