Dear Homebrewit: Don't be in such a rush to rack to secondary!

I feel like 99% of the anxiety in the posts here boils down (har har) to: "I've had a beer in the primary for 6 days, can I rack to secondary yet??"

The "secondary" is where a secondary fermentation occurs, e.g. adding fruit, pumpkin, simple sugars after high krausen for metabolic reasons. It can also be where flavor additions such as dry-hopping or spicing can be done. It can also be where long-term clearing or lagering can be done. These are all perfectly acceptable uses for a secondary stage of fermentation.

It is not a substitute for an adequate primary fermentation. After the yeast has finished fermentation, it will begin to uptake fermentation precursors, especially acetaldehyde and diacetyl, which are two of the most common off-flavors in beer. The yeast can't bulk condition if you rack to secondary and leave most of the yeast behind.

Have patience. Let the yeast finish. Make better beer.

End of sermon. (Climbs down off soapbox.)

EDIT: Thanks to Pinot911 for pointing out that these compounds are not technically precursors, but intermediaries, in the production of ethanol.