Low alcohol brewing with aerobic 'fermentation'

[Agentgonzo]

Anaerobic fermentation converts sugars into alcohol and carbon dioxide. But aerobic respiration of yeast converts the same sugars into water and carbon dioxide.

Has anyone experimented or tried 'fermenting' a beer aerobically for the vast majority of the fermentation (open vessel, constant agitation to prevent a CO2 blanket forming and to aid in redissolving O2 - something like a giant starter/stir plate), then finishing off the last few SG points normally to remove dissolved oxygen? _in theory_ this would produce water rather than oxygen and lead to a low ABV beer with the same malt profile.

But I know that fermentation isn't that simple conversion and a lot of other things happen to give you the flavours from the fermentation.

There is also the oxidisation you'd need to think about... But AFAIK, most of the oxidation issues are caused by the hop compounds oxidising... So you may be able to get around this by brewing your wort without hops and then with a large dry hop charge once you move to the anaerobic step, or even brewing up a super hoppy concentrated wort and blending that with the aerobically fermented batch.

I'm tempted to give it a try on a small 1 gallon batch just to see what happens, but I'm wondering whether anyone has thought about or tried it before?

 

[Bernie]

Anaerobic fermentation converts sugars into alcohol and carbon dioxide. But aerobic respiration of yeast converts the same sugars into water and carbon dioxide.

Has anyone experimented or tried 'fermenting' a beer aerobically for the vast majority of the fermentation (open vessel, constant agitation to prevent a CO2 blanket forming and to aid in redissolving O2 - something like a giant starter/stir plate), then finishing off the last few SG points normally to remove dissolved oxygen? _in theory_ this would produce water rather than oxygen and lead to a low ABV beer with the same malt profile.

But I know that fermentation isn't that simple conversion and a lot of other things happen to give you the flavours from the fermentation.

There is also the oxidisation you'd need to think about... But AFAIK, most of the oxidation issues are caused by the hop compounds oxidising... So you may be able to get around this by brewing your wort without hops and then with a large dry hop charge once you move to the anaerobic step, or even brewing up a super hoppy concentrated wort and blending that with the aerobically fermented batch.

I'm tempted to give it a try on a small 1 gallon batch just to see what happens, but I'm wondering whether anyone has thought about or tried it before?

Or start with less grain and use crystal malt.

 

[peebee]

Sorry, it doesn't (apparently). If there is plenty of food (like beer wort) the yeast saves the effort and ferments the sugar anaerobically. It even has a name: "Crabtree Effect". If it is left starving but plenty of oxygen yeast has the ability to feed on its own excrement; it'll convert the alcohol to vinegar for energy.