Expert: Keith Patton - 11/23/2008

Question
when should I transfer beer to second fermentation after bubbles completly stop or before?

Answer
There are mixed opinions on it.  If you are a relative beginner, and you only have one carboy, and have to use an intermediate container, transferring or racking the beer before it ferments out is just another risk of contamination. The beer in in a protective blanket of CO2 in a positively charged vessel.  Most advanced home brewers that rack early while the beer is still fermenting have a CO2 cylinder and will first purge the second carboy with CO2 to drive out the O2.  Then rack it to the second carboy where it will it will sit under the new blanket of CO2.

Alternatively if the beer is actively fermenting it will generate a new blanket of CO2, but why bother?

The main reason to rack is to get the beer off the dead yeast before it starts to break down and possibly give off flavors to the beer.

If you don't have good temperature control,(e.g. a lagering refrigerator with external thermostat) this might happen at higher temperatures, but I wouldn't worry too much about it.

So I would wait till the beer is completely fermented out.  Rack it if you must, then clarify and then bottle it.