Temp after initial ferment completes?

What are you trying to accomplish with “want to let it sit in the fermenter for another couple weeks”?

If you are looking for additional conditioning from the yeast (e.g., have the yeast ‘clean up’ compounds (e.g., acetaldehyde, diacetyl, etc.) created during the primary ferment) then you want to keep the fermenter at warm temperatures; this will permit the yeast to be active.

If you are looking to ‘drop out’ stuff like polyphenols, proteins, and the yeast then conditioning at colder temperatures (e.g., 50°F) is appropriate.

Cheers!

 

They are talking about letting the yeast clean up their byproducts. You need to keep the yeast at or near fermentation temps for them to do that effectively. Tasting a sample will tell you how that is coming along.

 

Most beers will benefit from lower temps rather than higher ones when fermenting...you will get less of the 'HUGE hangover' fusel alcohols, strange esters and other nasties which make the beer taste worse,..letting the beer sit in the fermenter for a few weeks wont do it any harm (assuming its not too warm!)....but it wont achieve much either tbh.....the real danger you may get if left for too long on the yeast cake is yeast autolysis which produces off flavours...but that usually only happens if the fermented beer/primary fermenter is far too warm!

 

The benefits of the cleanup of typical fermentation byproducts that will happen in the fermenter during a week or two post fermentation far outweigh the nearly nonexistent risk of autolysis.

 

Yes some homebrewers maintain it can help slightly under certain conditions but its not quite as clear cut as some like to make out or claim...and i have never noticed any significant gains personally by leaving fermented beer to sit on its yeast cake.....

There's still a lot of controversy within the home-brewing community on the value of racking beers, some do it some dont...some even like to leave their beers sitting on the thick sediment for a few weeks claiming the yeast will 'clean-up' certain by products of fermentation..yet many seasoned homebrewers have declared that there is no real taste benefit in doing this at all.

Yes the yeast may clean up some of the by products they produced during the faster paced primary phase. But this 'clean-up' stage can sometimes have its own drawbacks too!

Under certain conditions, the yeast can also metabolise some of these compounds in the trub. The "fermentation" of these compounds themselves can ALSO produce several of their own off-flavors!

Plus dormant yeast on the bottom of the fermentation vessel can also start to excrete amino and fatty acids! Leaving the beer on the yeast cake and trub for too long (say more than 2-3weeks) can sometimes result in soapy off flavors becoming more evident...

Autolysis is only really an issue if beer is left on its cake for too long and at too high a temp...but its still a risk.

For these reasons, i prefer to get the beer off of the trub and dormant yeast pretty well as soon as the beer has cleared...leaving it any longer in my personal experience contributes little if anything.

If you brew at the right (slower and cooler!) temps you shouldn't get too many fermentation by-products anyway...

Home brewing is a very subjective experience..and like most hobbies opinions and ideas will vary considerably...

 

No, I maintain that it can help greatly, under normal conditions with healthy yeast. Fermentation, including the conditioning/cleanup phase, happens in phases. There is some overlap, but it's inescapable that the reduction of byproducts continues after attenuation is complete.

Also, our understanding of what's happening from a practical standpoint has advanced somewhat since the words you paraphrased from How to Brew were written.

 

You're mixing too groups of bad advice together to create a lot of bad information.

There's one camp, the bad advice of the mid-2000s forward, that you need to leave your beer on the cake for a million weeks because that's the only way it tastes good, especially if you won't wait six years in the bottle for the beer to carbonate. That advice tends to be ok, even mostly true, if you have bad brewing technique. If you are treating your yeast poorly, then yes, you have a lot of off flavors that need to get cleaned up and time will usually take care of that. This camp has grown strong because it has particularly boarish champions who shove that advice down new brewers' throats and since they usually don't have great technique they believe it to be true when their underpitched beers are better at three months instead of a month because the yeast cleaned up after themselves. Then they regurgitate the same nonsense.

The other camp is the older group that fear autolysis and all the stuff you talk about with amino acids, etc. Autolysis occurs but at the homebrew level the pressure and heat isn't present in our fermentors to cause that stuff to happen. At larger, commercial scale systems, it is a relevant concern. It used to be absolute certainty among homebrewers that if your beer touched the cake for more than seven days -- to the minute -- your beer would taste like beef broth. That, obviously is not true. Not even at the commercial level.

You're shuffling both together and declaring there is no clear answer. While I agree homebrewing is a subjective experience, the science of how yeast operate is not subjective in the least. For most ales (excluding sour/funky beers, relatively high ABV beers, lagers, certain yeast strains like Dupont), if your technique is good you really only need 1-2 weeks in the fermentor and 1-2 weeks of conditioning in the package. The yeast will clean up byproducts whether they are in secondary, primary or a bottle. Obviously if you are lagering the beer to drop out the majority of yeast you want to make sure the clean up occurs beforehand as a precaution or if you filter you want to have clean up complete prior to filtering. Same is true if you keg and go right into the cold after force carbonating.

 

As long as you don't drop to lagering temperatures or filter the beer, you'll still have plenty of yeast in suspension to clean up fermentation byproducts. The cake of yeast at the bottom should have zero impact on any of that.

Only time I rack a beer off the yeast cake is when I want to pitch that yeast into a fresh batch of wort

 

Exactly.....good point!....and as i said in my above post ''For these reasons, i prefer to get the beer off of the trub and dormant yeast pretty well as soon as the beer has cleared...leaving it any longer in my personal experience contributes little if anything.''

My advice to any homebrewer is TRY all the different ideas and approaches yourself and then see what works best for you, some excellent points made by all the members here, but as always its 6 to one and a half a dozen to another!.....homebrewing is very often a personal and subjective experience....

 

O.P. - When I ferment, I usually keep the temp around 65-68 depending on what is being brewed. This usually takes a week or two (average). When I "warm up" the beer, I take it out of my swamp cooler and let it warm to about 70-73 deg. All you need is a couple degrees, just to keep the yeast a bit more active in an environment that has become less hospitable. If, after a couple of weeks at the higher temp, you would like to "cold crash" you beer (for reasons listed above), this is done at much lower temperatures. You will likely need some type of refrigeration to cold crash, but I rarely do it as I feel it is mostly for clarification. After approx 4 weeks in the fermenter my beers are usually very clear.

 

For big beers I've been pitching under the recommended temp by 2-8 degrees. At about 2 days I'm at the lowest recommended temp. At three days I let it warm up and day four I'm above the window. And my fermentation is about complete (by the numbers). I've been finishing WLP007 at 74-75 and it sits there for two weeks. I've shared these beers with club members and no issues. I've read that all of the off flavors come early and I'm a believer.

Now I do whirlpool and let the trub drop out for 30 minutes, and I do a slow transfer. I also pitch active yeast. For big beers about 1.4x and oxygenate twice.

Then I cold crash and keg.