Green apple flavor sounds the most palatable of the
five, but I've never had the opportunity to have green apple flavored beer.
According to Parker in the article "Understanding Yeast Off-Flavors",
a green apple taste results from too much of the compound acetaldehyde.
Normally the yeast consumes acetaldehyde. However, if there is a problem
with the quality of the yeast or if too much sugar is added to the wort, it
might not do its job completely, leaving a cider taste to the finished product.
An apple taste can also mean the beer is too young and the yeast has not had
time to metabolize the acetaldehyde. (Zymergy, Nov/Dec 2012)(Palmer, 2006).
Astringent taste brings to mind nail polish to me,
but apparently there is a difference in astringent tastes and nail polish
tastes. Astringent is described by Palmer as being like “sucking on a tea bag.
It is dry, kind of powdery”. Extra tannins are the most likely culprits for
causing astringent tastes. Excess tannins can be a result of: over-steeping
grains, having a mash pH of more than 6, alkaline water (in cases with hoppy
pale beers), using too-hot water, or over-sparging the mash (Palmer, 255-256).
Nail polish smell or taste is probably caused by
ethyl acetate. Although ethyl acetate is a member of the sometimes-desired
ester family, it is unpleasant in high quantities. Ethyl acetate can be a
result of: excess wild yeasts, high temperature during fermentation,
under-pitching, and unnecessary oxygenation (Parker, 26).
There is really nothing like popping open a cold
beer (or warm, if you are like Stephen) and taking a deep, long whiff of rotten
eggs. Really, it sounds awful. Luckily, I’ve never had the pleasure. If you are
brewing a lager, don’t worry. Just let it sit for a couple of weeks and try it
again. Many lager yeasts actually produce hydrogen sulfide, which is the
culprit for the rotten egg smell, during fermentation. It should go away in
time. If you are not brewing a lager, then you may have a bacterial infection
(Palmer, 252). Go to the doctor and get a prescription…ba dum ching! But
seriously, sanitize, sanitize, sanitize!
Recently I had a craving for Newcastle. I bought a
6 pack, brought it home, popped it open, took a drink, and it was suddenly as
if I’d been sprayed by a skunk. The suspect? Newcastle’s clear bottles. Brown
bottles protect the contents from UV rays, but green and clear bottles leave
the beer open to lighting. Sunlight and fluorescent lights cause a
photochemical reaction in the hops, resulting in a skunky smell and taste
(259). A little bit of skunky taste in a light beer is fine to me, especially a
Mexican beer. It’s probably even intended to taste slightly skunky. But if your
beer smells like road kill, you might think about switching to brown bottles or
storing your clear ones in a dark place.
Finally, for our main problem: Metallic tastes. It
turns out that there are many different causes of this problem. It could be
because of the metal from the pot you were mashing in leaching into the mash.
It could be from malts that weren’t stored correctly. It could be from high
iron content in the water (258). I have also heard that it can be caused by
high chlorine content, which would make sense considering we’d been cleaning
all of our supplies with bleach.
Whatever the cause of our metallic flavors, it has
persisted to a small degree. We’ve bought filtered water, stopped cleaning with
bleach and switched solely to StarSan, and our malts our always stored in a
safe place. We have not had any of the other tastes I’ve mentioned as of yet,
although Stephen says our new Irish red has a very slight cidery taste.
Hopefully our research will prevent any unpleasant surprises in the future.
References:
Palmer, John J. How to Brew: Everything You Need to Know to Brew Beer Right the First Time. Boulder, CO: Brewers Publications, 2006. Print.
Parker, Neva. Understanding Yeast Off Flavors. Boulder, CO: Zymurgy, Nov/Dec 2012. Pgs 25-27. Print.
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