Secondary fermentation & the role of yeast

[Grizybaer]

So I understand that primary fermentation is
Sweet wort + yeast = dry wort + alcohol + co2 + yeast trub

For 2nd fermentation,we rack off the liquids and leave the yeast cake behind.
Doesn't the yeast play an important role in conditioning the beer. For example, doesn't bud add beechwood chips to increase the surface area to which the yeast can stick, increasing its exposure to the beer?

So my question is why do we even transfer to the 2nd fermenter. Shouldn't we just leave it in the primary and shake things up to agitate the yeast provided that the system is closed and not in contact with oxygen. Back in the day didn't they do this by periodically rolling kegs?


Thanks in advance for the insight.

 

[drhookmec]

There has been much debate on this here.
But you are correct the secondary fermentor isn't needed unless your
planning on dry hoping or add some sort flavoring such as oak chips etc.

A lot of brewers on here including me have good luck going with longer primary's
and skipping the secondary.

 

[gypsyhead]

You're right on a lot of points, but just to clarify, Bud mostly uses the beechwood to increase surface area so they can speed up the fermentation process so they can keep pumping out brew, not necessarily for flavor (not that you suggested that, just gets a lot of folks confused).

I'd say take a listen to the Brewing Network's Brew Strong shows on Yeast Washing and Fermentors (available as a podcast on iTunes or through thebrewingnetwork.com). They talk about primary and secondary vessels, why you would use one or the other, when you need a secondary, etc.

Essentially, you probably only need a secondary if you'll be long aging because if you let the brew sit on dead yeast for too long, it'll begin to autolyze (sp?), creating off flavors that you don't want. If you're doing a standard brew like an APA or IPA, the only reason to rack to a secondary would be if you're dry-hopping and are worried about the hops sinking into the trub and being inactivated, (though there's plenty of evidence dry-hopping still works in primary).

 

[Captain Damage]

For example, doesn't bud add beechwood chips to increase the surface area to which the yeast can stick, increasing its exposure to the beer?

Don't assume that because Budweiser or some other commercial brewery does something that it's a good idea for homebrewers to try and mimic it. Commercial brewers deal with conditions largely alien to homebrewers, not the least of which is that economic considerations underpin just about everything they do. E.g., when a commercial brewer gets beer off the yeast yeast and into a bright tank (secondary fermenter), it's mostly so they can harvest and reuse the yeast and move a new batch of beer into the fermenter as soon as possible to maximize production. A fermenter that's not fermenting is wasting money.

 

[usfmikeb]

Back when I started brewing, everyone thought you had to bet the beer off the yeast cake after fermentation was complete, or autolysis would occur. Autolysis is essentially yeast cannibalism, and was said to contribute off flavors. However, this is mostly thought to be false at this point.

Typically, I usually tend to leave my beers in primary for a month now, and only secondary when adding fruit, dry hopping, or long term bulk aging.

 

[Strangelove]

Here's my understanding:

There's no "secondary fermentation". Once it's fermented, it's fermented. The yeast can clean up various secondary products of fermentation, though. The secondary is for clarity or to add things, (fruit, dry hopping. etc).

The yeast will always be there. I keeps working in the secondary and in the bottle despite leaving the cake behind.

The reason that secondaries were popular for a long time in home brewing is autolysis (cell death). Poor quality yeast would die and add off tastes. This is no longer an issue unless you're a commercial brewer with gigantically tall fermenters. The large PSI from the column of beer can cause autolysis, even with good yeast.

 

[Nathan666]

Hi there (quite new to brewing) just a lil question on this subject you say only really use secondary for dry hopping adding fruit etc what do you mean by fruit( for example could I cut up some orange and drop it in, in secondary to add to flavour or what?) I don't completely understand this maybe a stupid question? Thanks

 

[usfmikeb]

One of the beers that I make a few times a year is a Raspberry Wheat, and I'll throw the raspberry puree into the secondary and rack on top of it. I also make some beers with cherries or strawberries and do the same thing.

 

[Strangelove]

I hate to be "that" guy, but the search function is your friend:

https://www.homebrewtalk.com/search.php?searchid=11787210

117 threads specifically about adding fruit.

 

[Grizybaer]

Well, I'm not taking about adding fruit, I'm talking about the role of yeast in beer conditioning. It seems like the general concensus is that all fermentation and conditioning happens during primary fermentation and the secondary is for addition of flavors or dry hopping . I ask because some beers seems to get better with time and I'm wondering what the mechanism is for this change in flavor profile. I thought it was a function of contact with yeast

 

[shawnbou]

Well, I'm not taking about adding fruit, I'm talking about the role of yeast in beer conditioning. It seems like the general concensus is that all fermentation and conditioning happens during primary fermentation and the secondary is for addition of flavors or dry hopping . I ask because some beers seems to get better with time and I'm wondering what the mechanism is for this change in flavor profile. I thought it was a function of contact with yeast

That is correct, to my knowledge. A lot goes on in the process we call "conditioning", but from my understanding the main factors are activity of the yeast in the beer and other chemical compounds (such as oxygen).

Keep in mind that even when you rack beer out of the primary, there is still some yeast in suspension unless you are filtering, pasteurizing or otherwise killing them. That's why you can still naturally carbonate a beer that has sat in a carboy for a very long time. That also allows for some limited "conditioning" activity even after a beer has been racked.

However, it seems the more yeast the beer is in contact with, the better (up to a point). Thus the school of thought that now has a lot of us doing long primaries to get great results.

 

[Grizybaer]

That is correct, to my knowledge. A lot goes on in the process we call "conditioning", but from my understanding the main factors are activity of the yeast in the beer and other chemical compounds (such as oxygen).

Keep in mind that even when you rack beer out of the primary, there is still some yeast in suspension unless you are filtering, pasteurizing or otherwise killing them. That's why you can still naturally carbonate a beer that has sat in a carboy for a very long time. That also allows for some limited "conditioning" activity even after a beer has been racked.

However, it seems the more yeast the beer is in contact with, the better (up to a point). Thus the school of thought that now has a lot of us doing long primaries to get great results.

Good to know, I started fermenting in kegs and have been rousing the yeast by shaking or rolling. Just wanted to check hat I wasn't doing more harm than good. Thanks for the insight

 

[ReverseApacheMaster]

The "secondary fermentation" term is generally a misnomer. A secondary fermentation would only occur if you racked out of primary before primary fermentation ends or you rack to a second vessel and add more fermentables or something that can ferment what the yeast did not (such as brett or bacteria). The more appropriate terminology for the second vessel used to take the beer off the trub would be a bright tank/conditioning tank/etc. since there's generally no more fermentation going on. I guess it would be appropriately called a secondary vessel though...