Mine enemy, I know thy face and I dub thee "chloramine."
The tag line for this blog is "stumbling through homebrewing." Perhaps I wrote that with a bit of affected humility, as I thought I was doing a great job with homebrewing and I wanted to share how great of a job I was doing with everyone. But it turns out I was unwittingly stumbling the whole time. At least in one aspect, and probably in many more yet to be discovered.
A little over four weeks ago, I primed and bottled my Christmas beer: Ubupe (meaning "gift") Mint Chocolate Stout. I was very excited to pop open the first bottle this past Sunday, in hopes of sipping a lovely Christmas beer while bottling the Mpriripiri Mexican Chocolate Stout.
Didn't quite work out the way I wanted.
Why? Because the Ubupe was terrible. I don't think I've ever tasted a beer quite so awful, and I became acquainted with a fair amount of skunked PBR in my college days. This beer was the worst. Taking a sip of this beer was like gnawing on a rusty nail.
I was very disappointed, because I haven't succeeded in creating a truly enjoyable beer since my third batch, and I was hoping this would be the one that bucked the trend. But instead it was the worst yet.
After the initial period of angry frustration and feelings of hopelessness, I set out on a quest to figure out why my beer tasted like metal. Most of what I found just didn't seem applicable to my brew process. All of the usual sources limited the causes for metallic off-flavors to:
unprotected metals dissolving into the wort but can also be caused by the hydrolysis of lipids in poorly stored malts. Iron and aluminum can cause metallic flavors leaching into the wort during the boil. The small amount could be considered to be nutritional if it weren't for the bad taste. Nicks and cracks ceramic coated steel pots are a common cause as are high iron levels in well water. (How to Brew)
This just didn't make sense for my beer. My water did not have a high level of iron, my pot is sufficiently oxidized to prevent any aluminum from leaching into the wort, and anyways, if there was metal in my water or if it was a brew kettle issue, wouldn't I have tasted this before bottling?
My search was getting more and more frantic, since I was planning on brewing in a few short days and the last thing I wanted was to create another 5 gallons of undrinkable beer. A post on homebrewtalk.com yielded no immediate results, but as I was reviewing past posts concerning metallic aftertastes, I decided to take a closer look at my water.
Water. It's the single biggest ingredient in beer. And I had paid it no attention. The books I read actually TOLD me not to pay attention to water until I had mastered everything else. I read that sentence and I moved on. I missed the part that said don't pay attention to water, unless.....
Unless you have chloramine. Chloramine? What's chloramine?? It is apparently a relatively new form of disinfectant added to the public water supply. Chlorine has long been the de rigueur disinfectant/sanitizer, but its volatile nature (it will dissipate with boiling or even if you let your water sit out in a bucket overnight) caused problems for utility companies. This problem was solved by my newest enemy.
Chloramine in its natural state is a liquid, so it does not disperse naturally, even if you boil it. This makes it great for the public utilities, but awful for homebrewers. When chloramine interacts with the beer ingredients during the beermaking process, chlorophenols are formed. What are chlorophenols? Well, there is a scientific definition, but the laybrewer's definition is: things that make your beer taste terrible. And since the flavors come into being during the fermentation/conditioning process, you've very little indication of the fact that the off flavors are coming from your water. Chloramine is a stealthy sneaky killer of enjoyable homebrew.
Cholophenols also have a ridiculously low taste threshold. Their gag-inducing presence can be detected at as little as 10 parts per billion. Horrible.
But generally, off-flavors from chloramine are perceived as band-aid, medicinal, harsh, or astringent. Metallic is not the typical flavor. However, chlorophenols take different forms based on the other ingredients of the beer. Some are worse than others. I finally felt like I had discovered the true cause of Ubupe tasting like a 1970s VW rabbit tailpipe when I found the following on Wikipedia, under the chloramine entry: "Chloramines should be removed from water for dialysis, aquariums, and homebrewing beer. Chloramines can interfere with dialysis, can hurt aquatic animals, and can give homebrewed beer a metallic taste."
Aha! So how do you get rid of them? Easy peezy. Adding a quarter campden tablet (potassium metabisufite) to your brewing water and in less than a minute.... no more chloramine.
So with my latest enemy vanquished, I move on to my brewday, when I tried and mostly failed to brew a Belgian Golden Strong Ale. There will be more on this latest stumble of mine later, perhaps titled "The case of Why the heck is my efficiency 15 points lower than it usually is?"
Until next time, happy drinking!
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