OP
OP
Yes it's stainless. Both your suggestions are on the list, it's getting long, though, thanks for the input.
I have really only mashed at about 1.25 Qt/lb, so maybe next batch I'll try a thinner mash, though I know many peole have mashed at 1 Qt/lb without any problems.
There are some great comments and advise here and it appears you are well on your way pursuing these in an attempt to solve your problem. I have a few things to add that might be helpful.
In terms of it being DMS, I don't think this is your problem in that the flavor of DMS is more vegetable, corn like and sometime sweet. And how you might get DMS from a 60 minute boil versus others who get none from a 60 minute boil has to do with how long it takes to cool your wort after boil. Hot, non-boiling wort continues to form DMS and without a boil, it is not as readily driven off. Thus it builds up in the wort. The cooler the wort, the slower the reaction is in forming DMS. So if your wort was sitting at 180 F for 30 minutes and another brewer cooled his wort to 68 F in 30 minutes and both boiled for 60 minutes, your wort would have a much higher DMS level in the wort and beer compared to the other brewer.
The flavors you describe, sour, astringency, feusal (I assume fusel not fecal) can have different origins. The sour flavor can be from acid producing bacteria which is a contamination. Astringency is normally from the tannins in the grain. I see you are sparging with 190 F water and you said you have lowered that some to prevent extracting tannins. You might check your sparge water pH. Tannins are acidic so sparge water above 7 will solubilize and extract more tannins. If your sparge water is slightly acidic ( less than 7 such as 6.0 - 6.8), you will get less tannin extraction. Also, as you sparge the grain, the pH is rising to that of the water the more you rinse. Don't worry about getting maximum efficiency as the last bit of extract can come with a good shot of tannins.
Fusel oils are can be formed by yeast or bacteria during fermentation. If your fermentation temperatures are above 70 F you can get fusel oils from yeast. However, it sounds like you control your fermentation temperatures well so would not suspect this to be a problem.
One other thought is that an array of off flavors can come from hydrolyzed yeast. This can be a bitterness that is more lingering and different than hop bitterness. This happens when the beer sits on the yeast and/or settled yeast that has hydrolyzed is stirred into the beer somehow. This is a nasty after taste in beer. Do you carefully rack the beer off the yeast cake after primary and secondary fermentation?? Just a thought.
I hope this helps some. Keep up the detective work, you will find the problem!
Dr Malt
Thanks, I'm always careful with everything you mention. I literaly kill the burner and turn on the chiller, andd my 50' 5/8" imersion chiller never takes longer than 10-15 minutes to get the wort down to pitching temp. I always rack quietly, and almost never let a beer sit on a yeast cake more than 3 weeks.
I only recently checked my final runnings, and they were at 1.018. considering that all the beer I have brewed recently has had a very similar grain bill/mash consistancy/sparge volume, I doubt that the gravity has been more than a few points off of that reading within the last year.
I will try this if I have to, but I'm skeptical. My off flavor problem tastes nothing like the typical DMS flavor described above. Like millions of other brewers I aggressively boil for 60 minutes, and chill rapidly. Why would I have DMS problems?
