So how long is too long?

I realize there has been a lot of talk the last handful of years about not needing to do a secondary fermentation and it seems to be settled that leaving the beer on the yeast for weeks on end seems to be the settled consensus.  I'm wondering though if a new threshold has been established.  For example, it used to be that a couple of weeks was all you wanted out of fear of autolysis (Sp?) but we all know beer can sit on the yeast much longer than that.  My question though, approximately how much longer than that is safe? 

thanks

WR

I have not heard of any, "threshhold".  Maybe it all comes down to how patient we are as individual brewers.

I remember basic brewing did some experiments a couple of years ago but the results were mixed and I haven't heard of anyone leaving their beer on the yeast for really extended periods of time to find out so who knows I guess?  I don't think I've ever had anything sit on the yeast longer than a month and I know that's just fine but I was wondering if say, 3 months is pushing the limit.  Of course, I primary in plastic so I wouldn't want the beer sitting that long on the primary anyway, not because of the yeast doing harmful things but because of the permeability of the plastic so I always move to glass after about 1.5 to two weeks (sometimes longer but not much). 

How long is not really the question.  When to remove from the primary  is the question.  The answer to how long is too long is any time after fermentation and dry hopping is complete.  That is, when you reach the target final gravity,any diacetyl rests ,and primary dry hop additions are done.  Most homebrew beers that is likely within 21 days. 

If you use a healthy fresh pitch of yeast, you can likely leave the beer on that yeast cake for 60 days without much affect though you will not know how much you can detect until you drink it.  There is more than yeast in there though.  You have other competing organisms and the breaking down of other compounds in the trub.  If you are at fermentation temps, then the new beer is oxidizing which will lead to off flavors.  Sure, this is not happening really fast at low O2 levels but it affects the life of the beer. 

My personal rule of thumb is 6 weeks... Unless I'm making something that needs a touch of oxidation.

But, like jomebrew... I'm typically 2 weeks in the primary. If it still needs clearing I will go up to a month. Beyond that, I use finings in a corny.

But why leave it so long?  Why not move it off the sediment, which contains more than just pure yeast, as soo as the yeast is done?  Why risk off flavors?  Why wait at all?  Why not get it into my mouth in the shortest time possible?  Isn't that why you brew?

the are practical answers to that question.  I have four plastic buckets that I primary in, four glass carboys that I secondary in, three kegs in the kegarator and two kegs in my lagering fridge, all of them are full.  For someone who doesn't drink much more than 2-3 pints in any given day (maybe more during football) it could take some time until I get some room in a secondary so the beer has to sit in the primary.  Add in a hectic schedule with two small kids and a lot of work to do, finding time and the room to get to the beer isn't always easy so the beer has to wait.  Of course, personally, I've never waited more than a month I don't think but I can see slower consumption rates leading to longer time in the primary.

Ahhh... a scheduling issue.  Since I re-use my yeast cake, I have to be more thoughtful in my planning.  I make sure that the beers are selected to flow easily from primary to secondary to keg, one after the other.  At times, when all 4 kegs are empty, I brew every weekend: primary for a week, secondary for a week, new beer in primary as previous moves to secondary, previous to secondary as previous previous moves to keg.  When all 4 kegs are scheduled to be full, I'm done.

As I drink them, when 1 keg gets empty, I start to plan the next run.  If I ws too energetic in brewing, I bottle a batch or two.