10 Nov 2010 @ 1:17 AM 
 

Siebel Concise Course: Day 7 – Fermentation

 

We continued with our cold-side education today, finishing up yesterday’s yeast discussions and talking about fermentation control, good fermentation practices, cask conditioning, and control of fermentation flavors.

Today was also the last day that we received instruction from Kirk Annand who, I must say, has been fantastic. His are probably my overall favorite sections, thus far. His teaching style is very forthright, he has a clear grasp on a vast array of topics and apparently enjoys imparting that knowledge. I sincerely hope that I cross paths with Kirk again in my career in the brewing industry – and I hope I can get up to Nova Scotia sometime to sample some of his beer.

The information today was a clearinghouse of information about yeast and fermentation management, primarily focused around flavor control. It was part, “Don’t do X, Y, and Z so you avoid off-flavors.” and part, “If you happen to have off-flavors, you can control them by doing A, B, and C.” This is everything from yeast pitching rates to fermentation temperatures to proper yeast management, how esters are formed in your beer, when the most effective time to do a diacetyl rest is, how to measure glycogen levels and easy tips on how to measure the (rough) viability of your yeast without using a microscope.

The cask conditioning section was a treat, showing various different implements used in cask-conditioning beer which turns out isn’t any more complicated than:

a) it looks
b) it does when I did it a few weeks ago

If anything, I learned that I may have aged my beer too long and that most cask conditioned ales will condition in just a few days which, from a homebrew perspective, I just wouldn’t have assumed.

By 4:00, when we started our tasting, my brain felt full.

Tasting today was a damn sight better than off-flavor tasting yesterday. We did German and Belgian styles today and went through the following examples:

Bitburger Pils (German-style Pilsener)
Flensburger Dunkel (European-Style Dark)
Paulaner Hefe Weissbier (South German-Style Hefeweizen)
Franziskaner Hefe Weissbier Dunkel (German-Style Dark Wheat Ale)
Uerige Alt (Dusseldorf-Style Altbier)
Wittekerke Wit Bier (Belgian-Style White Ale)
Duvel (Belgian-Style Pale Strong Ale)
Bourgogne Des Flanders (Belgian-Style Flanders/Oud Bruin)
Chimay Cinq Cents (Belgian-Style Tripel)

Aside from the Uerige which was amazingly off, this was a really fantastic way to end the day. My only complaint (complaint? really?) is that I got a little tipsy while tasting them.

I know. It’s a hardship.

Tomorrow we start in post-fermentation: Filtration, QC, and Carbonation. We also get our last sensory panel in which I imagine we’ll get fantastic things like that wonderful aroma when you have chlorine somewhere in your beer: band-aids. Yum.

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Categories: industry
Posted By: erik
Last Edit: 10 Nov 2010 @ 01 17 AM

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Responses to this post » (10 Total)

 
  1. Matt says:

    Thanks for all the wrap ups!

    So according to the class, when is the best time to do a diacytl rest? Very curious.

  2. erik says:

    Start your diacetyl rest when your fermentation gets down to half your original Plato (or a little lower).

    What you’re shooting for is to start your rest when yeast has finished log phase (growth and reproduction), since that’s when it’s creating most of its flavor compounds and alcohol (and letting temperature rise for a diacetyl rest could effect how those are created and how much there are if the yeast were still growing).

  3. Matt says:

    Cool, thanks! Any talk about the pitching cold/no rest method? Only tried it once, boy did I get butter.

  4. erik says:

    Well.. it’s really going to depend on what you’re making, but my guess is that, yes, that you wouldn’t have any way to actually get rid of as much diacetyl as you could in that case.

  5. Matt says:

    Oh yeah – was talking about lagers, and pitching cool and letting rise to fermentation temp, and holding it there. So, if you wanted to ferment at 50F, pitch at 45F.

  6. erik says:

    Okay – with lagers you need to do something to reduce diacetyl since you’re under pretty strict temperature control. The yeast naturally creates the pre-cursor to diacetyl as part of its energy production, and that pre-cursor will spontaneously change to diacetyl over time in your beer, especially at higher temperatures.

    If you don’t do a diacetyl rest in your lager, then you’re probably going to end up some SOME in there, even if you don’t taste it when you go into packaging it can form afterwards – especially if the temperature happens to rise AFTER packaging (say when if you’re bottle conditioning).

    On the other hand, there’s a number of other variables there. The universal answer for all things brewing (as they have taught us in this course) is, “it depends….”

    What is this cold pitch method supposed to accomplish?

  7. Matt says:

    Jamil is a big proponent of cold pitching lagers – saying that if you pitch enough yeast, you won’t need a d-rest as there will be minimal growth. The one time I tried it, well, let’s just say it was one of the few batches I’ve dumped. I’m in the “better safe than sorry” camp now, and just do the rest. Thanks again for the info!

  8. erik says:

    Oh, but he’s right! But you REALLY have to pitch enough yeast, and maybe even over pitch a little. That still isn’t going to get rid of acetolactate, though (which is the precursor to diacetyl). You might not need a warm diacetyl rest, but you should at least let the yeast hang around in the fermenter long enough for that diacetyl to be created and then be reduced by the yeast.

  9. Matt says:

    Ah – yep, it was one of my first lagers, so probably did underpitch. Lagers, especially light ones, are so tricky! And there’s so many different approaches. The last one I did was a dark lager, and I did the cold pitch and a d-rest, came out fine. Still settling/figuring out my lager process – cheers for the tips mate.

  10. Thomas says:

    Interesting points on the cask, I know Brad at Big Boss likes to prep a cask no less than three weeks out based on his training and experience. He doesn’t get the flavors out of it properly otherwise.

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