Driving Miss DMS
My Grodsizkie (or Grätzer) is beige. That's not a color typically associated with beer making. However, it's not off-putting or all that unpleasant to behold, this smoked beer of mine.It's interesting, too, to produce a beer that doesn't look like all the rest.
The head that formed was only okay but I'm not too concerned about that and I'm certainly happy that it's not over-carbonated. In fact, I'd say I got the carbonation just right. It's fizzy, prickly, sprightly. I like that.
It's the flavor that I am concerned about.
But first the good: It's pleasantly smokey without overdoing it. It doesn't tip over into super-Band Aid smell or flavor, as some smoked beers do. It's light-bodied, semi-crisp and refreshing. There's no tartness but the dry finish contributes nicely to the beer's overall thirst-quenching qualities. The smoke is right on target, as well. I wanted a hint without hitting the drinker over the head with it. And I got that.
Now the bad: off flavors. I'd say there's a slight oxidation problem and there are some phenolics, not the clove kind I like, but rather, a plastic-like flavor and aroma that, while not totally awful, probably wouldn't win me any home brew competitions.
But the real offender is a tomato smell that reminds me of walking into a pizzeria.
A bit of research reveals that this is caused by something called Dimethyl Sulfide, which is more commonly – not to mention more easily – referred to as DMS. The presence of this compound in beer produces a range of unacceptable flavors and aromas, most notably a smell that recalls creamed or canned corn. If you're unfamiliar with DMS, here's an easy way to experience it. Go get a Rolling Rock. Open it. Pour it in a glass. Close your eyes and smell. That cooked corn smell is DMS at its finest.
But DMS can take other guises and in the case of my grätzer it produced a tomato-like essence. Which is weird to experience in a beer, to say the least.
How did this happen? Well, in doing my research I realized I made a really basic, silly mistake. Alas, it was a mistake that resulted directly from my moving to a smaller scale with my brews.
In my old five gallon set up I had to remain constantly vigilant about the threat of a boil over. So I watched my boils carefully. If the foam ever rose close to the rim of the pot, I could shut the flame down, give the pot a stir and calm things down.
With my new set up, boiling a few gallons in a five gallon pot, there's absolutely no threat of a boil-over. There's just way too much space in the boil kettle. That's a good thing, right? Well, yes, unless it makes the brewer absent-minded and allows him to leave the lid on his pot!
One of the reasons we boil is to drive off DMS. The unwanted odors and flavors produced by DMS are carried off over the course of the boil via the steam. It is often recommended that boils last 90 minutes for the very reason of removing this undesirable aspect of finished beer.
With my lid still on, however, the steam re-condensed and dripped back in to my wort. So much for removing the DMS. Instead of making a light, dry, refreshing brew I made a smokey, DMS-infused beer...ugh.
So keep the lid off your kettle and leave the cooked corn to the green bottled monster.Last modified on