From the HBD Archive
From: STROUD <STROUD%GAIA@leia.polaroid.com>
Subject: dry vs liquid yeast; debunking the RS Ale Momily
Date: 1992-03-09 19:54:00 GMT

I know where I stand on the issue of dry vs liquid yeasts: I changed to single
cell cultures a long time ago and haven't looked back. Today, I would rather
not brew then throw a pack of dry yeast into my wort. I feel that strongly
about it. It's not that good beer can't be made with dry yeast, it's just that
it's a roll of the dice when you use it, and I'd rather not gamble with hours of
my work.

On the other hand, it's a free country and I figure that everyone can use
whatever makes them happy. Dry yeast is cheap and easy to use, just like corn
sugar. You can make beer with both and learn to like it. Just don't expect
everyone else to.

But on to the main reason for this post:

Hidden in the midst of the on-going dry vs liquid (single cell culture) yeast
debate is what appears to be a universal condemnation of Red Star Ale yeast.
Well, I'm here to come to the defense of Red Star Ale yeast and to break a
momily:

Red Star ale is actually a nice, clean somewhat unattenuative yeast. It's the
other crap inside the yeast packet that causes all of the problems.

I base this statement on an experiment that I performed for my homebrew club,
the Boston Wort Processors, about two years ago. The following excerpt is from
Vol. III, # 5 of our newsletter:

To quote:

**************
"Red Star Ale yeast has a very bad reputation among homebrewers. It usually
produces a unique banana-y phenolic-clove taste in any beer made with it. This
may be desirable in certain wheat and Belgian brews, but is not generally
regarded as a positive element in most beers.

Are these characteristics due to the particular yeast strain in Red Star yeast,
or are they due to some bacterial or wild yeast contaminant?

THE EXPERIMENT
To answer this question, Sheri Almeda cultured Red Star Ale yeast on agar plates
and isolated four single cell yeast cultures. I brewed a batch of beer and
split it into 5 one-gallon jugs. The 5 jugs were fermented with the four yeast
cultures and dry Red Star Ale yeast.

THE RECIPE
1 can (3.3 lb) M&F Lager kit (contains 7.5 AAU's)
1.5 lb M&F hopped dry malt (3.8 AAU's)
1 cup firmly packed brown sugar
1 tsp gypsum

The above ingredients were boiled in 3.5 gallon water for 30 minutes, then 0.5
oz of Fuggles leaf hops were added, the wort was removed from the heat, and
quickly force cooled.

The hops were strained off and enough boiled/cooled water was added to yield
~4.5 gallons final volume. The bitter wort was racked into 5 one-gallon
sanitized jugs, filling each ~3/4 full. The yeasts were pitched (the cultured
yeasts had previously been started to give 125 ml of actively fermenting starter
and the dry yeast was rehydrated and active) and the airlocks were attached.

S.G. 1.042

The fermentations were single stage for 2 weeks at room temperature.

THE RESULTS
The dry yeast showed signs of fermentation within 3 hours. All of the cultured
yeasts showed signs of fermentation within 6 hours.

The dry yeast finished fermentation in ~4 days, the cultured yeasts finished in
~6 days. The dry yeast's ferment looked very opaque, while the cultured
yeasts' ferments were very clear with suspended particles.

Approximate final gravities at bottling:
Red Star Dry: 1.008
Culture #1: 1.017
Culture #2: 1.017
Culture #3: 1.020
Culture #4: 1.022

THE TASTING:
The five beers were served blind in random order. Everyone picked out the Red
Star dry yeast fermented beer with no problem, calling it smelly, cidery, thin,
and phenolic. The other brews were mostly indistinguishable, but were described
as clean, sweet, tea-like, full bodied, and 'it doesn't taste like Red Star.'

THE CONCLUSION
I concluded that there is a contaminant of some kind in dry Red Star Ale yeast
that is responsible for its aroma/taste reputation. The cultured yeasts'
ferments were very clean, and showed none of the phenolic tendencies of the dry
yeast. The final gravities of the cultured yeasts were uniformly high, and it
leads one to wonder if this is a very unattenuative yeast.

This experiment also points out the problem with using dry yeast. You just
never know what's going to come out of that little packet. Even though the
dried yeast was very viable and got off to a fast start, the final product had
a contamination problem."

Addendum: It was suggested that a newly cultured yeast is not as active as one
that has already been through several fermentation cycles. To test this, I took
the slurry from the beer brewed with yeast culture #4 and brewed the same recipe
again. This beer fermented from 1.042 down to ~ 1.015, an improvement, but
still fairly unattenuative.

**********************

So there you have it. The problem isn't RS ale yeast, it's the _purity_ of the
yeast. In my opinion, that's also the problem with most dry yeasts. In and of
themselves they are good beer yeasts, but they are produced in such a manner
that their purity is compr _may_ (aThis may (and often does) cause defects to
arise in the final product.

Any comments???

Steve Stroud


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