Yeast is one of the most important parts of the fermentation
process - it gives the beer alcohol, of course, but more importantly
it contributes to the flavor. Dry yeast has a certain level of
contamination from bacteria that will get into the flavor profile
of your beer. That's why using liquid yeast is the first step
toward better beers, it is a pure culture of a certain type of
yeast. Some beers require specific yeast to give certain flavors,
such as, Bavarian weizen needs a clove flavor, Trappest ales need
a banana flavor. You can tell during tastings which beers were
made with liquid yeast because of the clean flavor compared to
dry yeast. I think brewers stay away from liquid yeast because
they think that it is difficult to use - this is just not true.
It does require that you plan your brewing session a few days
in advance but that is about it.
To use liquid yeast, first look on the packet for the date stamp.
That will tell you how many days before you brew that you will
need to burst the inner pack. Allow one day for each month past
the date stamp plus one extra day for the culture to incubate.
You can tell that the yeast is growing by the package growing.
If the package grows so fast that it is ready before you are,
put it in the refrigerator, this will slow the growth and give
you some extra time.
When the package is ready, you have to options: pitch the yeast
that is in the package, or make a starter. Pitching the yeast
in the package is risky, there isn't enough yeast to start fermentation
quickly enough to safely prevent infection. I have tried this
and there was a lag time of about 24 hours - way too long for
me to risk infection and having to throw out a batch that took
6 hours to brew.
Making a starter is far safer because you will pitch many times
more yeast. You need to allow one extra day before your brewing
session for the starter to be ready. Basicly, a starter is a small
beer. First, sanitize your equipment - the yeast packet, an airlock
and stopper, a small funnel, and a bottle large enough to hold
the size starter you plan to make Add one Tablespoon of dry malt
for each cup of water. I like to make a 1 quart starter, so I
add 4 T to 4 cups of water and bring it to a boil. I add a few
hop pellets to acidify the wort and prevent bacterial growth.
You can also add some yeast nutrient if you wish. Boil for 15
min., cover, and force cool. Pour the wort into your bottle, try
to leave behind as much trub and hops as you can. Shake the packet
to introduce oxygen, tear it open and pour it into the wort. Attach
the stopper and airlock.
Allow 18 to 24 hours for the starter to reach high krauesen before
pitching. Swirl the starter to suspend all the yeast and pitch
the whole starter. If you don't want to add dry malt to your all
grain beer, you can put the starter in the refrigerator to settle
out suspended yeast, pour off the wort, swirl, and pitch the slurry.