Secondary fermentation and why it makes me crazy

HomeBrewTalk.com - Beer, Wine, Mead, & Cider Brewing Discussion Community.

Help Support Homebrew Talk:

Why must we all misconstrue secondary fermentation?

In this article I will attempt to set straight how to use and how not to use a secondary fermenter. There are two basic schools of thought for fermenting ales:
1. Primary only
2. Primary and Secondary: However, most people do not know what that means. Let us start with a primary only fermentation. In this method, the brewer transfers sweet wort to the fermenter and pitches yeast. As the yeast reproduce and eventually start fermenting the wort into beer the brewer allows the fermentation process to complete in the primary fermenter without racking from the trub and yeast cake. The best idea then is to allow the beer to sit in the primary fermenter for a time after terminal gravity has been reached. General consensus is to allow the beer to sit for 2-3 weeks on the cake. What is happening after fermentation is what is called the conditioning phase when the yeast cleans up the beer by re digesting and precipitating out unwanted chemicals and compounds. This cleans the flavor and profile of the beer and is very desirable. The primary and secondary schedule is a bit more complicated but can be used to great effect. In a two stage fermentation, the brewer is attempting to time the inflection point between primary and secondary stages (or attenuative and conditioning stages) of fermentation and to rack the beer off the trub at this point.
The point is to remove the protein, and other garbage along with any dead yeast cells from the fermenter before conditioning occurs. The common mistake is that people think this point is when the fermentation has stopped. THAT IS NOT TRUE. To properly use a secondary fermenter, the beer must be racked off the trub when the beer is 2/3-3/4 attenuated and is still actively fermenting. The general rule of thumb (read non-accurate way) is to rack to secondary when the bubbles in your airlock drop to 4 to 5 per minute. The beer will still be turbid at this point although a thick trub layer should be visible at the bottom of the fermenter. When you rack the beer into your secondary fermenter there will be enough yeast in solution to properly attenuate the beer and complete the conditioning. The advantage is that in a clean or lighter beer, you have removed all the junk from your fermentation thereby hopefully removing bad taste compounds that could leach into your beer. On a conical fermenter, or in a commercial setting, this racking to secondary would be synonymous with the first trub dump out the bottom of a conical. In a homebrew setting, we are removing the beer from the tub instead of the other way around. Where many people go wrong, is to think they are using a secondary fermentation schedule and rack to a second vessel immediately after fermentation has ceased and terminal gravity is met. What these people are doing is using a primary only fermentation method, but robbing themselves of the conditioning phase. Basically, at the end of fermentation (at full attenuation) all or most of the yeast has dropped out of suspension and is sitting at the bottom of the fermenter. That is why the beer is clear. If you remove the beer at this point, there will not be sufficient yeast in the secondary to condition the beer, potentially leaving the brewer with a less than optimal beer.
Now, a secondary vessel can be used with a primary only method, but it is then being used as a clearing tank. To do this, the brewer would allow the beer to attenuate and condition in the primary, then rack to a bright tank for a few days to further clear the beer. Often clarifies and/or cold crashing may be used to help clear the beer more quickly. So basically:
Primary Only Method 1. Allow beer to ferment and condition in primary 2-3 weeks
Primary and Secondary Method 1. Allow beer to attenuate 2/3-3/4 in the primary ~2-6 days
2. Rack to secondary
3. Allow to condition in secondary ~2-3 weeks A bright tank may be used with either method, though in most cases it is not needed when using a secondary fermentation schedule. I hope that helps to clear up some things.
Yeah man, thanks a bundle!
I'm currently dipping my toes into the homebrew experience, like the Jimmy Hendrix experience except... actually there are probably a lot of similarities, anyway, I digress.
I'm still waiting on my first kit, a dry one, and I was planning on a secondary fermentation. This has cleared up how to do it properly a whole lot!
I thought it was just to let the beer clear. Can't wait to see how it turns out!
It seems there is a lot of discussion arguing that 'secondary fermentation is a misnomer, it is clarification' and which method is best. I really liked your write up. I'm still unclear if I should use the first or second method. 3 days and the bubbles are slowing, foam has settled, thinking about racking to a secondary and dropping to 50 degrees for a few weeks.