Wednesday, April 4, 2012

Fat Blocker

Red wine, fruit compound could help block fat cell formation

A compound found in red wine, grapes and other fruits, and similar in structure to resveratrol, is able to block cellular processes that allow fat cells to develop, opening a door to a potential method to control obesity, according to a Purdue University study.
Kee-Hong Kim, an assistant professor of food science, and Jung Yeon Kwon, a graduate student in Kim's laboratory, reported in this week's issue of the Journal of Biological Chemistry that the compound piceatannol blocks an immature fat cell's ability to develop and grow.
While similar in structure to resveratrol – the compound found in red wine, grapes and peanuts that is thought to combat cancer, heart disease and neurodegenerative diseases – piceatannol might be an important weapon against obesity. Resveratrol is converted to piceatannol in humans after consumption.
"Piceatannol actually alters the timing of gene expressions, gene functions and insulin action during adipogenesis, the process in which early stage fat cells become mature fat cells," Kim said. "In the presence of piceatannol, you can see delay or complete inhibition of adipogenesis."
Over a period of 10 days or more, immature fat cells, called preadipocytes, go through several stages to become mature fat cells, or adipocytes.
"These precursor cells, even though they have not accumulated lipids, have the potential to become fat cells," Kim said. "We consider that adipogenesis is an important molecular target to delay or prevent fat cell accumulation and, hopefully, body fat mass gain."
Kim found that piceatannol binds to insulin receptors of immature fat cells in the first stage of adipogenesis, blocking insulin's ability to control cell cycles and activate genes that carry out further stages of fat cell formation. Piceatannol essentially blocks the pathways necessary for immature fat cells to mature and grow.
Piceatannol is one of several compounds being studied in Kim's laboratory for its health benefits, and it is also present in different amounts in red grape seeds and skin, blueberries, passion fruit, and other fruits.
Kim would like to confirm his current finding, which is based on a cell culture system, using an animal model of obesity. His future work would also include determining methods for protecting piceatannol from degrading so that concentrations large enough would be available in the bloodstream to stop adipogenesis or body fat gain.
"We need to work on improving the stability and solubility of piceatannol to create a biological effect," Kim said.

