To come up with a review I think will be useful and informative, I go through three stages, and I'll take these in turn over the next three days: tasting the beer, assessing the beer, and finally describing it. Let's start with the tasting.
Look at the Beer
Your eyes can tell you a lot. If you pour a beer from a bottle, you can see its viscosity as it comes out, its level of carbonation, and whether or not yeast dribbles out at the end. These are useful clues. A thick, gloppy beer is one with lots of residual sugars. Carbonation levels may be a clue to style or brewing method. Does a head come easily or do I have to pour quickly to rouse one? The yeast indicates bottle-conditioning, which doesn't say a lot about the beer, but is better at preserving it. (If I don't see any, I look in the bottom of the bottle to see if there's any residue).
It's a bit more difficult if you get a draft pour, but you may see some clues in the head. Nitro heads produce bubbles so small the head is like cream (think Guinness). Cask heads are often quite flat, and you may even see just a skiff of largish bubbles. A flat cask pour may mean we're past the expiration date--or just that it's not really fizzy. Some cask pours use a "sparkler" which gives a nitro-like head, which can be confusing.
Of course, there are obvious facts about how a beer looks. Color will give you clues about the malts. Some beers are brewed to be pretty, and it's nice to pause a moment and appreciate. But there's a lot more information than color. Clarity is a big one. Haze could come from hops, proteins, or yeast (and the nature of the haze could be a clue to which). If a beer is especially clear, that's also telling, too. In some cases, breweries filter out any large molecules, leaving their beer very bright but often with less flavor-imparting floaties.
I keep looking as I'm drinking the beer. I swirl and watch the head structure. Does it stick around or vanish? I look to see how light refracts though the glass as the level goes down. I see if it remains effervescent--does it hold a bead? My eyes may lie to me, but that doesn't mean I don't use them. I can put meaning to my observations later.
Feel the Beer
One thing I hate is overly cold beer--and mostly draft beer is overly cold. To combat this, I try to warm my pint up with my hands. I usually am able to get it toasty by the time I reach the bottom of the glass--60 degrees or higher. This isn't ideal for many styles, but looking, sniffing, and tasting as a beer warms can tell me a lot about what's in it. Even over-warm, I'm getting interesting data.
Smell the Beer
For me, the most important part of the process is smelling. Human taste is dictated largely by what we take in through our nose. Plug your nostrils or sample beer with a bad head cold, and you can't really taste it. I've found that if I stop to really sniff and snort the aroma of a beer (provided it isn't too cold), it will help guide me to flavors when I taste it. Very often, the clues I pick up in the nose tell me what to look for in the flavor. In particular, I run through an inventory and try to assess each of these dimensions:
- Hops. Hops contribute all kinds of aromatics, and later, when I taste the beer, the aroma will tell me something about when they were added. I'm getting fairly adept at identifying hops, so I sniff to see what kind they seem to be. To the extent possible, I try to differentiate the various compounds--the citrus, pine, spice, flower, and so on.
- Malt. Malts and grain offer more subtle smells than hops, but they are generally evident. Again, sniffing to see if I can find nuts or toast or tobacco or coffee can be useful later on.
- Alcohol. Alcohol isn't an aroma so much as a chemical property--it vents off a beer with a sharp, umm, alcoholic quality. (This is an example of the difficulty of description, which we'll discuss in more detail in part three.)
- Yeast. Are you about to taste a Belgian dubbel, a NW amber, or an Oktoberfest? Sometimes your nose can tell you what your eyes can't. When a yeast is lagered cold, it produces low amounts of chemical compounds. But the warmer the fermentation temperature, the more esters, phenols, and "character" yeasts produce. In Bavarian weizens, a chemical called isoamyl acetate makes a banana flavor--a dead giveaway. Phenols are peppery or clovey. And esters can be fruity or spicy. Of course, soured beer has lots of different characteristics, and a "barnyard" aroma suggests one kind while a vinegar aroma suggests another.
- Off-aromas. Mostly these should be absent in commercial beer, and identifying them is hard if you don't brew. Guides are suggestive, but I didn't understand them until I'd screwed up a batch of my own.
- Adjuncts. Not all adjuncts can be smelled, and some can only be smelled. But if you think you're getting a blackberry note, take heed--it could be blackberry.
Taste the Beer
Finally we come to the tasting. And with me, it is honestly a "finally"--I may spend a couple minutes or more inspecting and sniffing. Because of that, tasting is in some ways the easiest part. If you swish a beer around aggressively in your mouth, it gives you a better sense of mouthfeel and causes vapors to go up your nose. I do that and usually follow the first sip up quickly with another one to give the flavors a chance to build.
With any luck, I've picked up some of the signals that guide me along my tasting. This can also be a moment of surprise; sometimes scents or sights mislead. Maybe the lush hop aroma disguises a low-bitterness beer. Or maybe a very bitter beer failed to exhibit much nose. Some qualities, like those given by yeast, are more perceptible on the tongue than nose. Essentially, though, I'm going through the same process, tasting for identifiable qualities.
After all of that, I begin to have confidence in what I've tasted. It's a slow process, but something about having hundreds (thousands?) of people reading what I observed makes me strive for accuracy. Of course, even with that, I sometimes miss things. But this process seems to work pretty well.