Racking Beer to a Secondary Fermenter
Racking beer consists of transferring it from one fermenter to another after the primary fermentation process is complete. The primary purpose for racking beer is to improve clarity, age the beer for better flavor and in some cases protect it from off flavors produced by dying yeast. Another benefit behind racking is the ability to dry hop, check out How to Dry Hop? for more information on that process. The most important part of this process is to make sure the primary fermentation step is complete before racking.
How to tell when primary fermentaton is complete?
On average primary fermentation takes about 4-6 days for ales and 4-10 days for lagers to complete. You can confirm that primary fermentation is complete by noticing the activity on the airlock has slowed down to less than 2 bubbles a minute. With some beers both primary and secondary fermentation happen in the same vessel, check out our fermenting the beer article for more. Our recipe page will tell you what fermentation process is recommend for each specific style and recipe of beer.
What type of fermenter to rack into?
The best vessel to use during secondary fermentation is with out a doubt a glass carboy. Carboy’s tend to have less head space than a bucket for example, less head space is important to help prevent oxidation to the beer.
How to rack and for how long?
Racking into a secondary fermenter should be done using a auto-siphon if you are not draining out a bucket with a spigot. Before starting any thing make sure the carboy has been cleaned, sanitized and had enough time to dry. Regardless of method make sure the beer is flowing smoothly and not guzzling or splashing at any point. As a rule of thumb the higher the original gravity of the beer, the long the beer needs to stay in the secondary to reach peak flavor. From what I have experienced for lighter pale ales about 1.5-2 weeks is usually optimal, and about a month for a dry irish stout or any stronger beers.
Why should you not rack into a secondary fermenter?
Well after I convinced you it was a good idea for your beer and easy to do, here are a few problems with racking. The process of racking into a secondary fermentater greatly increases your chances of oxidizing your beer or introducing contaminates. Introducing oxygen or contaminates to the beer at this point could cause staling reactions that will be noticed in the flavor of the beer within a couple of weeks after bottling the beer / kegging.
Hope that helped. Feel free to comment below if you have any questions.