The Vinous Deduction Theorem: A Guide to Blind Wine Tasting

This week I take to the road to facilitate a blind wine tasting event for the Friends of Italy Society of Hawaii. The Italians need their vino. Mobile Musings is on the job. Andiamo!

Wine is extraordinary complex. It is derived from a precise combination of biochemical engineering, terroir, climate and winemaking practices. Its raw material, vitis vinifera, has thousands of varietals. It is cultivated in over 70 countries, with thousands of designated appellations and subregions. The task of determining (without simply looking at the label) a particular grape varietal and its vinous origins might therefore appear a daunting and futile expedition.

Deductive tasting, however, has great benefits.

First, it is an excellent method to develop your palate and wine knowledge. Removed from preconceptions of what a particular wine's aromas and flavors "should" be, there is freedom to observe what is truly present. This also includes price, which the brain can translate into positive sensory pleasantness. In vino veritas. With time and practice, you will develop your wine knowledge database to determine what type of wine you are holding, how old it is, and its origins.

Second, it facilitates discovery of preferred styles, varietals, and regions. Drink what brings you joy, not what is popular.

Third, it is fun! Admittedly, it may require a certain level of wine geek to appreciate and enjoy this somewhat wonkish activity to its fullest. It does, however, afford great conversation with friends, and is an excellent excuse to break out a few bottles. Consumed in the pursuit of science.


But how do you do it?

Deductive tasting is wholly dependent on the senses. A systematic approach is useful to refine those senses and translate observations to accurate wine conclusions. This post provides a few tips to get you started on your journey of vinous cogitations. Remember, there is no “correct” approach; fashion a system that is effective for you. Taste, hypothesize, repeat.

The Vinous Deduction Theorem

Deductive tasting, at its core, is deriving conclusions from sensory analysis. This analysis is not linear; the senses must be utilized in conjunction with one another. The only tools at your disposal are your senses of sight, smell, and taste. Use them wisely.

As you traverse this post, appreciate the fact that the Master Sommelier Diploma Examination allots a mere four minutes per wine for deductive analysis! Taste fast, think fast.

Sight: Veni Vidi Vici

Visual inspection of the wine presents its first clues. Tilt the glass away from you, preferably over a white napkin or tablecloth, and observe the following:

Color. Color is proof of the wine's development (or age). White wine deepens in color through oxidation as it ages, while red wine becomes lighter in color over time. Color is also perceived in rim variation. The wine at the center of the glass is much deeper in color than the wine at the outer rim, with a large spectrum of color gradations in between.  While rim variation can be recognized in red wines of any age, both red and white wines display more variation in color with age.

Clarity. Clarity refers to the quantity of suspended particulates in the wine, and its ability to reflect or absorb light. It may be described as clear, slightly hazy, dull or cloudy.  Wine should possess clarity; otherwise, it may signify poor production or that the wine has spoiled. Cloudy? Proceed with caution...

Body. Body is determined by the amount of dissolved solids and viscous compounds contained in the wine. This can be identified visually by two variables: movement and viscosity.

Light-bodied wines (i.e., those with fewer dissolved solids) will move around the glass quickly when swirled and fall quickly down the inside of the glass once motion ceases. Conversely, heavy-bodied wines (i.e., those with more dissolved solids) are cumbersome in movement and fall slowly down the inside of the glass.

Viscosity is the extent to which a liquid resists flow or movement. The Gibbs-Marangoni Effect explains that a wine’s viscosity is the result of fluid surface tension caused by the evaporation of alcohol. Abundant alcohol causes sticky situations. This is colloquially described as “legs” or “tears.” A wine possesses good legs when it slowly slides down the glass, indicating a more full-bodied wine that contains higher alcohol and/or sugar content.

A lot to remember? Troubling news: this was the least important sensory analysis. The nose and palate dominate deductive tasting.

Upward and onward.

Smell: Olfactory Observations

Smell is king of sensory analysis.  While there are a mere five categories of taste (i.e., sweet, sour, bitter, salty and umami), humans can smell over a trillion odors. In fact, smell accounts for as much as 80-85 percent of the sense of taste.

