Primary only vs secondary = effect of yeast clean up

I have been doing some reading and asked some questions on primary only vs using secondary. I know there's a lot of differences in opinion on this matter. Which has made me think the real main differences (depending on what style of beer) Is that it will change the taste and clarity. But now Im asking my self how does it effect the clean up the yeast do after the main conversion of starch's of sugars are complete. I know it is important to let them finish there job , but how does it effect that process using a primary only vs secondary also. There has to be a difference do to the fact that there most likely is more yeast if left in primary only. But its full of mostly dead cells. The lively cells are still suspended , right? I know this might be a stupid question but im new to brewing and think about things like this a lot.

First of all, no question is stupid! I do extract brews mostly and only do primary for simplicity's sake. Primary only is not a bad way to go. The difference comes in aging. As you may know, you don't want the dead yeast cells and other sediment to stay in your beer longer than two weeks. They break down and cause off flavors. Most ales will be completely done fermenting within 10 days. But, especially in higher gravity beers, they can take longer to ferment and there is benefit in aging. I think it's mostly about the chemical compounds that result from all that sugar being changed into alcohol that have to precipitate or something. Although, someone else may need to weigh in, because I am not sure what is the advantage over bottle or keg aging. Doesn't the same thing happen there?

Jonives said:

As you may know, you don't want the dead yeast cells and other sediment to stay in your beer longer than two weeks. They break down and cause off flavors.

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I hate to contradict, but that's not at all accurate. The idea of not allowing beer to sit atop the yeast cake for over 2 weeks comes from commercial brewing using large conical fermenters and does not apply to home brewers using carboys/buckets. You'll be perfectly fine running your fermentation in the primary for 3-4 weeks. Important to the whole process is temp control. Mid-60's is best for most ales.

Jonives said:

Most ales will be completely done fermenting within 10 days.

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Mostly done? Sure. Completely done meaning the yeast has finished cleaning up after itself and the FG has stabilized? Maybe or maybe not. The only way to know for sure is to take consecutive hydrometer readings. Otherwise, let it ride 3 weeks in the primary and then bottle.

There are three of phases of fermentation. At the beginning, the lag phases is when you add the yeast and it seems nothing is happening. That is when the yeast are reproducing and fermentation will start. Fermentation is the next phase, and when that finishes up, the conditioning will start.

When the beer is done fermenting, the yeast will still be active and scrounging around for food. Once the easily digested maltose is gone, the yeast will work on less preferred foods, including their own waste products (like diacetyl). That's what most people are referring to when they say "the yeast cleaning up after itself". After that, the yeast will flocculate and fall to the bottom.

These phases aren't all isolated, as they overlap, so even though it seems like nothing is happening there is still some activity in the fermenter.

The yeast doing the "work" are in suspension, so it really doesn't matter if there is a layer of trub on the bottom or not. That is, moving the beer to a clearing vessel won't hurt, but there is nothing magical about it either. The beer will still do their thing whether in the primary or in the clearing vessel.

The beer will still clear just fine in the primary, and any autolysis (the off flavors from spent yeast) isn't an issue in the 1-3 weeks (or even more) that the beer will spend in the fermenter.

From my experience, leaving beer in primary for however long does not negatively impact it, I went three months once and I've found that leaving the beer on the cake cleans it up. The yeast on the bottom has simply fallen out of suspension, it isn't doing much but it isn't necessarily dead. I routinely harvest this yeast to repitch or to make a starter so I'm confident that they are indeed alive. I think the bad flavors from dead yeast is am old wives tale. If it does happen I think it is more likely due to pitching a bad yeast than to leaving it on the cake too long.
I don't usually secondary and my beers a they are typically adequately clear. I do extended primaries and haven't had any I'll consequences.

captwalt said:

From my experience, leaving beer in primary for however long does not negatively impact it, I went three months once and I've found that leaving the beer on the cake cleans it up. The yeast on the bottom has simply fallen out of suspension, it isn't doing much but it isn't necessarily dead. I routinely harvest this yeast to repitch or to make a starter so I'm confident that they are indeed alive. I think the bad flavors from dead yeast is am old wives tale. If it does happen I think it is more likely due to pitching a bad yeast than to leaving it on the cake too long.
I don't usually secondary and my beers a they are typically adequately clear. I do extended primaries and haven't had any I'll consequences.

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I have found that while it may not "negatively" impact it, that there are taste differences between a shorter (say, 7-14 days) and a longer (three weeks +) primary. I prefer the shorter time for my taste, but many others prefer the longer primary.

