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I’m getting a little geosmin in the nose


How useful and informative would it be for a wine consumer to learn from a critic that a wine has the aroma of geosmin? Not very, you’re likely thinking. You’d have to look it up, and even then, you’d suffer from a serious case of MEGO when learning that the proper chemical name for geosmin is (4S,4aS,8aR)-4,8a-Dimethyl-1,2,3,4,5,6,7,8-octahydronaphthalen-4a-ol, that “Geosmin is produced by several classes of microbes, including cyanobacteria,” and that “In 2006, the biosynthesis of geosmin by a bifunctional Streptomyces coelicolor enzyme was unravelled by Jiang et al.”

On the other hand, such information could very well be of enormous interest and value to a winemaker. If it is true that “Geosmin…is an organic compound with a distinct earthy flavor and aroma, and is responsible for the earthy taste of beets and a contributor to the strong scent (petrichor) that occurs in the air when rain falls after a dry spell of weather…” then it might be important for that winemaker to control for geosmin–to discourage or encourage it, depending on how much of that “earthy taste of beets” she wants in, say, her Pinot Noir.

In other words, there are at least two different methods to describe the aromas, flavors and textures of wine: one suitable for an amateur audience, and another for a scientific one. The two are light years apart. In my job, it isn’t in the least necessary for me to understand the ins and outs of geosmin, as long as I can properly describe a Pinot Noir as smelling like fresh beetroot (a favorite word of Michael Broadbent for Burgundy, and one I occasionally turn to, usually for certain Russian River Pinots). I do like the metaphor of “the scent of the air when rain falls after a dry spell of weather”; it’s almost poetic in its connotativeness. But I doubt I’ll ever actually use it.

These thoughts arose in my head when, by chance last week, I happened to read this article, in the latest issue of Andy Blue’s The Tasting Panel, about an olfactory expert, Alexandre Schmitt. He holds workshops with winemakers, in order to heighten their awareness and understanding of aromas. Among his clients mentioned in the article are Caymus, Harlan, Ovid and Cliff Lede. I was up at Ovid last Friday, where I spoke with their winemaker, Austin Peterson, about his studies with Schmitt, which have been going on now for three years. Later, at lunch, the topic arose again, this time involving another wine writer. The discussion grew a little heated when the other writer said that it’s important for wine writers to have a thorough understanding of very technical topics, including wine olfactics, in order to do our job well.

I couldn’t disagree more strongly. As I explained to the other writer, the winemaker and the wine writer have entirely different jobs. The winemaker must have a grasp of grape and wine chemistry (and many other technical fields) in order to do his job properly. (Austin, incidentally, is a very great winemaker.) Just as a NASA engineer has to be thoroughly grounded in everything from math, physics, chemistry and earth sciences to writing, public speaking, management and leadership, so the winemaker must be master of viticulture, enology, sanitation, oak barrels, machinery and equipment, pest management, employee relations, local ordinances and on and on.

The wine writer doesn’t need to know about any of that, or just minimally. Sure, a certain base knowledge of, say, rootstocks and clones is useful. Just how much, however, is an open question. Pinot Noir winemakers obsess on clones. Does 115 tend to ripen earlier or later than 114? Which is more tannic, 777 or 667? These are vital to the winemaker’s eventual success or lack thereof.

How important is it for a wine writer to know such things? Look at it this way. Let’s say I taste a Pinot that’s very tannic. That’s certainly important information to convey to my readers. But–assuming I even knew that there was a lot of clone 777 in there–how important is it for me to tell readers that the tannins come from 777? First of all, I can’t prove it, although clone 777 is generally associated with strong tannins. Let’s say the winemaker herself told me the tannins are from 777. Do I repeat that to the readers? Is it necessary or even interesting for them to know that? I don’t think so, any more than it’s necessary for the buyer of an automobile to know where the steering wheel was manufactured (political and economic considerations aside). A car buyer wants to know how the steering wheel feels in his hands, how the car reacts to turning it, what options in its material construction he has, if he can control the sound system without removing his hands from it.

