Harvesting Bottle Yeast
Beer
Date: Mon, 27 Jan 2003 12:12:07 -0500
From: "Steve Alexander"
Subject: re: Yeast Question/bottle culturing

Chuck D. asks about culturing yeast from a bottled beer.

>I am looking for some advice/help on culturing a
>starter from a bottle
>of Paulaner HefeWeisin (sp?). I fell in love with this
>beer recently

Unfortunately for the yeast scavengers, most hefe-weizens use a different
bottle conditioning yeast. I dont specifically know about Paulaner. As
far as how to culture from a bottle, Ive considerable expertise on that.

Live yeast cell concentrations in most bottled beers are low. If the beer
is filtered the reason is obvious. Even if there is considerable yeast
sediment, often shipping and storage have seriously reduced the number of
live cells. You cant always directly use beer to streak-out on a plate and
expect colony growth. The cell concentration is often too low.

My method is to remove about 85% of the beer - leaving any sediment intact.
then add about 40% of the bottle volume as fresh sterile wort. Aerate by
shaking & mixing with the headspace air and incubate in a warm area -
75F-80F.

Of course sanitation procedures must be comparable to those used to create
slants.
Sanitize the sealed bottle and all tools with a soak in iodophor soln.
The culture wort should be recently boiled or pressure cooked and then
cooled in sanitary conditions. Id strongly recommend you use gloves -
latex disposables are nice, but dishwashing rubber gloves work too. Its
much easier to sanitize the glove surface than your skin surface. A face
mask is a good idea. Wipe down the work area w/ sanitizer. HEPA filtered
air if you have one. You have to think too - its very easy to unwittingly
touch a faucet or a drawer handle and contaminate the work.

You pop the cap w/ sanitized opener, flame the bottle lip and pour out 80%
of the contents gently. Flame the lip again, then add culture wort to the
bottle. Seal and shake vigorously. You could add a fermentation lock,
but the growth rate will be extremely slow and a saran & rubber band (both
sanitized) make a perfectly acceptable seal.

The bubbler or the saran should eventually show a little activity - but
*very* little. Under good circumstances youll see activity in 3-4 days.
For a well filtered beer like the Michelob it may take 2 or 3 weeks to see
the saran bulge !

Anyway after you see some activity you could streak-out the sample to create
a clean culture with good confidence youll see colonies. If the sample
smells clean and was active fairly quickly - its reasonably safe to step it
up through a few starter stages and then pitch it into a batch - assuming it
still smells and looks good..

For beginners you can culture from Sierra Nevada Pale Ale quite easily.
Many Belgian beers produce good working cultures readily, Chimay for
example, but its hit & miss. Ive had difficulty Unibroue - I suspect
their yeast autolyzes readily. For a challenge try a filtered beer. Ive
cultured very nice smelling (low infection level) ferments from Michelob on
two occasions. Despite what you read - even filtered beer contains viable
cells.

If you have the equipment and really good sanitary conditions its better to
place the sample+wort on a stir plate - sealed. You are doing more handling
this way and Id so dont try it unless your sanitation is impeccable.

-S

1/28/03
Harvesting Bottle Yeast