There was a podcast on Basic Brewing Radio about a year or two ago that did this as an experiment. They made the same beer in a variety of ways- tradition primary/secondary, a long primary, etc. While all noticed differences in the finished beer, the testers were split on which they preferred!

I'd suggest to anybody to try it themselves. See which they like better. For me, I don't leave beers in the fermenter for more than about two weeks on purpose but it does happen due to life events. My preference is to package the beer around 2 weeks for most ales.

"That is, moving the beer to a clearing vessel won't hurt, but there is nothing magical about it either." Yooper.

Oh, Yooper, I could not disagree with you more!! It is an epic experience to watch the golden, amber, chocolate, etc. heavenly liquid cascade through the racking tube. It is a wonderful bonding moment with your beer that only serves to heighten the anticipation for when one can finally achieve oneness with your creation. It is magical indeed....

I leave mine in the PV 3-4 weeks and then bottle and condition for 2 months
I will even bulk prime the PV and then lightly stir wait an hour then bottle
I have NO PROBLEM with clarity either. People can say what they want but this does work.

It's important to understand the yeast that settles to the bottom isn't dead, it's dormant. If it were dead none of us would even have this hobby and the world be a sad place indeed! Only in extended periods, months not weeks, do yeast begin to actually die and decay (autolysis). If fear of this is your reason for secondary, you're on a fools errand. The debate lies in the issue of clarity, and even this doesn't show "clear" evidence of improving any faster in a secondary versus a single vessel ferment. If you can transfer in a sanitary way and guarantee no oxidation, knock yourself out. This is pretty difficult to do for most home brewers using buckets and/or carboys though which is why I so highly advocate primary only for any beer that will be done in less than 2 months...

While some taste tests liked beer racked to secondary, and all taste is a matter of opinion- for yeast to fully metabolize out the bad flavors (diacetyl) takes time, racking to secondary in 2 weeks shortens this life. Plus, you have an increased chance of infection, however slight. This flavor enhancement is most noticeable in lagers, which can be lagered for months (though truly, when you go < 40 degrees, this isn't yeast working, as even lager yeast goes to sleep at that temp).

There were scientific tests of wine a number of years ago, and many tasters gave very high ratings to brett infected wines (Which unlike beers, brett is always bad in wine). So, the tasters rated them highly, but "technically" they were infected / bad wines.

In the end, it is all a matter of taste. Most brewers hate cleaning the most- so why put into secondary and increase this workload? That is, unless your ageing (in which case you want to minimize yeast / trub) or adding something for flavoring.

I read some secondary vs primary only tasting notes on a few threads. Some beers showed a slight taste advantage to the 2-stage beers, others showed the single tasted better. The results were far from conclusive, and I think demonstrate (for me at least) no big advantage to the transfer. I didn't even transfer my 11% abv barley wine 2 years ago and the last bottle I had a month ago was great. For me the risk of oxidation during the transfer was way more important to avoid than any worry of a long primary. I went about 6 weeks primary on this one then strait to 22oz bottles. Again, I'm VERY happy with the result.
I know this is a hot topic on this forum, but if you are a newer brewer you really should consider the risk vs reward ratio of anything you do in your process. The rewards of 2-stage fermenting are minimal at best on ales (I don't even transfer my lagers), but the risk of oxidation is very real. Unless you have a system to transfer beer in a zero oxygen environment, you're really taking an unnecessary risk...

For most styles a longer primary and no secondary will be perfectly fine, and that is typically what I do. If you're not pitching enough healthy yeast and/or fermentation temps are not well-controlled, a long primary can definitely help clean up undesirable off-flavors.

However, I've also found that too long in primary can clean up and remove desired flavors in certain styles. There's a reason Belgians and Hefes typically have very short primary times. Leave those styles on the yeast too long and you'll find the clove you were expecting just isn't there.

So, skip the secondary if that makes sense for you, but if you want to make the best beer possible, pitch the proper amount of yeast and control your ferm temps so that undesirable off-flavors are avoided in the first place. Doing so gives you options that you otherwise may not have.

LLBeanJ said:

There's a reason Belgians and Hefes typically have very short primary times. Leave those styles on the yeast too long and you'll find the clove you were expecting just isn't there.

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This is a great point. I usually do 3 weeks or so, but i've also had super fast ferments with big healthy yeast pitches and O2. I'm starting to leave it in primary only as long as it takes to get a few days with stable gravity reading and no longer. This is with my Belgians only as they are so yeast driven in taste and aroma.

I used WLP565 and did everything perfect, but I think I left it in too long and it cleaned up some of the good stuff. Its still excellent though.

LLBeanJ said:

For most styles a longer primary and no secondary will be perfectly fine, and that is typically what I do. If you're not pitching enough healthy yeast and/or fermentation temps are not well-controlled, a long primary can definitely help clean up undesirable off-flavors.

