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You are here: Home --> Forum Home --> Brewing Forum --> Brewing Discussion --> Beer Diagnosis -- Sulfur / Cooked Vegetable

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chino_brews
Charter Member
Eden Prairie, MN
301 Posts


I'm trying to diagnose a sulfury or cooked vegetable aroma in a bottled batch of Dark Mild.

First of all, I have no idea what the difference between the two aromas is, and any guidance there would help. The aroma was basically a fart-like sulfur, maybe like cabbage cooked for a long time, and not a nose-stinging sulfur like volcanoes. The aroma was strong on initial pour, and then subsides enough so you can get malt, coffee, and fruity aromas, but a slight off-aroma is ever-present.

The beer had no perceptible off-aroma or off-flavor at bottling.

The yeast was a fresh pitch of Fuller's (Wyeast 1968), pitched at around 0.65-0.70 million cells / ml / °P (very slight underpitch). The grain bill was MO, GP, medium crystal, dark crystal, brown malt, English chocolate. No Pilsen malt.

Fermentation started at 64-65°F, and was warmed up to 75°F after a few days.

A few things went (or were done) wrong on this one: I left it in the primary fermentor for too long (4 mos.). Much of that time was spent cold crashing in the garage. The beer definitely froze solid at some point before bottling; in fact, I may have gelatin-fined into slush without realizing it. I brought it inside for 5 days and then bottled with CBC-1. At the time, the beer might have been underattenuated -- it finished at 1.012 instead of an expected 1.009 (off OG of 1.043), but the forced ferment only ended up at 1.010, so I wasn't worried about attenuation.

The other interesting factor is that the beer ended up overcarbonated - enough to start behaving like it was going to gush at glacial speed, and the beer was effervescent in the glass. This might be due to the underattenuation issue I mentioned, but might be related to the source of the sulfur.

My hypothesis is yeast autolysis, but I know for every 50 cries of "autoloysis!", there is probably only one actual case of autolysis.

Anyway, any ideas would be welcomed.




Posted 34 days ago.

homebrewdad
Charter Member
Birmingham, AL
2480 Posts


If you finished at 1.012 but had gushers and a sulfur smell, I wonder if you don't have bottle contamination.  4 months doesn't concern me; I've let beer sit that long and longer without an iota of issue.

How many bottles have you tried?  Have all had this?

Have you allowed a sample to go completely flat, then taken a gravity reading? 

I don't think this is autolysis.  Soy sauce, burned rubber, plastic... maybe autolysis.  Sulfur/vegetables plus gushing doesn't match, for my money.





Posted 34 days ago.

chino_brews
Charter Member
Eden Prairie, MN
301 Posts


Update: I tried a second bottle last night, but was too distracted by tax forms to bother getting the refractometer. Maybe tonight.

I think this bottle was lacking that sulfur character (but my mind is playing tricks on me). Beer is definitely overcarbed, and way overcarbed for the Dark Mild style: it starts foaming in the neck when you open it, although it didn't come out of the bottle even though I waited 7-8 seconds.

This beer poured clear, so I definitely think my friend poured the last one badly, and maybe that sulfur was yeastiness combined with CO2 and carbonic acid.

I'll do a better update next post.




Posted 34 days ago.

homebrewdad
Charter Member
Birmingham, AL
2480 Posts


Glad they may not all be gushers, anyway.  Please update when you know more!



Posted 34 days ago.

chino_brews
Charter Member
Eden Prairie, MN
301 Posts


OK, so after three more of these, I haven't gotten any more sulfur and those last three beers have been clear, so it seems it was an issue with the first bottle and that pour.

Each of the bottles is equally overcarbed. You'll see why below. When I open a bottle, there is not quite enough carb to cause a gusher, but the beer in the neck starts foaming and the released CO2 causes the yeast cake to get disturbed.

So I poured quickly. Then let it sit for a little over an hour.

Overcarbed, the beer is dominated by carbonic acid and effervescence. But allowed to go flat to proper carbonation levels, the beer is really, really good.

OG was 10.3°Brix (1.040). SG at bottling was 5.5°Brix (1.012). Current SG is 4.7°Brix (1.009). So it finished attenuating in the bottle.

FG at bottling was a little high, but I didn't do a forced ferment test because it was a mild, and I knew I alllowed the yeast (Wyeast 1968) plenty of time to finish. Around 5 days in the mid-60s °F, then about 3 days at 75°F, another three weeks or so at 68°F, and then about two months of cold crashing, if I remember correctly. I figured it was done.

Those three gravity points added about 1.5 volumes to a beer I already carbonated high for the style (2.0 volumes) because I was submitting it as a local entry in the NHC and expected the judges to ding me if I carbed it anywhere near cask-like.

Sans excess carbonation, the beer is outstanding, and I plan to open all of these 60-90 minutes in advance. Dry, flavorful with subtle malt complexity and esters, a barely noticeable touch of roast, hops softly and almost imperceptibly defining a bottom note, dry, crisp finish, and no astringency. It's exactly what I would have expected of a multiple GABF winning recipe (by Dry Dock), tweaked to be a little higher gravity and a little more malt complexity for the NHC.

Anyway, yet another NHC entry ruined by an easily-avoidable process error. That comp always brings out my worst, for some reason.




Posted 34 days ago.

homebrewdad
Charter Member
Birmingham, AL
2480 Posts


Well, crud at the error... but at least you figured it out.



Posted 34 days ago.

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