A wine consumer similarly wants to know the basics: What does the wine smell like? What does it taste like? How’s the finish? Should he age it? What foods should he drink it with? Is it a particularly good value? Of course, depending on how much space the writer has to express himself, he can fit more or less information in there. If I have 250 words to devote to describing a single wine, I might well say something about the toast level of the barrels, or the soil composition of the vineyard, or even where the winemaker worked before. If I have only 40 words, my options are limited: I have to get the basic information across, and moreover in a way that’s well written. I might even be able to get a little poetry in there, a la “rainfall after a dry spell.” But no matter what my word count is, I can’t see the point of using a word like geosmin.

  1. Steve, I get your point; all of us want to distinguish ourselves, justify what we do, and separate one’s importance from the herd, it’s understandable. However, requiring a technical topics standard to writing about wine reviews, personalities, or geography is just another way of doing that with a badge of exclusivity of sorts. I concentrate on presenting a pleasing photograph with my parochial NH wine reviews, but it wouldn’t be appropriate to insist others do the same.

  2. Good wine descriptors require shared experience. A while back one of the other wine bloggers said good Russian River Pinot Noir has the aroma of tayberries. Not being familiar with this fruit, I was able to source some plants from a nursery on Puget Sound. While I wait for my dozen plants to produce fruit, I am putting out the following call: where in the Bay Area is there a market or stand selling tayberries?

  3. Bill Dyer: I wouldn’t know a tayberry if it walked up to me and slapped me across the face!

  4. Some experts insist that you can only call a wine earthy when it has a beet root aroma. Schmitt included.

    So, as a critic:

    1. you have to be able to detect and recognize geosmin

    2. appropriately call the wine earty

    3. understand what the presence of geosmin means for a) the provenance of the wine grapes b) production of the wine c) the taste of the wine 4) the future outlook of the wine

    So, YES, you DO have to understand the ins and outs of geosmin AND be able to accurately detect and identify it (more that 50% of the time). Or you are not an expert. Which means that if you are not an expert you do not belong in the position of a wine reviewer. At any publication. Period.

    You see, an expert would have written a piece about what gesomin is, how it smells, what it means for a wine and how a budding wine lover can learn to detect it and finally how you experience it and how readers can use that as a point of reference for themselves – instead of writing a piece about how geosmin (or rotundone, or geraniol, or alkylated phenols) is irrelevant.

    It’s good to know something about viticulture, but it is of greater importance, as a wine evaluator, to know enology and organoleptics.

    This would allow you to challenge or cast doubt on the winemaker’s assertion about 777 and tannins.
    You might apply your knowledge of the climate and farming methods (of that fruit, not another variety in an AVA 350 miles away) to further understand the above assertion about tannins in the particular wine.

    I recommend you start with one of Schmitt’s seminars. That is, of course, if you can handle him repeatedly telling you you’re wrong (as he is apt to do) and then try to understand and learn the system he is presenting.

    This would be the first step to being able to answer your posited questions:

    “What does the wine smell like? What does it taste like? How’s the finish? Should he age it? What foods should he drink it with? Is it a particularly good value? “

  5. Thanks for including the link to my article in your post, Steve.
    I do think it’s important to note that I write almost solely for the trade and my position reflects that. When it comes to writing for consumers, I agree with you most heartily.

  6. The statement that begs being made here is that there are different types (or tiers) of consumers.

    While they may not make up the majority, those at the top tier (or possibly upper two) DO want something more than being proposed. They do want the facts and not opinions because their understanding of wine is evolved to the point where they want more detailed and accurate info that is independent of the reviewer’s preferences and enjoyment.

