Servomyces experiment results (long)
By Mark Tumarkin

<editor's note>
An interesting report (from the HBD, where else?), on a new product designed to 
make yeast happy. You do want your yeast to be happy, don't you??
</editor's note>

Date: Tue, 26 Feb 2002 09:24:12 -0800
From: "Kraus,Drew" 
Subject: Servomyces experiment results (long)

Well, it's about time I got back to the collective regarding the results of
my little Servomyces experiment.  As a reminder, I'd read some glowing
reviews regarding Servomyces (a yeast nutrient currently being marketed only
to commercial brewers by White Labs - NAYYY - check out
http://www.yeastbank.com/features/servo.htm), and after managing to get my
mitts on some, I wanted to see just what effect it has on the fermentation
process and final product.  First of all, I'd like to thank those who
responded to my question regarding how to control for yeast-pitching
differences (controlling for variation between yeast batches and size of
pitch).  Opinions varied, and in the end I followed the advice of a number
of you, including Dr. Chris White at White Labs, and used separate pitchable
vials of the same strain (California Ale - WLP001) bearing the same batch
number.

Beyond that, my plan was to mash-up a 10-gallon batch of IPA (may have been
better choices for the 'spurriment, but I wanted an IPA on tap, soooo...)
then split it in half; boiling, hopping, cooling and pitching each sub-batch
consistently, with the only planned variation being the addition of a dose
of Servomyces added to the last 10 minutes of the boil of the second batch.
Now, I should note that the 10-gram packet of Servomyces that I was using is
enough to supply a 10-barrel batch of beer.  As I figure it, I should be
able to do about 30 10-gallon batches with that.  Herein lies the first
variable.  Not knowing anyone who would have a scale accurate enough to
measure out one-third of a gram (if you know what I mean... and I think you
do), I followed the advice of Bob Sheck and eye-balled it, following his
description of "no more than can be gathered on the blade of a jeweler's
screwdriver."  The good news is that White Labs hopes to have a homebrewer's
version of Servomyces on the market soon.

I brewed, cooled and pitched both batches.  As I'm still getting used to my
new brewing system, I ended up with closer to 8 gallons of 1.062 wort,
rather than the 10 gallons I'd been shooting for.  Oh well.  I chose not to
aerate, as I felt that it would be difficult to be consistent between
batches.  Among the things that I noticed with fermentation (in glass
carboys) were:
1) the Servomyces batch began showing signs of fermentation in about 8
hours, whereas the "control" batch took about 20 hours.
b) the krausen on the Servomyces batch was consistently about twice as high
as on the control (if there was half an inch on the Servo batch, there was a
quarter-inch on the control... at high krausen, there was about 3 inches
atop the Servo batch and (you guessed it) about 1.5 inches on the control)
iii) just watching the activity in the wort, the Servo batch seemed to have
a more active "churn" going, but I have no idea how to measure or even
describe the difference... perhaps there's a standard "snow globe"
measurement out there someone can point me to

 ... here's where thing got a little, umm, "interesting" with the process.
See, I hadn't counted on San Jose's cold snap happening right around then.
Cheap such-and-such that I am, even in the name of brewing pseudo-science
I'm not going to heat my apartment at night or while I'm away at work or out
of town.  That meant that the room temps in the ol' fermentation closet
would drop to around 55 degrees F for much of the day.  Hearty as WLP001 can
be, this was a bit much to ask.  The Servo batch slowed to a crawl (although
still able to lift the cap on the airlock) at a gravity reading of 1.018.
The control batch pooped-out all together (no airlock liftage) at a reading
of 1.024.  Tried rousting them, no luck.  Set up the old "desk lamp
incubator" in the fermentation closet... still no luck.  Finally, I gave in,
and still trying to keep things as consistent-ish, I split one more vial of
WLP001 (screw it, I eyeballed it this time!) between the two.  Turns out the
weather started warming a little in San Jose around that time too, and with
the desk lamp incubator doing its finest, the brew closet temps were closer
to 62 degrees F.  Fermentation activity perked up... and there was much
rejoicing.

I gave them another 2 weeks to finish off, and both did so.  The Servo batch
finished at 1.010.  The control batch finished at 1.013.  I kegged both
batches, carbonated at 12 PSI for a few days and started serving (at long
last!).  I imagine that the differences in the end product are directly
attributable to the FG difference. As an apprentice judge some observations
worthy of note were:
A) both batches settled well, although I wouldn't give either the "clean &
bright" visual description I've judged on some beers
**) there was a more pronounced hop aroma to the Servo batch, both
highlighted the caramel malt sweetness present in the recipe
III) the Servo batch had more pronounced hop bitterness and flavor, while
the control batch had a more "rounded" and smoother balance
iv) there was a bigger, softer mouthfeel to the control batch
5) "January 32nd - The Servomyces batch announced its presence with
authority.  The caramel sweetness set out in a frenzied dance across the
palate, chased feverently by a never-tiring and ultimately triumphant hops
bitterness spurred on by a well-carbonated, but not "fizzy" mouthfeel.  The
flavor of the Cascade hops didn't bother to wait for even the first sip to
commence, choosing instead to march right in with the aroma and set up shop
in the imbiber's quaffing experience, eventually sharing, though never
conceding territory to the malt sweetness at mid-glass, whilst a mild
alcohol charge kept the pot ever-stirring.  

Jan 33rd - The Control batch matched the aggressive hops "yin" with a warm,
friendly malt "yang".  Rivulets of hops flavor "cascaded" across the tongue,
playfully teasing the caramel malt undertones at mid-sip.  By sip's end,
said malt undertones had had just about enough of that and filed a complaint
with the IOC alleging tainted scoring by the west coast judge.  The IOC,
being in Utah, washed it's hands of the controversy stating that it had no
authority to mediate given that the contentious liquid's alcohol levels
exceeded local statutes anyhoo.  By mid-pint, however, the alcohol undertow
began to exude it's cheerful warmth, and working hand-in-hand with a sturdy
mouthfeel, peace and harmony reigned throughout the palate." (Please note
that the above judge failed to sign his score sheet, scrawling only the
initials "BK")

For what it's worth, those were my observations.  Feel free to ask questions
either directly to me or on the open forum.


Brew on!

Drew Kraus
San Jose, CA (Rennerian-challenged)

Back to March 2002 front page