Could this be DMS in an ale?

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Well-Known Member
Jul 30, 2014
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I have been fortunate enough to have only made one beer in 25+ years that I have had to dump, not including the exploding bottles incident of 1995 that we will not talk about today🤣 I think the second one just happened. Both beers had a few things in comment namely a strong start (within hours) but slow finish to fermentation, very turbid appearance, and an aroma that I just cant place, but is very off putting. Having reviewed all the characteristic of off flavor descriptions, it does not at remind me of green apple, buttered popcorn, baby vomit, rotten eggs, etc) perhaps a tad sulphery but not all like hydrogen sulfide, which I familiar with from lagers during primary. There is notable off smell, could be convinces that it might be vegetal, not creamed corn, but a slight but sulphery. If you take a sip with out smelling it isn't noticeable on the tongue, but if you swish the beer around in your mouth it seems to release the aroma and the off flavor is noted in the palate area. Could this be DMS?

Other than this, these two beers couldn't be more different.
One was a dopplebock made with Munich, CaraMunich, and Carafa malts, boiled for 75 min, fermented with 34/70 (slurry repitched from an Oktoberfest that came out great). Fast fermentation start (OG 1.077), slowed to a finish (FG 1.018) over 2 weeks and was racked to bulk age for about a couple months. I has planned to make an Eisbock out of half of this and was concerned, but after the freeze distillation, this off flavor was gone. The original doppelbock remain off and was eventually dumped after about 3 months in a keg to let it age out. Fermented at 62F (warm lager, same as the Oktoberfest and many others with 34/70 I have made).

The current problem is an Altbier. A mix of Pilsner (60%), Munich, Cara, and Carafa malts, boiled for 60 min, and fermented with 1007 (made starter, pitched slurry only). Same fast start to fermentation (OG 1.053), then stalled at ~1.030 for a few days, gave it a gentle stir, and then it crept along for another 2 weeks to finish right on target FG (1.013). Transferred to keg at 20 days and noticed aroma. Fermented at 62F.

Neither had any visible signs of infection, stable fermentation temps, sanitation procedures have been effective today (wash, rinse, starsan soak). No sours or wild fermentations took place on the equipment in between batches. 10 batches of beer were made in between these brews on the same equipment, fermenters, hoses, fitting, and kegs with no issues. On was even a Bohemian Pilsner that is one of the best beers I have made (that used slurry from 34/70 after this years Oktoberfest)

Here are the only commonalities I have found. Both brewed in September (possible environmental contaminate?), both used yeast slurry (one from prior batch, one from fresh starter). Both started strong and than finished slowly. Both were cloudier than usual after fermentation (I hear this is common for 1007, but not 34/70).

I did check pH of finished beer an am at 4.6 (calibrated meter with a 4.01 and 6.86 right before test). I chilled a sample overnight, and it cleared up considerably with a ton of yeast sediment. This showed a minor reduction in off aroma, but not the fix. I aerated a sample which released a ton of this off aroma, but the resulting beer still has noticeable levels.

Can anyone place this pretty crappy description of an off aroma flavor? Does it sound like DMS? If so, may try the CO2 scrub technique. Anyone think this sounds like something more sinister that should be dumped with out efforts to save or age?