[jimrod]

I've tried to have serious conversations on defferent forums about beer gas but everyone jokes and no one has answers. My beers have been giving everyone who drinks them bad beer farts. I don't know if it is something I'm doing wrong or do I need to modify my recipes. 
 
I did make 10 gals of Vienna  2 months ago, we are drinking it now and it's gassy. On Saturday I made the same recipe and cut the crystal from 4lbs to 2lbs to try to get the dextrin down. I even lowered my mash temp to 150 from 158 to get more fermentable sugars. All of these beers are kegged.
 
Should I be waiting longer? Some of this gassy beer is 10 weeks from grain, that should be long enough.
Should I try filtering?  Should I try pasteurization? Freezing? Microwave?
Could this be a procedure problem? Am I stressing the yeast some way to cause this condition.
 
It seems to happen with all yeasts. I use WLP001-2-5-7 and US04-5
My recipes are pretty standard.
 
No joke, this is a real problem.

[tschmidlin]

Post some recipes, stats (OG, FG, etc), and sample procedures for us to take a look at.  Are there any homebrewers in your area with similar problems?

As a side note, 2 lbs of crystal per 5 gallons of Vienna is a lot?  Even 1 lb is too much for the style I think.

[dbeechum]

In all honesty, the primary culprit is going to be the yeasts. Not anything special that they're producing, just their sheer presence. If you filtered your beer, I'd bet the problem would reduce.

[oscarvan]

In all honesty, the primary culprit is going to be the yeasts. Not anything special that they're producing, just their sheer presence. If you filtered your beer, I'd bet the problem would reduce.

No, not joking here.

Would the gas produced then not be mostly CO2 and not Methane? IOW all noise no bouquet? This is, in fact the way I am experiencing it when I tap a green beer, and frankly, I don't see the problem.....

[tschmidlin]

It could also be that the beer has more soluble fiber than they are used to.

[bluesman]

This is mostly because beer contains alot of complex sugars, and when consumed in a large amount, it will pass into the large intestine without being absorbed by the stomach. The bacteria in the large intestine digests it, producing the gases CO2 and methane which then...well you know what.

So to help mitigate this...make lighter beers with less complex sugars. Mash low.

[gordonstrong]

I'm with Drew.  Look at the yeast first.  Try fining or filtering the kegs.

Those other tips can be checked out once you rule out the most likely problem.

Drink dregs of lambic sometime if you want to test this hypothesis.  I recommend you buy some digestive probiotic dietary supplements in advance, so you can help reset the good bacteria.

[jimrod]

Yes this is methane straight from the intestine, not hot air. The interesting thing is that everyone is effected and I don't want to offer beeno to everyone who tries my beer. Does anyone else have this problem?

Weather the beers are light or dark doesn't matter. The recipes are pretty generic with OG in the 1.050-1.065 range. FG in the 1.080-1.011 range. I've tried filtering with a 2 stage sediment filter (5 micron and then 1 micron) and this does seem to help. No one else is complaining about this problem out loud. I'm think I might be doing something wrong.

Is there a way to kill the yeast before serving?

[denny]

Is there a way to kill the yeast before serving?

This raises an interesting question....is gas caused merely by the presence of yeast cells, or does the yeast have to be live and functioning in order to cause it?  I guess I've always assumed it was just the presence of cells, live or dead.  But I know so little about physiology that it's just a WAG.

[Hokerer]

Yes this is methane straight from the intestine, not hot air. The interesting thing is that everyone is effected and I don't want to offer beeno to everyone who tries my beer. Does anyone else have this problem?

I only had the problem when I first started drinking homebrew - and even then only when drinking a fair amount.  I'd always heard that the gas was due to the presence of yeast in homebrew that's not there in most filtered commercial brews.  The gas seems to go away, though, once you've been drinking it for a while.  I guess your system just gets used to it.  That would also explain why the folks you're offering it to would be affected as their systems probably aren't acclimated to yeasty brew either.

[Hokerer]

Is there a way to kill the yeast before serving?

This raises an interesting question....is gas caused merely by the presence of yeast cells, or does the yeast have to be live and functioning in order to cause it?  I guess I've always assumed it was just the presence of cells, live or dead.  But I know so little about physiology that it's just a WAG.

Wouldn't you think that no yeast cells would be able to survive your stomach acids?  Since the gas is created further along in the "system" than the stomach, I wouldn't think any of them would still be alive at that point.

[denny]

Good point.

[euge]

Is there a way to kill the yeast before serving?

This raises an interesting question....is gas caused merely by the presence of yeast cells, or does the yeast have to be live and functioning in order to cause it?  I guess I've always assumed it was just the presence of cells, live or dead.  But I know so little about physiology that it's just a WAG.

Wouldn't you think that no yeast cells would be able to survive your stomach acids?  Since the gas is created further along in the "system" than the stomach, I wouldn't think any of them would still be alive at that point.

Organisms can pass through the stomach and survive. Whether they can survive the duodenum, jejunum or ilium is another matter. I attribute "gas" to the fermentation of complex carbohydrates that pass into the colon where the native flora attempt to digest the sugars. Yeast has more of a laxative effect IME.

[denny]

Organisms can pass through the stomach and survive. Whether they can survive the duodenum, jejunum or ilium is another matter. I attribute "gas" to the fermentation of complex carbohydrates that pass into the colon where the native flora attempt to digest the sugars. Yeast has more of a laxative effect IME.

In which case Jim would seem to be on the right track in reducing those by lowering mash temps and crystal.  Wonder why he's not seeing any changes?  And the odd thing is that it seems to affect other people he gives his beer to, not just him.

[johnf]

I would expect yeast to survive the stomach. Acid washing is done for a couple of hours at pH 2.2 and that is about the pH of the stomach.

As for long chained carbohydrates, I think that is a red herring. Eating a bowl of barley should give you orders of magnitude more gas than eating the product of barley that has been malted and mashed which causes lots of reduction is long chained carbohydrates.