- Created on 29 September 2011
- Written by Brianna
So let's break down in a little further detail, what, exactly, you're sniffin' for. Aroma is used mainly to describe the smells made by the malt, as well as any fermentation byproducts. Malt has an almost savory sweet smell; it's rich and complex and full of character, compared to, say, a cotton candy or kool-aid aroma, which can be produced when using sucrose, or cane, sugar. The difference between what type of sugar is used in your beer, as you know, is very important to the aroma, and, ultimately, the flavor, of the beer. Different malts smell differently due to having been kilned for different lengths of time and/or under different conditions. A black-as-night stout, made with chocolate and other dark, roasted malts, is going to taste roasty and toastier than a light lager, made with Crystal and Pale malts. They look different for the same reason.
You'll notice that I mentioned aroma is also derived from fermentation byproducts. This starts with the yeast and can be produced intentionally by specific strains of yeast many times. A great example of this is the famous Brettanomyces strain of yeast, which creates sour flavors in beers. This sounds kinda funky – and it is – but it's actually something that you'd sometimes want in some Belgian or wheat styles.
Maybe the most exciting aspect of a beer's aroma is the bouquet. When you're discussing or describing the bouquet of a beer, you're usually referring to the aroma that comes from what many would consider the MVP in the aroma of a great beer, the hop. Hops are that little miracle plant that imbue their bitter properties to your beer, balancing out the intense sweetness of the malt.
The third aspect, the ugly stepsister, really, is the odor of your beer. Just like it kinda sounds, odor does not usually indicate a good aroma. Odor is a foul sounding word reserved normally for any foul (coming from an infection) smells coming out of your beer. That being said, there are some instances where certain odors are part of the style or are at least acceptable in certain amounts. So it's a good thing you still have your BJCP Style Guidelines handy. You'll find within the style description an expectation of what, exactly, you should be experiencing in the aroma of a beer. Cause remember – some odors can be acceptable in some beers or in certain amounts – nothing is set in stone in the brewing world. Come to think of it, that's what makes it such a great hobby – the opportunity for suggestion, inspiration, and going with the flow.
In any case, without further ado, let's look at a few of the aromas that you may experience in
Taste/Odor Wheel. It's laid out in an outline format, which I always find a little easier to deal with than the actual wheel, but you can find the wheel itself easily online. We're just working with the aroma keywords here, so let's take a look.
- Alcoholic: Fusel. Can be an aroma and mouth feel. Reminiscent of wine.
- Fruity (strawberry, grapefruit, banana, raspberry, apple and pear)
- Acetaldehyde: Flavor and aroma of green apples. Budweiser deliberately creates some acetaldehyde
2) Resinous, Nutty, Green, Grassy
- Resinous (sawdust, resin, cedar, pine, spruce, seasoned wood)
- Nutty (brazil nut, hazelnut, walnut, coconut, sherry-like)
- Grassy (fresh cut grass, straw)
- Grainy (raw grain, husk-like, corn, grits, flour)
- Worty (fresh-wort aroma)
- Caramel (caramel, toffee, treacle, molasses)
- Burnt (burnt sugar)
- Phenolic (scorched, hospital-like, pharmaceutical, bakelite)
6) Soapy, Fatty, Diacetyl, Oily, Rancid
- Fatty acid (tallowy, goaty, cheesy)
- Diacetyl (butter, butterscotch)
- Rancid (rancid butter)
- Oily (vegetable oil, gasoline, machine oil)
- Sulfury (rotten egg)
- Sulfitic (burnt match, choking, burnt rubber)
- Sulfidic (sewage, natural gas)
- Cooked Veg. (overcooked greens, cooked corn)
- Yeasty (fresh yeast, meaty)
8) Oxidized, Stale, Musty
- Stale (old beer)
- Catty, light struck (skunky)
- Papery (cardboard)
- Moldy (damp cellar, wet soil)
9) Sour, Acidic
- Acidic (pungent, sharp)
- Acetic (vinegar)
- Sour (lactic, sour milk)
This is a pretty basic break down. Below, I'll go into a little more detail on a few of the common aromas.
Alcohol: this aroma creates a hot spicy sensation in the nose. Wines have a very strong alcohol, or vinous, aroma.
Diacetyl: A taste like butterscoth; go grandpa style and buy a bag of Werther's Originals to acquaint yourself with this flavor. I've also heard that Sam Smiths Nut brown ale has a low level of diacetyl in it. A good example of an off flavor that is still acceptable in some beers. When it is unwelcome in the beer is when it's been caused by things like poor cleaning of your equipment, under pitching your yeast, or adding too many adjuncts.
Dimethyl Sulfide (DMS): This is the aroma of cooked vegetables and corn, so hit the kitchen for a sample. This is not a happy flavor in your beer, and can be caused by slow cooling of your wort. Your Mr.Beer kit's process naturally avoids against this with the addition of cold water to your 4 cups of boiling water. It's an equation designed to bring the proper temp for pitching your yeast ever time. Bonus; you won't have to worry overmuch about this off aroma.
Light Struck: This can happen to any unprotected beer, any time it's exposed to light with a wavelength between 400 and 500 nm, or, basically, ultraviolet light. The light causes a photochemical reaction within the hop resins in the beer, and creates an unmistakably skunky aroma. To acquaint yourself with this aroma, all you've got to do is leave a beer out in the sun for a few hours. Your homebrew is most likely protected in brown glass or plastic, an why would you want to waste a homebrew anyway?, so we'd suggest a commercial beer in a clear or green bottle. It won't take too long to get skunky, and it won't take you too long to decide you want to do everything in your power to avoid this unpleasant aroma.
Oxidation: This is what'll happen if you use matl that's too old, or let your beer sit too long before drinking it. It's the smell of damp cardboard, which you should be able to reproduce pretty easily – use the cardboard box from your last Mr.Beer shipment even! This odor happens when oxygen combines with the beer and forms fusel alcohols, and it's never a good thing in your beer.
Phenolic: This is the hospital smell. My least favorite, in case you were wondering.....but I digress. It's a medicinal, or sometimes clove or smoke-like smell. It can come from clorophenols in your water, so always remember that water is an important factor in beer's flavor. Bottled spring water, unfiltered and mineral-rich, is best. However, this is one of those aromas that isn't always a bad one: you'll find it in some Belgian beers purposely for the clove flavor.
Solvent-like: This one's no good all around,. But I probably don't have to tell you that. You know hat a solvent-like taste is: it's acetone, lacquer, nail polish remover, and it's awful. It'll come to visit if your fermentation temp is too hot, so always make sure you aren't fermenting your beer any hotter than the required temp. It can also come from certain wild yeast strains, so just one more reason sanitation is key!
Sulphur: The smell of rotten eggs; I'll leave it up to you whether to try and sample this particular aroma or not. It can come from the degradation of your yeast or autolysis, which will happen if you leave the beer in the keg too long after the fermentation has finished. Always bottle as soon as the fermentation has finished if you can. For a rule of thumb, three weeks is about the maximum time you'd ever need to leave your beer in the keg – it's the longest time a fermentation will ever take, given the proper temp. It can also be caused by poor storage or contamination, so always be vigilant, which is a good closing thought, as it turns out.
I guess we've ended on a bit of a asour note - pardon the pun - so here's a last thought I'll leave you with. Dont' be alarmed at the amount of off flavors that can occur in your beer. You'll most likely never have to experience any of them. Especially if you are vigilant about your sanitation, and your process. It's just a good piece of information to know, like knowing where your safety vest is stored during your transatlantic flight. Focus more on the good aromas.