HOMEBREW Digest #5527 Fri 20 March 2009

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  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 Return to table of contents
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 Return to table of contents
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 Return to table of contents
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