Completely Aerobic Fermentation?

[rasherb]

I think this is a question for the science thread.

Is it possible for yeast to consume all the sugars in a wort without going anaerobic? What would the resulting beer be like?

 

[cshamilton]

I don't know about flavor, but they don't produce much alcohol unless they go through anerobic metabolism.

 

[Wakadaka]

Interesting question. I wonder if it would still be recognizable as beer, or actually fall under the category of beer. If I remember correctly from my bio class, the two processes are drastically different, so I imagine the results would be incredibly different.

 

[giligson]

Yeast actually prefer anaerobic metabolism in a sugar rich enviroment. Even if you bubble in air, if the glucose concentration is above about 1% (sorry I can't recall the exact figure) they will preferentially take it anaerobically. Its only when they get down to the last little bit of carbon source that they will switch over to aerobic metabolism. The truth is actually more complicated - its called the Crabtree effect, and it entails shunting the glucose through a strange pathway to ethanol. Its not just simple catabolite repression.

 

[wesleyjo]

Are beers that are fermented in open containers any different vs. beers that are fermented in tanks because of this effect?

 

[scotched]

Are beers that are fermented in open containers any different vs. beers that are fermented in tanks because of this effect?

They are different, but not because of that effect.

The idea is that open fermentation allows excess carbon dioxide to escape, rather than being forced back into the solution (if bottle-necked) and putting a strain on the hardworking yeast. It has little to do with letting o2/air in the vessel.

edit: This is only conjecture^