Determine ideal lag time?

[ShootsNRoots]

Over/under pitching doesn't make the ideal beer. Instead we use computators and calculators to whiz bang some number for the yeast cell count and starter size etc..., etc.... in an effort to get the ideal number of yeast cells.

Now, lag time is the phase when the yeast grows and multiplies enough to ferment your wort.

If their is no lag or there is too long of a lag, then you know you overpitched/underpitched (goes hand and hand with aeration) with possible side effects to beer.

Now my question is, how do you determine the ideal lag time? I always see statement like 'Pitched starter and was fermenting in 4 hrs?'. Great! but is that too short or too long of a lag time? or 'Pitched one vial and no activity for 36 hrs but then it took off..." is that too long a lag time?

How does one define the ideal lag time for a given fermentation? In which scenarios is lag time a good or bad thing?

 

[stpug]

Chris White defines the lag period as 3-12 hours after pitching (based on a PDF I once read and for the life of me cannot refind!!!). I'd use that as a good "rule of thumb" to go by.

IIRC, lag phase is partly responsible for reproduction but more importantly is when the yeast uptake the available nutrients and oxygen in order to reproduce, perform, and finish up. I believe the bulk of reproduction still takes place in the (wait for it) exponential growth phase

Temperature is also going affect lag phase (too cold = longer lag, too warm = shorter lag).

A reasonable amount of lag time should always be a good thing, as long as it's not too long .

 

[SpeedYellow]

The "best" lag time will also have to consider ale versus lager. Pitching 38F yeast from the fridge into 48F wort may give longer lag times than pitching active 68f yeast into 68F wort. I'm not sure, because I've never considered lag time to be worth monitoring.

 

[LeroyLedbetter]

I'm a new all grain brewer who just brewed my first all grain the other day. I know my lag time was too long but I also know why it happenes. I had a conglomeration of many factors that contributed to it including underpitching, pitching too warm, and not aerating. I am interested in seeing resp ok nses to this post to better understand this process.

 

[stpug]

You can get a better description of yeast phases by reading this:
http://www.sicilianosmkt.com/v/market/resources/Beer-Understanding-Yeast.pdf

Edit:
This thread sparked me to re-find what had been lost and I did!! I guess the original pdf document has been removed from whitelabs.com but there's still a remnant of it floating here:
http://www.scribd.com/doc/152401169/Yeast-Life-Cycle-pdf