Pitching the yeast
Now that our beer has
been transferred to the fermenter, it is time
to add the yeast. The yeast we are using for
this brew is a Wyeast smack pack, which we
activated yesterday. We have sanitized the
yeast package in our iodophor sanitizing solution.
We'll use scissors to cut the corner of the
package open. We have sterilized the scissors
by holding the metal blades over an open flame
for about 30 seconds, being careful not to
burn our hands or melt the plastic handles.
Our yeast is pitched (added
to the unfermented wort) by carefully pouring
into the fermenter. We have checked to make
sure that the temperature of the wort in our
fermenter is between 65 and 75 oF,
and our yeast is at about the same temperature.
Yeast is a living organism,
and will not perform properly or will even
die if conditions are not right. If the temperature
is too low (under 60 oF for ales
and under 50 oF for lagers) the
yeast will be very sluggish or may not start
fermenting at all. If the temperature is too
high (over 80 oF) the yeast will
be killed and more yeast will have to be added
once the wort has cooled down.
If you are adding a different
type of yeast or using a yeast starter, the
process of pitching the yeast is pretty much
the same. A tube or vial should have a protective
plastic seal around the cap, which makes sanitizing
the container unnecessary. The vial or tube
should be shaken well before pitching.
Dry yeast should be rehydrated for the best
results, as covered in our yeast
A yeast starter can
be added directly to the fermenter as well. You
may want to sanitize the lip of the container
with the starter in it with a cotton swab dipped
in rubbing alcohol or a strong liquor (such as
vodka or rum) before pouring it in.
Aerating the Wort
have one more step before leaving
our brew to ferment.
We will aerate our
wort, or dissolve
oxygen into the wort, by shaking vigorously for
at least a minute. The yeast will need this oxygen
in this first stage of its life-cycle, the reproductive
stage. After the initial reproductive stage,
yeast becomes anaerobic, meaning it thrives in
an oxygen free environment. Thus, after your
beer starts to show visible signs of fermentation,
it should never be shaken or splashed. So just
before or after adding the yeast and before activity
is visible is the only time your wort should
Once the yeast is added to the fermenter,
it starts reproducing, because it now has a
huge new food source: 5 gallons of your hombrew!
During this reproductive stage there is no
visible activity, which is the reason for the
lag time between pitching the yeast and visible
fermentation. This lag time can range between
one and 48 hours, depending on many factors.
These factors include: quantity and freshness
of the yeast, amount of available dissolved
oxygen, temperature of the wort, concentration
of sugars in the wort (a stronger beer will
take longer to start fermenting), and the type
of yeast (lager yeast's generally take longer
than ale yeast's).
Now it's time to ferment!