09 Nov 2010 @ 12:10 AM 

Siebel Concise Course: Day 6 – Yeast, Yeast and more Yeast


Let me introduce today by putting it like this:

Last week, I took about a page of notes, all told. Easily half of them were ideas or things to check out once I got back to North Carolina.

Today, I took 3 pages of notes.

I’m not even sure where to begin with the wealth of information today. What our schedule says we were going to cover was:

The Nature of Yeast (this is essentially an introduction to cell biology)
Yeast Growth and Fermentation
Biological Control (not yeast, but close)
Brewery Effluent (so that Lyn could get a break, I think)
Yeast Maintenance and Propogation
Yeast Management

and that was all before we got to our sensory panel for the day. We almost made it through the entire schedule. We probably have about a half a “lesson” left. With the number of amazing tangents that Lyn went on today, that’s probably looking like at least an hour maybe more.

So why all the notes? Because there was so much supplementary material that wasn’t presented in the slides – good, useful, practical, supplementary material. Things like types of media used to grow lactic bacterial cultures in (to check to see if they’re in your beer, you see), what they’re called and their different levels of usefulness. Or the best method for pulling yeast for pitching out of a conical fermenter (and why to do it that way). Or how to get a single colony off of a streak plate. Or the easy way to do a Catalase test. Or how many bacterial colonies per mL of wort you need in order to actually have flavor change, and how many times you can expect a bacterial colony to multiply in an average wort (thereby giving you the lower limit at which you can allow bacteria in your beer … which should be zero unless you put it there on purpose). Just tons of good, practical information.

Same goes for brewery effluence, too, actually. Herein lay a bunch of actual practical, “This is the kind of thing that people who run sewage treatment plants don’t like…” kind of information. Just awesome.

This afternoon we had another sensory panel – technically off-flavors, though “flavors” is probably most accurate. In a Budweiser control we had:

Alcohol (+5% alcohol, thereby creating 10% alcohol Bud)
Acetaldehyde (tastes like green apple, unripened banana, mown grass)
Diacetyl (the thing I am probably most sensitive to, tastes like butterscotch)
Isoamyl acetate (a common ester, especially in hefeweizen, tastes like banana)
Ethyl acetate (a common ester, normally below flavor threshhold in beer, tastes like fingernail polish remover, airplane glue)
Ethyl hexanoate (a common ester, tastes like anise)
Eugenol (and stand-in for 4-ethyl guaiacol, ie – clove flavor)
And a mixture of isoamyl acetate and eugenol to create a “hefeweizen” flavored Bud.

All in all not a terrible tasting, but I am so sensitive to diacetyl that it actually stayed with me for the entire walk back after I tried all of those other flavors and everything. Yick.

Tomorrow, we get another fun-filled day with Cleaning and Sanitizing, Fermentation Practices (woo!), Cask Conditioning (double woo!), Control of Fermentation Flavors, and our other “Styles” tasting.

Cold side is a lot more fun than hot side.

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Categories: industry
Posted By: erik
Last Edit: 09 Nov 2010 @ 07 53 AM


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