From the HBD Archive
From: dsbaer@EBay.Sun.COM (David Baer)
Subject: Liquid yeast
Date: 1989-03-27 17:33:43 GMT

There are two basic types of liquid yeast products.
One comes in little vials and requires the use of
a starter (it cannot be added directly to the beer
you intend on fermenting). It must be added to a
small quantity of wort first to reactivate the
yeast and then this is added to your beer. A major
supplier of this is MeV out of Canada (Toronto, I
think). I have never used this product so I have
no comment.

The other type of liquid yeast is found in foil pouches.
Inside the pouch is a pocket of yeast surrounded by
liquid nutrient. The pocket of yeast needs to be broken
in order to mix with the nutrient and reactivate the
culture. It usually takes 1 to 5 days for the culture
to reactivate and then you only have about 2 oz of liquid
to add to the wort. This product is made by Wyeast and
is called Brewer's Choice. I have seen Wyeast products
through many different mail order catalogs and it seems
to be the most widely available.

I have found that the Wyeast products have been
very good. I used their German Lager Yeast (#308)and
got a thorough attentuation and sparkling clear
beer. The yeast seems to produce a noticeable
scent but it is by no means unpleasant.

I have also used Williams Brewing Co. American Lager three
times and had very nice results. This yeast is made by Wyeast
and I suspect is identical to the Wyeast St. Louis
Lager. The American Lager ferments very clean with
almost no discernable flavor or odor. The main difference
is the American Lager does not seem to ferment the
brew as completely as the German Lager and a residual
sweetness is left behind.

The bigest issue with the Wyeast product is whether to
add the yeast directly from the package to the wort or
to use a starter. I have tried both and have had equal
success. The readers of this digest seem to favor using
a starter.

I have not used the Wyeast Ale cultures. Instead I culture
the yeast from the dregs of either Sierra Nevada or
Cooper's Real Ale. My local supply shop sells agar slants
and complete instructions. It is very simple, just pick up
a drop from the bottom of a bottle, and scrape it across
the agar. Within a week the yeast will start to grow. Once
you have a culture take 1 oz of sterile wort and put it in
the slant and gently shake. Let it sit a couple of hours and
then add it to a quart of the same sterile wort.
Within a few days it should start to show noticable
signs of fermentation. The quality of the yeast is unquestioned,
but you need to be very careful about sanitation in order
to produce a clean specimen. If there is some contamination
you can tell from the culture in the agar. Yeast is creamy
colored, either white or light beige. If there is yellow
or green growth in the agar, toss it out and try again.
Another area that can mess up is the starter. If the starter
has a difficult time getting going (more than a week),
then chances are there is something nasty inhibiting the
yeast. If you are on a tight schedule always have a
packet of dry yeast around just in case. I have cultured
yeast for a year and gone through the process 5 times, and
have not had a problem yet. I am by no means a super careful
brewer so if I can do it, anybody can do it.

I recommend reading "Yeast Culturing for Homebrewers" by Leistad.
He gives very thorough instructions almost to the point of
overkill, but it is better to know more than less.

The move to liquid yeasts has had a major impact on the quality of
the beer I brew. I highly recommend their use and, even though
they are more expensive, you can culture them and stretch
one package to make 5 or more batches which brings the
price down to the same level as dry yeasts.

Dave Baer
Beer Enthusiast,
Sun Microsystems, Inc.

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