As your yeast settles into its warm and sugary new home, it will begin
to feed, converting sugars to alcohol and carbon dioxide (among other
trace compounds that contribute to beer's flavor and body). This
production of gas requires an outlet lest the fermenter should blow
its lid, and as fermentation kicks into high gear, the gas will escape
through the bubbling airlock. This is a handy way of viewing the
progress of your beer's fermentation, and you should check the airlock
daily to see the rate at which bubbles are escaping.
When the rate
slows to one bubble every 90 seconds or so, which can happen in as few
as three days (in warm temperatures) or as many as ten days (in cooler
temperatures), fermentation is just about complete and your yeast will
begin to autolyze or feed off one another (producing odd flavors) if
you do not transfer your beer to your secondary fermenter within 2-3
days.
Racking your beer (estimated time: 45 minutes)
Recklessly exposing your beer to air is an easy way to cause
contamination, especially if the beer is agitated to the point where
it sloshes or produces bubbles. How then should one transfer 5 gallons
of maturing beer from one vessel to another, and without transferring
dead yeast or other sediment? The answer is a process called racking.
When you are ready to move your beer from one fermenter to another,
sterilize and air-dry your rubber tubing and racking cane. Connect the
tubing to the end of the racking cane's elbow joint.
Take your primary
fermenter and, taking care not to slosh you beer, place it on a
counter or other stable, high surface, and place your secondary
fermenter (whether glass carboy or second plastic fermenter) on the
floor. Carefully open the fermenter and slide the lid just enough to
provide space for your racking cane, and slide the cane into the beer
so that it is well below the surface but not sitting in the yeast
sediment at the bottom.
It is important to keep your beer as covered
as possible at all times to prevent contamination by air particles.
Rest the other end of the tubing at the bottom of the secondary
fermenter and pump the racking cane a few times to get the beer
flowing through the tube.
Continue pumping until you have a continuous stream of beer with no
bubbles, then gravity will do the rest. Tip the primary fermenter as
the level drops to ensure the nose of the racking cane never dips into
the yeast, and once you have transferred all you can, pull the racking
cane out of the beer, remove the tube from the secondary fermenter and
transfer your airlock from one vessel to the other (if you are using a
second plastic fermenter, you'll want to firmly affix the lid on
before moving the airlock).
Place your secondary fermenter where your primary used to be, and let
fermentation continue for another few days. You may continue to notice
very slow bubbles through the airlock, but if you don't, not to worry.
The beer can remain in this state for up to a week (depending on
temperature), but after about 3-4 days, your beer should be ready for
bottling.