With my
recent endeavor to become a Certified Beer Server (the first certification
level of the Cicerone Program), part of the study before the exam was to know
and analyze off flavors in beer. Now we’ve all had beers that we didn’t enjoy.
Maybe just a “Yuck!” or “Gross!” Besides crying about it, do we know exactly
what we didn’t like about them when we tried them? Was it a skunky beer? Was it
contaminated in some way? Could it be a brewing mistake? Or was it simply just
a weird flavor about the beer that you didn’t like? There are many things that
can affect the flavor of the beer, and understanding the different off-flavors
can help you determine what should be present and what shouldn’t.
My study
partner and I decided to put together a few experiments to help hone in our
off-flavor senses. We also added a few raw spices in the testing samples to
improve our senses of those as well.
Acetaldehyde:
Tastes and
smells like green apples. For this one, we just sliced up a fresh apple and
sipped a light commercial beer along with eating the apples. It’s very
contrasting to the normal flavor of the beer, so it’s pretty easy to pick up.
If your beer’s profile doesn’t have this flavor listed, then it’s not supposed
to be there.
Alcoholic:
This flavor
and aroma is exactly how it sounds. It can be compared to an acetone, or paint
thinner, and can sometimes be characterized as “boozy.” You know that warm fuzzy feeling after you’ve
taken a shot of Tequila? Yeah, this is the same thing.
Astringent:
A harsh
flavor that can make your face pucker. Can leave a dry or a grainy aftertaste. I tend to think of rubbing alcohol or a soapy flavor or smell with this one.
Diacetyl:
Buttery or
toffee aroma and flavor. Some people say there can be a “slickness” in the
mouth. We compared two glasses of a light commercial beer, one with a couple drops
of melted “I Can’t Believe it’s Not Butter!”
DMS (Dimethyl Sulfide):
Creamed corn
or canned vegetables; reminiscent of Thanksgiving dinner, but in a bad
way. In some rare cases it can also
resemble a shellfish or oyster-type smell (eeeewww). For this experiment we
just cracked open a can of creamed corn, and put a few drops into a glass of
light beer and compared it to one that hadn’t been contaminated. We,
unfortunately, didn’t have any spare shellfish to sniff.
Estery:
Fruity! Citrus, flowery……
Grassy:
Does your
beer taste like a leafy green salad? This aroma resembles the smell of fresh
cut grass; We obtained some from the lawn.
Metallic:
Have you
ever pricked or cut your finger and started sucking on the wound so you don’t
bleed all over the place. That tinny/iron taste that blood has is a good
example. Since we didn’t want to go that far, we decided to get some spare
pennies, and soak them in water. Yep, smelled like wet money!Oxidized:
Mmm…wet cardboard! That what oxidized beer may smell like. Also, can be characterized as papery or stale. For this one we did the obvious, soaked a piece of cardboard.
Phenolic:
I love spicy
food and even spicy beer (when it’s supposed to be). When it’s not, this off
flavor can be compared to a peppery or smoky flavor. Sometimes it even comes
off as “medicinal,” or band-aid like. Yuck.
Solvent:
Acetone or
paint thinner. We decided against the idea of sniffing paint thinner for this
experiment, but we all know what it smells like.
Sour/Acid:
Vinegar and
tart are the most common ways to describe this type of flavor/smell. Just
picture drinking the beer and then puckering your face. We
dumped some vinegar and lemon juice in a glass to taste and smell. Pucker face away…….
Sulfur:
We all did
experiments with sulfur in grade school science and remember how it smelled:
like rotten eggs. Can also be described as sewer or burning matches. Since no
one really keeps eggs in their fridge long enough for them to become rotten, we
just burned a couple of matches.
Yeasty:
Bready. My study partner happened to have some bread yeast
in her cabinets that helped us isolate this flavor/smell.
The Evil Skunk Beer
We have all
had a skunked beer probably way more times that we ever should. It’s so common
because it can happen so quickly; in as little as a few minutes. It happens
when beer is exposed to light, and is the reason why many brewers prefer to use
brown bottles, or even cans to prevent this from happening. When light is
exposed to a beer, it reacts with the hops to create a skunk-like flavor or
smell. Therefore, skunking tends to be worse in beers with more hops.
For this
experiment we grabbed two Heineken Lights, and put one out in the sun all day
(then chilled it right before serving), and kept the other in a closed
refrigerator away from any light. We poured them both into individual glasses,
and tasted the “non-skunked” one first. When comparing the two, only a slight skunky
smell and flavor was detected in the sun-baked beer. For the most part, they
tasted relatively the same. Heineken is pretty much known for its “skunky”
flavor and it has become an acceptable identity for the beer. Given that they
are bottled in light green bottles that provide little protection from light,
it’s possible that they had already been skunked at some point. It would be
interesting to do this experiment with a hoppier beer that’s in a darker bottle
to really compare skunk vs. non-skunk.
Summary:
These
expiriments were pretty simple, but very helpful in isolating these common off
flavors.
However, really
understanding off-flavors in beer also requires a more in-depth knowledge about
beer styles. Some specific flavors may be acceptable in one style of beer but
not in another. For example, the “buttery” flavor of Diacetyl may be acceptable
in a beer such as a Bohemian Pilsener, but not acceptable in a Traditional
Bock. It’s common for ales have the presence of a fruity (esthery) smell or
flavor but it’s important to know when it’s appropriate for the style.
These
off-flavors can be one of many culprits. It can be contamination while brewing,
storing, or bottling. Possibly even from using dirty equipment that wasn’t
cleaned entirely. They can happen with bad transporting or storage
practices. But before we go and generalize every beer we don’t like as a “bad”
beer, we need to do the research. Know the beer style, and know the beer
profile; and know that sensory evaluation is left to human interpretation that
differs from one beer drinker to the next.