  7. Thanks Deborah!

  8. as an assistant winemaker at a small winery, i often have discussions with the head winemaker about the value of science in the winemaking process.

    in his opinion, the more science you know, the better you will be at winemaking. i have a pretty basic understanding of chemistry, and it has indeed served me well in winemaking, so i wouldn’t 100% disagree with him.

    however, in my opinion, the better you are at winemaking, the less you need to rely on science. a lot of winemakers would disagree with me, and maybe i am opening the “natural winemaking” can of worms here…but who cares how many geosman phenolics you have in your wine? are you going to buy geosman extract and put it in your barrels? would that even make your wine better?

    i think that winemaking is more craft than science. you work with your hands to sculpt a wine, and you get the wine you get. some people use additives or enhancers or fancy machines so that the scientific readings fit into the parameters they believe are ideal. i would never say they are making wine the wrong way. but i certainly don’t believe in making wine that way.

  9. Dear gabe, thanks for weighing in from the perspective of a winemaker.

  10. I would agree in saying that in depth knowledge of chemistry in winemaking isn’t of value nor are clones etc. It would only if it categorically made a wine distinct or inherently better (both of which it does not).

    But what is often lost on most critics is lack of understanding the science of phenomonology and the basic science of tasting. If they did they’d taste less wine and be more accurate. Whenever a taste a wine that a critic missed on, I wonder why and its my guess that they are tasting incorrectly (ie mechanics when they call a wine “hot”) or they simply have numbed their taste buds.

  11. Zack, I got my B.A. in philosophy, and can’t quite see the connection between phenomonology and tasting. Phenomonology concerns the philosophy of consciousness, which is something I’m delighted to discuss. But what does that have to do with geosmin?

  12. Steve,

    In all fairness, the views expressed in my comments do not necessarily represent the opinions of any reputable winemakers. Like most comments on this blog, it’s just one man’s opinion. But I am lucky enough to participate in the winemaking process, and we spend a lot of time talking about the role of science in winemaking. I’ll admit that sometimes it is very helpful; but i often think it’s just a way for people to make themselves sound smart.

    If some guy is teaching classes on how to identify geosmin phenolics in wine, I start to wonder what the point is. Sounds like you might have the same response. I admit I am fascinated by clonal variation, and I understand why it might be boring to non-winemakers. But when I hear people throwing around scientific terms to make themselves sound like they know more than you about wine – especially tasting wine – I call bullshit. I mean, who cares what the geosmin levels are? Does it taste good or not, that’s what matters.

    Anyway, I thought your blog was great. Science is useful, but not necessarily superior. I’d much rather drink a wine that smells “like rainfall after a dry spell” then drink a wine with 42 geosmin units.

  13. Meanwhile, detailed scientific analysis of wines (for various reasons) is paying a lot of mortgages and college tuitions….

  14. gabe, thanks very much.

  15. Gee, Steve, I can’t imagine why you are ignoring the enlightened comments by SUAMW.

    I know that my neighbors would much prefer wine descriptions that talk about tayberries and geosmin than fruit and earthiness–or even beetroots.

    You are, of course, 100% right about what a winewriter with an audience of consumers should be about.

    SUAMW needs to create his own wine journal in which he talks to about 200 geeks who may not know what he is talking about but will love his line of B. S. a lot more because of it. As for me, I think I will stick with my own line of B. S. It seems to have served me and my readers well for three decades and counting.

  16. Geosmin results from an interaction of certain fungus and mold organisms present in rotten grape clusters. You expose your ignorance by suggesting that a winemaker might want to “discourage or encourage it, depending on how much of that “earthy taste of beets” she wants in, say, her Pinot Noir.” Geosmin taints wine. I challenge you to find a winemaker who would ever espouse its merits.
    As a wine writer, you should have a solid understanding and ability to recognize common wine flaws. That way you don’t sound foolish when a wine pisses on your leg and you describe it as rain.

  17. Dear Charlie Olken, you continue to be an inspiration to all wine writers. Thanks for the comment.

  18. Rick Kushman says:

    Steve and Charlie,
    Hear, Hear on you both.

