Originally Posted by TeleTwanger

Here's what Noonan says about racking:

"Employing up to 5 percent strongly fermenting kraeusen beer at racking produces a stronger start of secondary fermentation and a better overall fermentation. This absolutely must be done when yeast performance during primary fermentation has been poor, as it replenishes the degraded culture."

"Racking must be done without rousing or splashing to prevent oxygen from entering the solution"

Originally Posted by billtzk

It's funny how trends change over time.

In the not too distant past, many brewers aspired to fly sparge to get the best yields from their grains; now most brewers (judging by responses on this board, anyway) prefer batch sparging and some even claim it gives better yields than fly sparging.

Not too long ago, the most sound and sage recommendation from experienced brewers to newbies was to get your beer off the trub and into a "conditioning" vessel (it's not for secondary fermentation, they'd say) as quickly as possible after fermentation stops to avoid autolysis (cannibal yeasties eating their own), and to give the beer time to clear and let sediment fall out. Now many brewers seem to skip the conditioning altogether, and go straight to the keg or bottle from a long, three to four week primary. Occasionally you even hear from some brewers that they let their beer remain in primary for absurdly long times, up to 12 weeks. A couple of years ago on this board you'd have been told to dump it if it was on the cake that long.

My change from batch sparging to fly sparging has brought me a 16% improvement in efficiency, so I think I'll stick with fly sparging. I still get my beer off the trub and yeast cake within two weeks, and then condition my beer in another vessel for several weeks before bottling. I think my beer is much improved by that process although I haven't done any comparison testing.

Originally Posted by BarleyWater

This "secondary fermentation" is the process of bottle conditioning or krausening, creating a small fermentation in the bottles/cask to get carbonation. It is not refering to anything that most homebrewers think of as a "secondary".

Most homebrewing pratices are taken from commercial breweries and scaled down. Since we don't have the need to move as much beer through our production lines as possible, we don't need to empty out the fermenter. The only reason that conditioning tanks exist is to allow for the production of more beer. That said, I only use a conditioning tank for long conditioning such as lagers so I can free up my primary, or when dry hopping because yeast can cause hop oils to precipitate out of solution. Otherwise, no conditioning tank neccesary.

Originally Posted by TeleTwanger

Noonan is specifically talking about lagers but the idea for Ales is the same and he's not referring to bottling or casking but secondary that homebrewers use:
"The purpose of racking is to seperate the beer from decaying yeast cells and flavor impairing precipitates. Care must be taken that no yeast sediment or trub is carried along into the secondary fermentation....Cone-bottomed "unitank" fermenters preclude the necessity for racking to a secondary/lagering tank. Trub is discharged from the bottom outlet throughout the course of primary fermentation."

He then goes on to describe lagering, terminal gravity, fining, and finally casking and/or bottling.

Originally Posted by BarleyWater

I haven't read the book myself, but tell me, why on earth would anyone add 5% actively fermenting beer to their conditioning tank. And why would this matter... ...if you are just going to add more yeast back in the 5%.

The process of krausening is well documented, and is for the production of bottle and cask conditioned beers in order to get carbonation.