Winetasting Terminology - The Poetry and the Prose

Just over seven years ago I passed the Master Sommelier exam. Many people helped me in that endeavor, and after passing I made a conscious effort to contribute to others’ pursuits to become better wine professionals—whether through certification or personal journey.

My first realization in teaching the art of tasting was the need to objectify elements that could be consistently identified and easily taught… okay, maybe not so easily. I found that many of the heuristics that I relied on were all too individual, uniquely experiential, and frustratingly vague. How could I be a good teacher if I couldn't tell someone exactly where he or she went wrong and put my finger on how to achieve more consistent success?

I have always been prone to analogy—for better or for worse—and I like to think of the role of the sommelier like that of a doctor. We have imperfect information about a field more complex than we'd like to admit, and our role is to communicate to terrified customers who have an even more anecdotal concept of the topic at hand. We learned from our mentors what worked for them, regardless of the rigor of the methodology that led them to these realizations. Maybe Syrah makes your eyes water; maybe Sangiovese tannins attach to the roof of your mouth; maybe Grenache tastes like alluvial stones; but if all else fails, try leeches. Yes, leeches always seem to do the trick!

Clearly it was time to evolve.

This may not be obvious to the newest generation of wine professionals, but a decade ago there were few objective terms we used to classify a wine. When I passed the MS exam I had no idea what a pyrazine was and when I gave my first tasting lecture on identifying them in 2009 at the Rudd Roundtable, there were more than a few jokes—albeit lovingly—made at my expense. The next year we talked of terpenes, the year after thiols. This year it was phenols, and the jokes continue.  But ultimately, for many people, this approach resonates! Yes, if you use the terms incorrectly and confuse stem inclusion for pyrazines, you can look a little silly in attempting such precise terminology. But once you master identifying a host of objective elements in wine, you can become an impressively consistent blind taster.

Shifting paradigms never comes without assured danger. In our case, the worst of these present themselves when we confuse the prose of wine tasting with the poetry of sales.  We have no more business approaching the table with talk of pyrazines and thiols than a medic should open their bedside dialog suggesting the risk of cerebral infarction. What the patient wants to know is, "Am I going to live?" and what the customer wants to know is, “Will I like it?”

But just as is the case with the vocation of my endless analogy, this is no excuse for our profession not to develop precise jargon. We have to learn to use pedagogical terms accurately and draw upon these concepts to describe wine in a manner that resonates with our guests.

Before we progress to an exploration of technical wine terminology and its even more important analog of poetic descriptions, I'd like to make a final medical equivalence: our understanding of the objective world is constantly evolving. The basic assumption of science and medicine is that all knowledge is tentative. The chemical compounds presented in the below charts are as we understand today (along with my best correlation to the evocative language we can use to describe them). Ten years from now we will have undoubtedly furthered our grasp on the chemical causes and effective smells we encounter, but that shouldn't stop us from exploring the potential realities that underlie the complex perceptions that define our field.

Geoff Kruth, MS


The purpose of each of the charts below is to link the chemical causes of distinctive wine aromas to the potential descriptions we can use to describe these elements. Each class of aromatic compound is explained in more detail in our Science of Tasting Expanded Guide. While this guide is only available for GuildSomm website members, we feel it should be essential reading for any wine professional.

Special thanks to Madeline Puckette from for working with us on these graphics.

Fruit, flower, and herb:

  • Many fruity aromas and lightly floral tones are the result of esters. Esters are created by the interaction of acids and alcohol. They are often formed during fermentation and the specific yeasts and fermentation temperature may influence their character. Be careful not to confuse the lightly floral and fruity character of esters with the more distinctively aromatic terpenes.
  • Terpenes—specifically monoterpenes—are a diverse category of highly aromatic organic compounds that are produced by the grapevines themselves. Muscat, Gewürztraminer, Torrontes, and Viognier are known to be particularly high in terpenes while Riesling and Albariño contain moderate levels.
  • Pyrazines are responsible for many of the herbal aromas that we find in the Bordeaux varieties such as Sauvignon Blanc, Cabernet Sauvignon, Cabernet Franc, Carmenere, and Merlot. (Pyrazines in Malbec tend to be below the threshold of perception.) Be careful not to confuse their smell for that of stem inclusion. 
  • Thiols are technically synonymous with Mercaptans—they easily capture mercury atoms—but we usually use the latter term to describe an onion or garlic faulty character, while we use thiol in reference to the grapefruit or passionfruit notes you are likely to find in a Sauvignon Blanc or Grüner Veltliner.


Earthy aromas are perhaps the most complex to define in origin. They can be the result of microbial activity (often described as organic earth) as well as complex reduced sulfur compounds (often described as inorganic or mineral).  It was once assumed that earthy flavors made their way from the soil through the grapevine into the grape but modern science gives us a different—yet admittedly complex—picture.

  • Geosmin is an organic compound with a notedly earthy smell. It is produced by bacteria and is a major component in the smell of wet rocks after a rain when these organic compounds are volatilized into the air. The transmission of geosmin into wine is likely the result of compounds being directly deposited on the skins of grapes rather than being transmitted through the vine. 
  • Brettanomyces is a yeast that is naturally occurring and frequently found in a winery environment. An individual’s tolerance and taste for brett is highly subjective. It can be a defining character in many "old world" style wines as the result of a winery’s stylistic tolerance and not of any inherent terroir
  • Volatile Acidity is a byproduct of microbial metabolism. Acetic acid bacteria (used to create vinegar) creates acetic acid, the most common form of VA. As it requires oxygen to grow, reductive environments and SO2 usage limit its presence. It can be a stylistically positive note in many classic oxidative wines such as Barolo or Rioja.
  • When we think of sulfur and wine we are often assuming the elemental form of S02 that is added as an antimicrobial and anti-oxidant. However, many reduced sulfur compounds are created as the result of fermentation and other complex chemical interactions. Low nutrient musts and low pH environments (high acid) may encourage some forms of reduced sulfur that are often described as chalky or flinty and can be an important component of cool climate wines such as Chablis, Sancerre, German Riesling, and Champagne.


The spice of wine can come from both varietal fruit character as well as the influence of winemaking and oak aging. Distinguishing between the two can be an important factor in blind tasting.

  • While lactone esters can be present in grapes, their major impact in wine comes from oak aging. Vanilla, hazelnut, and coconut are common descriptors.
  • Rotundone is an aromatic sesquiterpene (for you geeks, they have three isoprene units while our floral monoterpenes have two). It is most associated with the essential oils of peppercorns and culinary herbs like basil and thyme. Syrah and Grüner are the two most iconic grapes which are high in these compounds but other lesser-known varieties such as Mourvèdre may showcase this aroma. Winemaking techniques such as filtration can have a major effect on reducing their levels.
  • Botrytis cinerea is a fungus that affects fruit following damp conditions. While most famous in sweet wines, they can also affect dry wines. Ginger, chamomile, honey, and saffron are telltale aromas and it is a common feature in the wines of Alsace, Austria, Germany, and the Loire Valley.
  • While we have previously mentioned the effect of thiols in fruit driven aromas like grapefruit, these compounds can also be responsible for some meaty or coffee like aromas expressed in red wines. Research is currently limited here, but we expect to see more links between thiol levels and certain spice character.

The charts and subsequent notes presented here do not represent an endpoint, but rather an ongoing dialogue. They are by no means exhaustive and we can imagine more charts in the future linking other classes of compounds to potential descriptions. This dialogue and our understanding thereof will continue to improve, and sommeliers can become better professionals if we expanded upon both the poetry and prose of wine-tasting.