In wine, as in life, there is a lot to smell.

Take an initial sniff. Next, swirl. Smell different? Swirling helps to aerate the wine, providing an oxidation effect that enhances the wine’s natural flavors and aromas. Aromas can be placed into a few broad categories: fruit, floral, wood, earth, spice and biological. It might be useful to have a diagram or chart for reference; for example, Wine Folly puts out a good flavor wheel. When judging aroma, be as specific as possible. Don’t settle for citrus when you smell lemon citrus; don’t settle for lemon citrus when you can smell lemon peel or lemon zest. Challenge yourself to go further. Be mindful of the strength of each aroma. Some aromas may be subtle, while others dominate the bouquet. This is an important distinction when considering potential varietals and regions.

Smell is more than just aromas.

Intensity. How intense are the wine’s aromas? Can you smell the wine from a distance, or are you struggling to extract aromas with your nose fully in the glass? Intensity of wine is an indicator of the grape varietal, which can be characteristically more or less aromatic than others.

Alcohol. When inhaled, ethyl alcohol molecules cause a warming sensation in the nose. A wine with relatively low alcohol won't significantly affect the nose, while full-bodied, alcoholic red wines may make the nostrils tingle.

Taste: Fusion of the Senses

At last, we drink! Commence with small sips and ensure that the wine coats all surfaces of the mouth. The palate will likely require a little time (and beverage) to adjust to the wine’s flavor.

Deciphering flavor involves the collective effort of taste, touch and smell. Taste sensations (i.e., sweet, sour, bitter, salty and umami) are detected by nerve cells within taste buds, located in the mouth and throat, that transmit information to the brain concerning the flavor of the food, or in this case, wine, being consumed. Simultaneously, food and beverage interacts with sensory cells located alongside taste buds that perceive tactile qualities such as texture, temperature, chewiness, astringency and pain (too many Thai chilis!). Finally, aromas that are detected through the sense of smell are relayed to the mouth through a process called olfactory referral. Hence, what you smell is what you taste.

Flavor. Time to break out the flavor wheel again. Tasting should confirm the aromas displayed in the wine. Additional flavors may also make an appearance. Similar to aromas, some flavors will be more pronounced on the palate, while others more subtle. Categorize the flavors you experience in the same way as aromas: such as fruit, floral, wood, earth, spice and biological. Flavors (and aromas) often change over time as the wine warms and is exposed to more oxidation. Continue to monitor the flavor profile as you journey through the glass to note shifts on the palate.

Sweetness. A wine’s sweetness is derived from residual sugar. Wines are commonly referred to as dry or sweet, and this of course runs a spectrum (dry, off-dry, medium-sweet, sweet, and very sweet).

Acidity. Acid is a vital component of wine, providing crispness, freshness and balancing the palate. Additionally, acidity can help to preserve the wine. The palate senses acidity by taste and touch. Acidity tastes sour or tart, and also makes your mouth water and causes a tingling sensation on the sides of your tongue and cheek. When in doubt, rely on feeling over taste for acidity, as winemakers can balance tart and sour flavors on the palate, masking their intensity.

Tannin. Tannins are polyphenolic molecules found in the skins, stems and seeds of grape varietals and also imparted to wine through interaction with oak during the barrel-aging process. Tannins can add necessary structure and complexity to wine, as well as act as a preservative that can assist in aging. For tannins, two observations are important. First, the level of tannins present in the wine and the corresponding level of astringency. Astringency is a tactile sensation that makes the palate feel dry and induce a pucker or tightening sensation. Second, the aggressiveness of the tannins. Are the tannins forward and overbearing? Or are they soft and velvety on the palate?

Body. The wine’s body is an indication of the level of ripeness in the grapes used in its production. If grapes are fully ripened, they will possess more sugar, solids, and viscous compounds, translating to a fuller-bodied wine. These wines feel thick on the palate and coat the mouth. Conversely, lighter bodied wines are a product of cooler climate, less ripened grapes, creating a thin feeling on the palate.

Complexity. Was the wine complex, presenting various different aromas and flavors that change as the wine travels across your palate, and over time?

