Sensory assessment is like a foreign language. It can be learned (and mastered). If you listen to people speak a language with which you are not familiar, you can't distinguish one word from another. Your brain, being unfamiliar with the sounds and their groupings, has no reference point and so it can't identify the words. Wine tasting is a similar experience when you are a novice. More often than not, it is unfamiliarity that limits one's full sensory experience of a wine.
It is important though, to first understand how one's sensory equipment works and how to use it. Many people speak of “the palate” as a sensory tool. Typically, by this they mean the tongue (and its taste buds) and the nose (and its olfactory receptors). However, taste buds and olfactory receptors are only that: receptors. They are detectors of chemical molecules found in and emitted by all things around us. They relay their raw data to the true sensory organ: the brain.
The receptors in the human nose are located far away from the nostrils which draw in aroma-laden air. It sits just under the front part of the brain, between your eyes. Animals known for their acute sense of smell have their receptors closer to the nostrils and in more direct exposure to the flow of inhaled air. For this reason, humans need to inhale deeper to sense aromas. Finally, the human olfactory epithelium is quite small. While there is some specialization of receptors, there is no map that can be useful to the wine enthusiast. While there exists some variation in sensory acuity, anosmia (total loss of on or all aroma) or hyposmia (reduced acuity), together, are present in about 1% of the population.
The brain, the ultimate organ of sensation, has areas that register the signals from the tongue and nose detectors and recognizes them as "sweet", "bitter", “coffee”, “smoke” or “roses”. There is one more level of perception and processing of sensory information that takes place in the brain and that has to do with enjoyment, pleasure and, ultimately, preference. The difference between recognition and the third, enjoyment-related, level of perceiving a smell is best illustrated by the smell of spoiled milk: we all can recognize it, we know what it means, but very few among us enjoy the aroma. All that being said, our past experiences frame and impact our current perceptions. (How else would we know the milk is spoiled?) Learning the smells typically found in wine can open up a whole new sensory world. Much like learning a new language, this learning process can be fun and rewarding.
For those who want to delve deeper into wine appreciation, a review of the immediate environment can help identify things which may limit one's ability to perceive wine aromas: smoking, strong perfumes and colognes, scented lotions, potpourri, incense or other air fresheners can overpower and overload the sense of smell. When one uses strongly scented products on a regular basis, not only does one become unaware of them, but these products, when present in large amounts, dull the sense of smell. Eliminating these things from the tasting environment can be very helpful in learning sensory assessment of wine.
Aroma actually makes up much of the sensory impression of a wine. Smelling a wine may seem second nature, but keeping in mind the facts about the human sense of smell outlined above, experts in wine assessment actually use a system to smelling wine. To get the sensory raw data to the brain (so it can learn and recognize the aromas and flavors) remember: Swirl, Sniff, Sip, Swish, Slurp and Spit.
Swirling is a big part of wine assessment and is serves a purpose. It coats the inside of a glass with wine and increases the surface area from which the aroma molecules can escape. Simply pour an amount equal to about one shot glass of wine into a wine glass. Put the glass on an even, smooth surface (a table) and grip the stem of the glass just above the foot. Make slow circular motions with the glass, keeping its foot flat on the table while the wine dances up the insides of the glass. Just a few turns are enough to coat the inside of the glass with wine. With time you will swirl like a pro.
Most people will instinctively stick their noses right into the glass. There is nothing wrong with that. However, depending on the composition of the wine (as well as the temperature of the wine and your surroundings and the humidity), some aromas may be detectable with the glass some distance away from the nose. A good place to start is with the rim of the glass at the level of one's chin (left, in the illustration below). Draw in air through your nose, slowly but deeply. Aromas detected at this distance are called "intense" in the context of the redwinebuzz.com wine assessment approach. Swirling again, bring the rim of the glass to your nose, but keep your nose out of the glass and sniff again (middle, in the illustration below). Aromas detectable at this distance are called "medium intensity" in our system. Now, swirl some more and put your nose into the glass and sniff again (right, in the illustration below). Let the rim touch the bridge of your nose but don't scratch your glasses. Also, be careful not to take any wine in through your nose as this can ruin your fun. We call aromas detectable this way "light".
You can do this while reading tasting notes from a source you like, or by comparing what you smell to a wine aroma kit or whatever reference aromas you have on hand. Note how the aromas differ from and how they resemble the reference aromas.
So now, as anticipation has built, and you want to take a drink. Take a sip and let the wine spill out over your tongue. Gently swish the wine around your mouth. The idea is to coat the tongue, your gums and the insides of your cheeks with the wine. This distributes the wine over all surfaces which can tell you something about it. Additionally, it allows the chemistry of your mouth to act on the wine. The wine may be affected by this interaction and you may find some unexpected sensations. Astringency is the major sensation not related to flavor and is typically felt on the insides of the cheeks and on the gums. Some perceive a heat or burning sensation of alcohol throughout their mouth.