  19. Maybe this is along the lines of using science to sound smart but a quick literature search on geosmin returns a paper published by the NIH describing geosmin’s degradation under acidic conditions. (E.G. may not responsible for earthy aroma’s in wine which is very acidic)

    As a winemaker, I use science every single day. Not necessarily the specific facts that can be quickly gleaned from a textbook, but being trained as a scientist to use and understand the scientific method. Accurate, reliabile, and repricatable data are critical to making better decisions in the winery. Aroma science is fascinating, I suggest as a resource for common food and wine aromas.

    As for geosmin, the drought has seemed to create an earthy smell in our water supply and I was looking into culprits. It may be the cause, but it will take a controlled experiment before I believe the issues with our water will not impact the outcome of our wine.

  20. Charlie:

    Because none are so blind as those that wont’ see….

  21. Charlie, the count on all of us is running out. You first, though….

  22. Steve,

    Didn’t realize you also have the most practical degree (see link below). There are quite a few others in the wine business: Randall Graham, Tony Soter, and Paul Draper are others that I know of. I got mine from UCSC. Maybe we should all be getting extra credit in Aesthetics. How about a column or blog- post relating enology and phenomenology?

  23. Steve,

    Thanks for providing an excellent counter-point to my opinion on the value of science in the winery. I have been accused of hating science, or not believing in science, but neither one is true. I have tasted many excellent wines made by science-based winemakers, and have never doubted the authenticity of their work.

    My only concern is when science based winemaking takes on a religious ferver of being the only way, or the right way, to make wine. It took a long time for Western Medicine to admit that there were certain ailments that could be better cured using less scientific methods. If it is true for medicine, I am sure it is also true for winemaking.

    And apologies if you took offense to the “using science to sound smart” comment. Like I said, I do a fair amount of scientific testing in my day job, and I understand its practical value.

  24. gabe, don’t worry about being accused of hating science. I get accused of hating social media!

  25. Bill Dyer, years ago I realized how many philosophy majors are winemakers. It would be cool to get a complete list.

  26. Somewhere I saw a statement that winemaking is a battle between science and art. I believe it was from a discussion about Burgundy and included a winemaker. Can’t remember the context exactly but the idea resonated with me.

    Perhaps wine writing is the same battle…too much science and you loose the mid-range and lower part of the audience, too much art and you loose the top end of the audience. The health and wealth of the wine industry depends on the whole audience, and according to plenty of research the top-end wine audience is only about 10% of the total wine market. Yes that 10% are addicts and represent serious power and dollars, but still. One fun yet surprising statistic is that 85% of wine consumed in US comes from 150 wine brands. Note the term brands and consider how many of those are real wineries or just labels.

    As alway Steve great stuff and often thought provoking posts.

  27. gabe: I know some great winemakers who never took a science class in their life. But their success is based on observation, and the ability to figure out cause and effect. In other words, they are empirical. Education in science is a very direct path to evidence based knowledge, but not the only path. The winemakers who I see getting themselves in big time trouble are the “magical thinkers” who have an ideology or pre-conceived belief system they feel compelled to promote. Come to think of it, this is a problem in the culture at large…

  28. bill,
    i totally agree. i actually use a lot science in my current winemaking, even tho i am always trying to depend on it less. like you said, it is important to use a diverse set of ideas. using no science and relying strictly on “natural winemaking” is as obtuse as using tons of science because it is the “right way” to make wine. in fact, i know a lot of people who are so focused on the results of their lab tests, that they sometimes forget to look at empirical evidence to the contrary.
    i guess my goal right now is to keep getting better at making wine. that includes learning more science, learning more natural winemaking techniques, and talking to people on wine blogs to enrich my knowledge. 🙂

  29. Ernie in Berkeley says:

    Tom: At least one winery uses the idea–petrichor–proudly: Petrichor Vineyards.

    Re phenomenology: so much cognitive science today describes how the mind creates meaning, and this is basically the same thing. A thick zinfandel on a winter’s night will taste different on a hot summer afternoon. That sort of thing.

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