Alcohol. Alcohol finds its way into sight, smell and taste. For taste, alcohol causes a warming sensation, especially near the back of the mouth and throat. A wine with too much alcohol will be described as hot. Does the alcohol taste and feel on the palate confirm your observations in sight and smell?

The Final Countdown

Finally, you are ready to assess the overall experience. How does all this information translate into a vinous conclusion? Remember, the goal of deductive tasting is to accurately determine: (1) the grape varietal, (2) the region of origin, and (3) the wine’s development, or age. There is no correct order for your methodology. This is a fluid process where you are analyzing many aspects of the wine at once, and confirming with one sense what you observed from another. As such, there is no need to analyze in a linear fashion. A few deduction tips.

1. A Variety of Varietals

Grape varietals are extraordinarily complex on a biochemical level. For thousands of years, these vitis vinifera varietals have undergone genetic manipulation and selective breeding. Winemakers excel at identifying and enhancing the chemical compounds and polyphenolics (often concentrated in stems and skins) that constitute certain desirable flavor profiles. Want grapefruit, apple, or lychee on the nose? There is a phenolic for that. The end result are varietals with defining and distinctive aromas and flavors.

When determining what varietal you have in the glass, all those aroma and flavor characteristics come into play. Once you note the aromas and flavors you find in the wine, it is time to peruse the mental card catalogue you have developed (or will develop) to match the corresponding varietal.

Tip: keep a real catalogue of your observations for reference. There is a LOT to remember, so create cheat sheets. Develop a format that makes sense to you, and helps you to remember important information about varietals and regions. This is an example of my digital catalogue.

Other factors include: climate (certain varietals only thrive in cool and warm climates), aging regime (whether it is aged, aged in oak, etc.), tannins (thicker-skinned grapes will almost always produce more tannic wines than those with thin skins), and pigmentation (red wines with thicker skins with produce more pigmentation).

2. Vinous Origins: From Whence It Came

Climate can be determined by body, acidity, and alcohol content. Warm climate regions benefit from longer growing seasons allowing the grapes to fully ripen. This translates to wines that have higher amounts of sugar, dissolved solids, alcohol, and less acidity. In cooler climates, like much of the Old World, lower temperatures preserve acidity but stunt the ripening process. As a result, cooler climates produce wine that is lighter in body, higher in acidity, lower in alcohol, and containing less sugar.

The wine world is broadly divided into two regions - Old World and New World - each with defining characteristics of flavors and aromas. The below table summarizes some key differences:

Musings by the Glass - Vinous Deduction Theorem - Old World New World Chart

The Old World is terroir-driven, resulting in wines that are characteristically more earthy and mineral-driven on the nose and palate. The New World, on the other hand, loves its fruit and oak aging. High acidity can also tilt analysis toward an Old World country, as there are many cooler growing regions in the Old World.  If the wine is overtly fruity without a trace of earthiness, chances are it's from one of the new world countries.

For regions, be as specific as possible, from country, to primary, secondary and tertiary appellations within that country (e.g., France, Burgundy, Côte d'Or, Côte de Nuits). Regional conclusions are immensely difficult and takes years of dedicated practice and study. Aim for one tier at first, and polish your skills over time.

3. Development: One for the Ages

From your observations, can you surmise the wine's age? This is evidenced by color (discussed above), aroma, tannin and sediment, among other things. For aroma, is the wine young and vibrant with fresh, ripe fruit dominating the aromas and palate? This showcases a youthful wine. Alternatively, is the wine filled with rich aromas of leather, vanilla, tobacco, and earth that are characteristic of barrel and bottle aging?  This tips the analysis toward an older vintage.

Tannins also evidence age. Young, undeveloped wines often have aggressive tannins. On the other hand, older vintages will seem softer; the astringency, while present, feels more velvety on the palate. Finally, sediment. Detection of sediment in the bottom of a glass is a good indication that the wine is developed. More sediment, more age.

Describe the wine as youthful (1-3 years), some age (3-5 years) or aged (5 or more years).

A lot to remember? Absolutely. Fear not; the process becomes more natural as you develop a systematic approach that works for you. In the interim, you get to drink a lot of wine. That’s not a bad day’s research.