We can taste only five things with our tongue: bitter, salty, sour, sweet and umami (a savory, meaty character). Contrary to common beliefs, there are no individual taste buds specializing in specific flavors, There also are no clearly demarcated regions which specializing in detecting one flavor. Rather, some regions of the tongue respond more than others to specific flavors or profiles by virtue of their representation in the brain. Thus the idea of a "tongue map" or "taste map", which dates back to 1901, has been tested, challenged and disproved over time. Nevertheless, some people assert they can taste flavors as indicated by this map (the tip of the tongue registering sweetness with greater sensitivity than other areas, the back of the tongue reacting most strongly to bitterness, the sides being more sensitive to acidity and the areas towards the middle detecting saltiness with most sensitivity). It is important to understand that different researchers have put forth, at times, quite varying "tongue maps". Despite much research data validating the existence of umami, there is no clear localization of this flavor and some suggest that sensitivity to it is quite even over the entire surface of the tongue.
There is a notion of a "super-taster" - a person capable of identifying more flavors and at lower concentrations than the average person can. This notion, suggests that, as with many things, smelling and tasting ability is spread along a continuous spectrum. While your tongue may just have a lower density of taste buds and your nose may have a different distribution of receptors (sensors) this does not eliminate the possibility of you learning to identify aromas (and flavors) as long as you have a healthy brain. After all it is the brain's memory and recognition of the signals from the taste buds that ultimately account for our ability to smell and taste.
All "flavor" sensations, besides those mentioned above, are the result of aromatic compounds making their way as vapors up the back of the throat (nasopharynx in the illustration to the left) and up to the nasal cavity and finally to the olfactory epithelium. This is demonstrated by pinching the nose or inhaling through the nose while swishing wine in the mouth. Chewing on a piece or apple an then a piece of uncooked potato while pinching your nose is another way to see this. In addition to astringency, our tongues tell us about the sweetness, acidity or bitterness of a wine. Finally, there is a general sense of body or weight of the wine we can perceive as it sits in our mouths.
As mentioned before, the enzymes and acidity of our mouths change the nature of some of the compounds in wine. The pH of the mouth affects the aromatic compounds in wine. In the mouth, alcohol is reduced as it is diluted by saliva and even absorbed a bit through mucosal membranes. All these things change the physical behavior of aromatic compounds. A way to tease out these changes as well as more subtle aromas is called aspirating - or more simply put: slurping through the wine. This may seem odd and maybe even comical at first thought. Have no doubt, though, this is how the pros assess a wine and it's called "retronasal olfaction".
After swishing a bit of wine in our mouth, lean your head forward and purse your lips as you would to whistle. The wine will collect in a small pool behind your lips, and in front of your tongue (which you should pull back). Slowly, draw some air in through your lips, letting it percolate through the wine (see illustration on the right). Then, keeping your lips closed, exhale through the nose (illustration above). Some prefer to swallow their wine before exhaling, which is fine, but remember to keep your mouth closed until you finish exhaling. With some practice, you will see that this method brings out some aromas you did not notice previously. Again, this is a result of the chemistry and temperature of your mouth acting on the wine's components. the aromas of the wine as well. If you are going to try this for the first time, anticipate getting messy. Wear something dark, keep your face over a table and watch out for the linen and the carpet.
These techniques are essential to assessing a wine in a professional context. Certainly, you wouldn't do this in a fine restaurant (or any restaurant) or the first time you meet your in-laws. However, these methods represent a systematic approach to training yourself to recognize sensory elements of wine and judging its quality. With time, you will also find yourself using these techniques less formally simply because you will more readily identify aromas, flavors and textures. As with language, once proficient, you can understand a whisper as well as a shout.
To help you learn to identify aromas, there are commercial kits of essential scents available from several producers. However, these may be too expensive for some and the less expensive ones tend to be of poor quality. Jelly beans or a scented oils may be an option, but remember that these are often scented with artificially produced substances that may not accurately represent the aroma in question. A more economical (and fun) way to get around that is making a trip to a local specialty grocer for the more exotic aromas and flavors. Using these items as reference points for aromas can help train your brain to recognize smells and tastes. Some may choose to skip this approach and simply compare their sensory findings with tasting notes on a site like this one.
All these techniques and the understanding of how our senses work can help one become an "Informed Sensory Observer". A sensory observer uses knowledge and experience with aromas, flavors and textures in wine as hallmarks of style, growing and production methods, quality, longevity and food friendliness.