However, I've also found that too long in primary can clean up and remove desired flavors in certain styles. There's a reason Belgians and Hefes typically have very short primary times. Leave those styles on the yeast too long and you'll find the clove you were expecting just isn't there.

So, skip the secondary if that makes sense for you, but if you want to make the best beer possible, pitch the proper amount of yeast and control your ferm temps so that undesirable off-flavors are avoided in the first place. Doing so gives you options that you otherwise may not have.

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Can you explain to me how racking a beer to a secondary removes the yeast in suspension in the beer? What prevents the suspended yeast from removing the "desired flavors", Magic?

Lagering.

I recently picked up a copy of "Brew Like a Monk" as I was interested in how to get better yeast flavor from my Belgians. While the different Trappist breweries have varying pitch rates and fermentation temps and times, one of the constants was a quick primary (5-7 days was pretty common), followed by transfer to secondary for lagering at cold temps (ranging from 32f to 50f) for anywhere from 2 to 4 weeks to crash the yeast so that fermentation is halted.

Belgians also benefit from a gradual rise in fermentation temperature. The typical mid-60s for ales mantra will subdue their character. I brew quite a few Belgians and just bottle or keg a week after stable final gravity. Never had an issue with them "cleaning up the good stuff"...

Yooper said:

There are three of phases of fermentation. At the beginning, the lag phases is when you add the yeast and it seems nothing is happening. That is when the yeast are reproducing and fermentation will start. Fermentation is the next phase, and when that finishes up, the conditioning will start.

When the beer is done fermenting, the yeast will still be active and scrounging around for food. Once the easily digested maltose is gone, the yeast will work on less preferred foods, including their own waste products (like diacetyl). That's what most people are referring to when they say "the yeast cleaning up after itself". After that, the yeast will flocculate and fall to the bottom.

These phases aren't all isolated, as they overlap, so even though it seems like nothing is happening there is still some activity in the fermenter.

The yeast doing the "work" are in suspension, so it really doesn't matter if there is a layer of trub on the bottom or not. That is, moving the beer to a clearing vessel won't hurt, but there is nothing magical about it either. The beer will still do their thing whether in the primary or in the clearing vessel.

The beer will still clear just fine in the primary, and any autolysis (the off flavors from spent yeast) isn't an issue in the 1-3 weeks (or even more) that the beer will spend in the fermenter.

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Great! Makes total sense to me! What doesn't mesh for me is this: why is there any advantage to having this process of cleaning up happen in the fermenter. When u rack to your bottles or your keg, isn't there yeast in suspension? Isn't the cleanup and clearing happening there as well? Since the yeast cells in the cake are dormant, why leave the beer on the yeast cake?

Jonives said:

Great! Makes total sense to me! What doesn't mesh for me is this: why is there any advantage to having this process of cleaning up happen in the fermenter. When u rack to your bottles or your keg, isn't there yeast in suspension? Isn't the cleanup and clearing happening there as well? Since the yeast cells in the cake are dormant, why leave the beer on the yeast cake?

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Good question. There are indeed still yeast in suspension, but only a fraction of what's in the cake. It's the yeast that are settling into dormancy that are absorbing potential off flavor compounds. Leaving the beer on the settled yeast is convenient, maximizes their chance to "clean up", and reduces exposure to oxygen in an unnecessary transfer. Exposure to oxygen post ferment reduces flavor stability, and in extreme cases can ruin a batch. Unless of course you like the flavor of wet cardboard!

I have been brewing for over a decade and have always used a secondary. I have not once produced a beer that has the flavor of wet cardbord, not even a slight flavor. The amount of oxygen the is introduced by transferring is usually small if you are careful.

Jonas217 said:

I have been brewing for over a decade and have always used a secondary. I have not once produced a beer that has the flavor of wet cardbord, not even a slight flavor. The amount of oxygen the is introduced by transferring is usually small if you are careful.

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I don't doubt you have. I'm not saying you or anyone who uses a secondary is wrong. I'm just saying it isn't a NECESSARY step, and newer brewers can benefit by a simpler process. In fact, I doubt any brewer really LIKES the process of cleaning, sanitizing and transferring to a second vessel. For me, I have a very finite amount of time to spend on brewing, and I choose not to spend it "racking" as I've actually observed an INCREASE in the quality of my beer since abandoning the practice 2 years ago...

retread2 said:

Can you explain to me how racking a beer to a secondary removes the yeast in suspension in the beer?

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it doesn't

What prevents the suspended yeast from removing the "desired flavors", Magic?

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absolutely nothing.