Long Lag Time Creates DMS?

I've read something to this effect in a couple different sources, but I want to confirm that one of the hazards of a long lag time is a serious DMS problem.

To point: I had a chocolate rye brown ale into which I re-pitched some 1056 that had been sitting in a quart jar under beer for about a month. No starter.

(I had not used a starter because my original starter just didn't smell right, so I went with the emergency plan).

I had also let the wort cool from about 70 to about 60 overnight in my fermenter fridge before pitching. And, because I was in a hurry the next morning before work, I didn't aerate.

Soooo...yeah...there are all my sins.

Needless to say, I had about three days before I had any visible signs of fermentation, and the fermentation was fairly wimpy, producing little krausen.

The finished beer has that wonderful overwhelming rotten cabbage/corn flavor (in addition to overpowering tannins from too much chocolate rye and roasted barley in the recipe).

Does this experience jive with others' experience? Will cold storage mitigate the problem over time? Have I learned my lesson and will always keep a package of Nottingham on hand?

Dimethyl Sulfide

Description: Tastes and smells of cooked vegetables/corn/cabbage or shellfish/seafood. Is acceptable in light lagers to a degree.

Cause: Bacterial infection can cause DMS, as well as covering up your brewpot during the boil. DMS is removed from the wort during the boil, so covering it up is obviously going to cause the DMS-laced condensation to fall back into your brewpot.

Remedy: Keep good sanitation procedures, and make sure to keep a rolling, uncovered boil when brewing. Do not cover your brewpot during the boil!

Well, a long lag time would allow for a bacterial infection, I suppose.

I've just read in a couple of places that DMS can result from long lag times. I'm wondering if the other poor fermentation practices (on my part - I can't blame the yeast) contributed.

Well, I wouldn't agree with the long lag time being the cause.

If it were then it would happen to a lot of people who don't make starters.

I'm thinking of John Palmer's note in How to Brew that diacetyl can result from long lag times...

...in this case, I'm starting to think that the DMS flavor is a bacterial infection that's hiding behind the astringent dark malts. I'm thinking the bacteria were able to get a foothold because the yeast got such a slow start.

I've also read it can be caused by covering up your brewpot and not letting the DMS boil off. Did you?

No, nor did the recipe have any pilsner malt.

I just noticed last night that in The Homebrewer's Companion, Papazian also attributes the cooked vegetable flavor to long lag times.

I have never seen any mention of DMS occuring due to long lag times, nor do I recall Palmer saying that. I've quoted info on dms for brewers and NEVER noticed anything about lag, just covering and bacterial. I could have missed something, but I don't think so. I've never come upon any issues with long lag times in yeasts. Long lagtimes are a natural occurance with some yeasts. Hence the sticky we have about yeast taking up to 72 hours to start.

This is what I know about lag time and DMS.

It has to do with boiling your wort and chilling your wort. At 210F its boiling out of solution, DMS seems to form in quantity between 140F and 210F. The trick is to crash chill as fast as possible to minimize DMS. I read somewhere that once you are below 140F you are OK. So if you are below 140F then the lag issue from 140F to 76F is mainly a concern about contamination. Pitch good and you are OK if its not too long of a time.

Another tidbit about DMS, is with pilsner malt. It usually has a higher potential to form DMS, so longer boils are better for pilsners, 90-120 minutes, more so important since they may be light in taste.

DMS can also occur while you're cooling your beer, even if your wort isn't covered. DMS requires heat to be produced (besides bacterial infection of course) and there is a range of temperatures where it's production is optimal. Don't quote me on the numbers, but I think it's in the vicinity 80C and higher. If you don't cool your wort fast enough, and your wort hangs around 80C for longer than it should, tons of DMS will be produced and will stay in your beer since you're no longer boiling to dissipate it. Do you remember if you took a long time to cool your beer?

A long lag time should not change the level of DMS in the beer (unless it is really hot or something). But, a long lag time can allow bacteria in the beer to take hold. Some bacteria infections can have similar aromas/flavors.

From Palmer:
"When caused by bacterial infection, DMS has a more rancid character, more liked cooked cabbage than corn. It is usually the result of poor sanitation. Repitching the yeast from an infected batch of beer will perpetuate the problem."

While a long lag time can be no problem, it can sometimes be a problem if there are bacteria in there (though a short lag time does not assure a clean beer). If you are certain that the boil/grist/cooling is not the issue, then I would look at sanitation. I would imagine that if it is infected, it will get worse with time. DMS from the grain will not.

I think the most common for DMS is the lid boiling mistake, and letting it sit hot for an hour or more. Hot being defined as flame-out no chilling whatsoever.

If its really foul, I'd say its infected. Assumes you made neither of these mistakes above.

I have also heard that DMS can be caused by bacteria, it can be a serious factor because your taste threshold for DMS is so low that a little bacterial activity during the lag time could be enough. I believe I heard this on the brewing network.

Like I said, I chilled down to about 80 or so, then cooled in the fermenting fridge overnight to 60. So it could have stayed relatively warm for a long period of time.

I'm not concerned about boiling or grist, so it could likely be a bacterial problem, due to the incredibly slow yeast growth (due to my lack of starter and aeration).

I don't have any other signs of infection, though, including over-carbonation.