FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
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Contents:
FlavorActiV vs. Siebel sensory kits ("Stephen Johnson")
RE: Siebel Sensory Training Kit vs. the FlavorActiv Enthusiast Kit ("David Houseman")
Re: stir plate oxygen limit (Fred L Johnson)
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Date: Fri, 20 Mar 2009 01:10:12 -0500
From: "Stephen Johnson" <sjohnson3 at comcast.net>
Subject: FlavorActiV vs. Siebel sensory kits
Brian questions the price/value of the Siebel kit described by Keith Lemcke
in HBD #5525 and Doug wonders if anyone has compared that kit with the ones
that the AHA has been providing homebrew clubs through the FlavorActiV
company.
Over the years that the Music City Brewers have been in existence (since
1996), some of us in our club have been able to have some experiences with
both kits, or at least some one or more versions of them. Early on, one of
our local brewing community members had gone through the pro brewers
training short course at Siebel and brought back the partially depleted
sensory evaluation kit that was part of the course at the time. He felt that
we might benefit from conducting some of our own training, since several of
us were preparing for the BJCP exam at the time. One of our members was
doing post doctoral medical research at Vanderbilt, and had access to some
very finely calibrated titration pipettes and borrowed them for our own beer
evaluation research. We were able to spike several cases of beer with some
of these sensory evaluation compounds, and did them in a way that we were
able to use each compound at different levels in 3 beers, so that one beer
was at the low threshold level, one at a medium level, and a third beer at a
high level. We were able to do this with about 12 different compounds, if I
recall, and we learned quite a bit about our own unique sensitivities to
various off-flavors commonly found in beers. I learned about my own overly
sensitive awareness to DMS, and could detect it at the very lowest levels,
whereas my friends could not pick it up at all at that same level. At the
same time, I also discovered that it is hard for me to detect the aroma of
diacetyl, even at the highest of levels, but that I can detect it more from
the mouthfeel (slickness). Both of these facts helped me to be a better
judge in terms of knowing my own sensitivities and/or limitations. I also
learned that I hope I never have to judge a beer that has high levels of
isovaleric acid in it. That one just about made me throw up on the spot.
It sounds like the current kit available from the Siebel training has 24
different compounds which run the gamut in terms of flavors found in typical
beers as well as problematic off-flavors that are not very desirable,
especially at higher levels. I think there are some definite benefits to
these compounds being in liquid form in how easily they can be stirred into
a sample of beer and at different levels, which was how we used them back in
the late 90's.
More recently, our club has purchased the FlavorActiV kit through the AHA,
and while helpful, we found the kits to be somewhat limited in the scope of
the flavor compounds being sampled and the amounts of each, which limited
the number of participants we could include in our tasting session to about
12 individuals, because we opted to use them in a two-fold training process
where each sample was used during an education and orientation phase, and
then a second round was done "blind" at a lower threshold level to see how
well individuals could evaluate each of the compounds in a random order. The
kits themselves were put together well, but were limited in that only 8
flavor profiles were provided, and they apparently have been chosen as
representative if typical problem conditions in beer production (metallic,
acetic acid, bacterial growth in the mash, spoilage by wild yeasts,
bacterial growth in the fermentation, insufficient boiling of wort, poor
yeast health, and use of old or degraded hops). They are also hard to use in
that the compounds are powdered, and are "loaded" in pre-filled capsules
that basically have to be discharged into a beer pitcher and then beer
poured over the powder, and then stirred for some time to thoroughly
dissolve the granules. Thorough rinsing of equipment is required in between
each sample to prevent cross-contamination. Extra costs to these sessions
involves large quantities of sampling cups, several cases of "light"
commercial beers, and enough pitchers to be able to handle the various
samples. We also printed up color copies of handouts and other documentation
that came with the kit so that every participant came away with very helpful
information about the process and a place to write notes to refer back to in
the future. We did this as part of our club's ongoing judge training in our
efforts to provide our region with more viable and well-trained BJCP judges.
