Lager Problem

Anyone have this issue before? I conditioned/lagered my beer in a glass carboy not realizing the airlock was plugged up. It lagered for a couple of months then the other day I kegged it. Needless to say it was a difficult transfer because it was highly carbonated due to the fact the CO2 had not been escaping. But the taste and smell were horrible. I don't know how to describe it. I thought it smelled like sulfur, my wife said rotten veggies. Notwithstanding the possibility of infection, what off flavors would be associated with this kind of error and is it fixable by letting it lager more but this time allow the CO2 to escape?

Some lager yeast are bad for sulfur. It should go away. A couple of months should have done it. Keg it and purge the keg a few times over the next few days. The CO2 will scrub the sulfur out to the top of the keg.

I definintely think that letting it lager longer will allow the gasses to escape and it will improve, unless you have an underlying brewing / fermenting problem, then it might not go away.

brian320fo said:

Needless to say it was a difficult transfer because it was highly carbonated due to the fact the CO2 had not been escaping.

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Clearly you used a lager (pilsner) yeast strain (which is a good thing when making real lagers). Lager yeast strains develop a lot of sulfur (especially the first few days of fermentation), it will smell really bad rotting eggs. Most frequent mistake when making a lager (and I think this is what happened here) is cold crashing or contitionning the beer too soon once the fermentation appears to have stopped. I made quite a lot of lagers and the "trick" is to raise the temperature to ale temp fermentation for few days to a week only once the FG is attained (that is usually after 3 weeks but it depends at wich temp your were fermenting). Because even if FG is attained and you see no fermentation activity, the yeasts continue to eat up sulfur that was created at the beginning of fermentation (that is why you need some yeast in your secondary too). If you try to conditioned the beer too soon after reaching FG, the sulfur will stay in the beer. And it really will smell and taste bad. The fact that you had CO2 in your carboy says that fermentation was not even finished. And the fact that the airlock was plugged up prevented Co2 and sulfur to escape also. No wonder you got a lot of sulfur. Another good trick (the best I think) is to taste the beer before you try to conditioned it. That way you make sure that sulfur is gone.

Now, can you save your batch? There is 2 ways you can try to save your batch (in fact 3 ways but one, given the probable size of your batch, is more expensive than starting new again). You can try to flush the sulfur by adding co2 then flush it then put some back then flushing again and repeat that until sulfur is gone (but sometimes it doesn't work). The second method is to add some sugar and repitch with new yeast (that will eventually eat the sulfur). But my experience says that it is much more work than starting over a new batch. If you follow these fermentation temp, you will not miss. 1st week around 10°C, second week raise to 12°, third week raise to 14°, fourth week raise to 18°C and even if fermentation appears to have stopped, wait until your beer does not taste sulfur before conditionning it. Because you used lager yeasts at low temp the first 3 weeks you beer will have the character of a real lager not of an ale.

Cyclman said:

I definintely think that letting it lager longer will allow the gasses to escape and it will improve, unless you have an underlying brewing / fermenting problem, then it might not go away.

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I guarantee it won't go away because he got too much sulfur in it (because he describes the odor as horrible which means a lot of sulfur) and sulfur is not a gas. Sulfur is not a gas but it can be flushed by Co2 gas. But with the quantity of sulfur he has he would need a lot of Co2 and multiple flushes. This happened because he tried to condition it too soon. Flushing sulfur from a lager that kept the sulfur for couples of month is a very difficult task to my experience.

Thank you or the replies. You're right about conditioning too soon. I've put an airlock on my keg to try to let the CO2 flush out the sulfur. I'll let it sit for a couple of weeks and see what happens. It's already considerably better than last week but still not drinkable. Thanks for the lagering tips, lessoned learned.

brian320fo said:

Thank you or the replies. You're right about conditioning too soon. I've put an airlock on my keg to try to let the CO2 flush out the sulfur. I'll let it sit for a couple of weeks and see what happens. It's already considerably better than last week but still not drinkable. Thanks for the lagering tips, lessoned learned.

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No problem. It has more chance to work if you flush the Co2. Let it become flat at room temperature but dont stir it otherwise you will put oxygen that will trigger the chemical precursor (acetolactate) that will eventually add more bad taste (too much diacetyl in your beer). Then put your keg under Co2 again (work best if you cool the keg first), shake the keg to force Co2 into the beer (around 10 psi). Let the Co2 out again at room temperature (but don't stir or shake it!). You repeat that until most of the sulfur is gone enough to your taste. Hope it will work!