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Monday, December 17, 2012

Genentically-Modified Yeast is Reinheitsgebot-Compliant?

An unidentified emailer (hat tip: anon) sent a link to a story at Chemical and Engineering News:
You often see copies of Reinheitsgebot at breweries like this
one at Paulaner in Munich.
[At Weihenstephan], undergraduate student researchers have slipped biosynthetic genes for caffeine into beer-brewing yeast so that one day we may drink a pint of beer and defy sleep at the same time.  The team has also inserted into the yeast the genes required to make the citrus flavoring limonene. And they’ve tinkered with genes to make xanthohumol, an anticancer agent that additionally blocks hot flashes in menopausal women...

But the project is also radical because genetically engineered food is controversial in Germany. Curiously enough, though, the new genetically engineered yeast could provide a loophole for German brewers who might want to experiment with beer additives without disobeying the Reinheitsgebot...  [I]n principle, brewers of the future could slip all sorts of interesting flavors into beer through yeast. They’d still be able to add the Reinheitsgebot seal to their bottles because the flavors wouldn’t be inserted as additives.
Two things.   One, I think it actually would violate Reinheitsgebot, which has resisted all kinds of innovations and forced brewers to do cockamamie things to, for example, adjust the pH in their mashes.  (No adding lactic acid!--you gotta make it naturally.)  I'm not sure what loophole the chemists think there is (that yeast wasn't originally included as an ingredient, maybe?), but I don't see it passing muster.

Secondly, and more importantly, Reinheitsgebot is, in this European Unionized age, more an artifact of culture and a brewing mission statement than an actual law.  Brewers adhere to it far more because it puts them in a centuries-long tradition of German brewing and because German drinkers themselves put serious stock into the notion of "purity."  There's just no way GMO yeast passes the smell test for being Reinheitsgebot-compliant.   I don't think even think Americans would go for it, much less Germans.

But I'll throw it out there.  What do you think--designer yeasts that make your beer more citrusy, blocks hot flashes, and gives you a caffeine boost.  Kosher?  An offense against God?


  1. But if it is used by a brewer of under 6 million bbls of production and it is casked, it is both real and craft. Doesn't that mean anything to this conversations??!??!??!

  2. As a bioengineer turned brewer, it appeals to the geek in me. As with any additive or procedure change, it is the brewers responsibility to identify and control the byproducts of the fermentation process to ensure the safety of the finished product.

  3. "Secondly, and more importantly, Reinheitsgebot is, in this European Unionized age, more an artifact of culture and a brewing mission statement than an actual law."

    Sorry, but it is an actual law (in Germany). It only applies to beers brewed in Germany, but it was updated in 1993 as the Vorläufiges Biergesetz (das Gesetz means "the law").

    The Wikipedia is fairly accurate:

  4. Question: Do they use GM barley? And how about chemical pesticides, fertilizers, etc. that are for sure used in crops? How about the chemical modification of water?

  5. The "caffeine boost" part of this just sends us back down the Four Loko rabbit-hole of mixing stimulants and depressants. No thank you.

  6. So is the caffeine rabbit hole inapplicable to the countless number of coffee beers that are readily available?

  7. Yes. Coffee is used mainly for flavor in beer, not for its caffeine contribution, while caffeine doesn't provide much in the way of actual flavor or substance in beer. It functions mainly as a stimulant. Hence the Four Loko reference, which relies on caffeine but not coffee. I don't see the necessity of caffeine in beer by itself. Do you?

  8. *shrug* not really, but that wasn't my point. I'm well aware of why coffee is used in beer. But I'm assuming it still adds levels of caffeine to the finished product. If the levels added to a beer without coffee are comparable, I don't see what the fuss is about.

  9. My impression is that the amount of caffeine contributed by coffee in beer is much smaller than the amount of pure stimulant added to a can of Four Loko (reportedly 2-3 times the amount of caffeine in a cup of coffee).

    As for GMO yeast, I don't much care about the caffeine or anti-hotflash components, but hey, if they use can get some good flavor out of it (extra citrus, etc...), why not?