Now, as for debating the costs, I suspect there are some highly trained
chemists out there in beer digest cyberspace who can probably provide a more
informed response for Brian, but my understanding of the whole process of
isolating these chemical compounds is that it is a very complicated and
exacting process that is well beyond the means of the ordinary homebrewer. I
recall looking through some of the information from the FlavorActiV site,
and was amazed at the complexity and detail that they were involved in. Not
just beer, but all levels of food service and beverage industry evaluation
and training worldwide. These compounds are isolated and processed and
packaged in levels of purity that I suspect are similar to the precision
that is provided by the pharmaceutical industry.
Granted, it is a high price to pay, and there are certainly other ways to do
sensory evaluation training that are a lot less expensive, and some of them
have been documented by various individuals involved in the BJCP and I
believe are posted on their website. I haven't tried them myself, but I
think some in our club have done a few of those over the years.
But, like a lot of things in life, each to his own. Some may want to drive
to work in the latest model BMW sedan, while another may feel completely
satisfied getting to work reliably in a Toyota Yaris.
I think the acronym is "YMMV".
Steve Johnson
Music City Brewers
Nashville, TN
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Date: Fri, 20 Mar 2009 07:39:01 -0400
From: "David Houseman" <david.houseman at verizon.net>
Subject: RE: Siebel Sensory Training Kit vs. the FlavorActiv Enthusiast Kit
Doug,
I've used both kits. They were very similar. Both easy to use. Most
recently we used the kit provided by the BJCP (this is free to those giving
the BJCP exam and conducting a training class). This kit had 10 different
flavor/aroma capsules. This was well received by those taking the class.
Of course some characteristics were easier to pick out than others for some
people. The BJCP will be making an announcement about its program shortly.
My recommendation would be to wait and see if you want to participate in
that. Otherwise the new Siebel kit with 24 different samples is the most
extensive sensory evaluation kit and it would be my choice were I to pay for
one. However with 24 samples you'd probably want to use these in more than
one sitting.
David Houseman
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Date: Fri, 20 Mar 2009 07:40:37 -0400
From: Fred L Johnson <FLJohnson52 at nc.rr.com>
Subject: Re: stir plate oxygen limit
Matt wants to increase the concentration of cells in his starters and
the total number of cells in the product. He is using a stir plate
and loose foil over the top of the culture vessel. Matt is comparing
his starters to others who report getting about twice the
concentration of cells in their starters.
In the system Matt is using, the concentration of cells will heavily
depend on the concentration of the nutrients in the wort used in the
starter (sugar, etc.). The total number of cells he gets will depend
on the concentration of the nutrients and the volume of the starter.
The cells simply stop growing when they run out of nutrients. If you
want to increase the concentration of cells in your starter, increase
the nutrient supply. If you want to increase the total number of
cells, increase the total amount of nutrient you provide the cells. I
really think it is that simple.
I typically use wort from a previous batch as the medium to which I
add Fermax at about 2 g/L. (If I brew a very large beer, I'll dilute
the wort down to a specific gravity of about 1.05 for use as a
starter.) I start from a slant and get the yeast going in about 50 mL
of dilute wort (S.G. about 1.02). As soon as I see good activity, I
transfer this to a spinner flask an add about 300 mL of wort and step
up from there twice for a 2 L starter. I pump filtered air into the
head space, so I probably do get more air into the wort than one
would get by convection in a loosly covered Erlenmeyer flask, but I
don't expect there to be a lot of difference.
For the last seven starters the gravity of my worts ranged from
1.04-1.06 and they produced 153-347 million cell per mL. The volumes
of the starters ranged from 500 mL to 1900 mL, and the total number
of cells produced was 124-470 billion cells. Of course the 500 mL
starter produced fewer total cells than did the 1900 mL starter.
There is a rough relationship between the gravity of the starter and
the concentration of cells when finished. I expect that relationship
will tighten up as I get more data points.
Please don't get me started again on the olive oil myth. If you are
willing to experiment by adding a small amount of soap (or
nonesterified fatty acids), then let's talk.
Fred L Johnson
Apex, North Carolina, USA
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End of HOMEBREW Digest #5527, 03/20/09
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