Thursday, March 1, 2012

genius thinking

VINOGRAPHY: a wine blog

Wine and food 03.01.2012

What Wine Drinkers Can Learn from Leonardo Da Vinci

da_vinci_self.jpgAs some of you know, I was in Napa last week at theSymposium for Professional Wine Writers. The keynote speaker was Michael Gelb, the best selling author and speaker, whose most popular book How to Think Like Leonardo da Vinci, served as the primary subject for his talk. Gelb is a passionate wine drinker, who also has written a book called Wine Drinking for Inspired Thinking, so a talk on creativity from him didn't come entirely out of the blue. Even though wine was not his subject, he wove several wine anecdotes into his speech.
His talk was focused on using the principles outlined in his book to help those in attendance with their work and career as writers. But it struck me that these principles, which Gelb gleaned from Leonardo's writings and works, are a wonderful map for aspiring wine lovers. So with Gelb's permission, I'd like to explore how Leonardo Da Vinci (as interpreted by Gelb) can teach you a deeper appreciation for wine.
From Da Vinci's life and works, Gelb distilled seven principles that he feels embody "genius thinking." Each offers something to the wine lover.
According to Gelb, Da Vinci was "the most curious person that ever lived." He wanted to know how everything worked. Everything. And so he sketched, recorded, jotted, and obsessively chronicled his ideas, experiences, and questions in his notebooks.
A wine lover without passionate curiosity is like a couple that unfailingly has sex once a month in the exact same position without any foreplay. You're missing out on a world of opportunity! Tens of thousands of grape varieties, scores of different countries producing wines, thousands of winemakers around the world with their own vision for how to achieve the particular alchemy that transforms grapes into something divine.
If you truly want to learn about wine, and fully enjoy it, you not only need to drink widely and experimentally, but you also need a bit of Da Vinci's childlike wonder. A passionate curiosity ultimately results in a more conscious and thoughtful interaction with the world, and when it comes to wine, a much deeper appreciation and connection with what is in the glass.
Da Vinci was famous for his experimentation and his desire to demonstrate his own knowledge to himself. Many of his drawings come in triplicate, as he looked at something from three different perspectives.
One of the best ways to deepen your experience and knowledge of wine is to take adavinci_hands.jpgstructured approach to tasting it. While this shouldn't be your primary way of engaging with wine, because after all, wine is about pleasure, taking a methodical approach to tasting can be incredibly educational. In my essay, The Five Stages of a Self Education in Wine, I urge budding wine lovers to hold blind tasting parties with friends, where everyone brings a wine that meets a specific criteria (say, Merlots under $30) and tastes them blind, making notes, choosing favorites, and then talking about the results. These kinds of structured exercises not only bolster an understanding of, for example, what Merlot tastes like, but also help to hone your own preferences. How can you feel confident about your opinion of Merlot as a wine when you've never carefully tasted twenty of them from five different countries?
According to Gelb, "The Italians have la dolce vita, or the sweet life. The French have joie de vivre, or the joy of life. What do we have in America? Happy Hour?" There are different ways of being in the world, and different ways of thinking about how to live a good life. Da Vinci thought that man's senses were the gateway to the soul. This principle is about approaching life like the miracle that it is.
You're eating a cherry. Do you ever stop yourself mid-bite and think, "Now wait, I must remember, this is what cherry actually tastes like" with the idea that you'd like to be able to recognize it the next time you taste it in wine? My buddy Gary Vaynerchuk got a lot of mileage out of sucking on rocks with Conan O'Brien, but do you actually know what wet rocks taste and smell like? Wouldn't life be that much more interesting if you did? OK, maybe not, but remember that point above about curiosity?
Gaining a deeper appreciation for wine doesn't always have to come from paying more attention to how it tastes and smells, but damn, isn't one of the most amazing things about wine the fact that it can smell and taste like everything from lemon zest to smoked bacon?
Being attentive to the sensations of the world, its flavors and smells, its textures and tones, is a celebration of the miracle that we have the ability to perceive these things in the first place, as well as a source of deepening pleasure in our own existence.mona_large.jpg
But even as we revel in our experience of the world, it is impossible to understand and apprehend everything. The world is a big, confusing, mysterious place, and not everything has a perfect explanation. Sfumato is a term from painting, a specific technique that Da Vinci mastered that literally translates to "smoky," which produces a hazy mysterious quality that seems to glow with illumination. If you've seen the Mona Lisa in person, you will remember the curious softness of the light and lines, yet the beautiful sculptural quality that emerged from these seemingly imprecise applications of paint. Gelb uses this technique as a metaphor for a willingness to embrace the unknown and live with confusion.
How exactly does a wine's flavor change with age? What role does oxygen play in that evolution? What is the relationship between the chemistry of the soil and the flavor of the wine? Science has not been able to answer these questions definitively. Wine is mysterious even to those plumbing its molecular depths. For those of us who merely drink it, the mysteries are even deeper. We don't actually need to know how it is that a wine can taste of mint and chocolate, we can just appreciate it. It is enough to celebrate the complexities that older vines bring to a wine without knowing exactly why they do.
Life's a mystery, so drink up.
Arte e Scienza
Art and science. Left brain and right brain. Da Vinci's life work represented the pinnacles of achievement in both aesthetic and scientific pursuits. Engineer, painter, sculptor, inventor, musician -- Da Vinci embraced many disciplines and worked in many domains. Gelb believes that a key to unlocking our potential involves thinking and working across the spectrum of disciplines, as we might say at my alma mater, from the fuzzy to the techie.
Wine clearly exists at the intersection of art and science. It is equal parts of each. Without science there is just vinegar. Without art, we have flavored alcoholic beverage. Learning about and loving wine means embracing both of Thumbnail image for da_vinci_vitruvian-man.jpgits sides: understanding how it is made, while at the same time appreciating it for something more than just the product of photosynthesis and a set of chemical reactions.
Apparently, Da Vinci was not only a great inventor and artist, but he was also widely known as the strongest man in Florence. According to Gelb, he was a juggler, a fencer, a thespian, and a cook. The principle of corporalità represents the balance of mind and body , the equilibrium captured so deftly in Da Vinci's famous vitruvian man drawing.
When it comes to wine, this principle has clear implications. Wine is food. In the wrong quantities, it is also poison. Intoxication makes up part of the joy of wine, but anyone who has dealt with substance abuse knows the dark side of that coin. In sensible moderation, wine is, as Benjamin Franklin is often quoted, "a constant proof that God loves us, and loves to see us happy."
"Everything is connected to everything else," says Gelb, "which is why we have to be systems thinkers." Da Vinci made cognitive leaps all the time, grasping at connections between phenomena that had yet to be understood by the science or the religion of his time. For Gelb, this principle is not only about the connectedness of everything, but also about our own individual connection with our highest aspirations and purposes, and with each other.
Wine ultimately embodies connection. The connection between the earth and the sky, or as Galileo so beautifully put it "wine is sunlight, held together by water." The connection between man and earth, and the cycles of cultivation unbroken across millennia. And of course, the connection between people, brought together as they break bread and sip the fruits of their labors and their lands. Wine has always dissolved barriers between people and exposed us to our common humanity. Drinking wine together both celebrates our interconnectedness, and forges those bonds even tighter.
adventures in San Francisco and around the world

Tuesday, February 7, 2012

Is this a seventh or tenth sense?


Smell is a suave, elusive, sensual sense

Hans Schnier, protagonist of one of Heinrich Böll’s novels, used to smell perfumes, aromas and scents, a mix of absolutely intangible fragrances, impossible to transmit and to distinguish even in presence of the source itself

by Paola Cerana

In high school there was a time when I got fond of Heinrich Böll. Also literary passions follow season and today I would not feel the same emotions I felt back then. Still, there is one novel from Böll who remained impressed in my mind. The title is “Opinions of a Clown” and I remember that after reading it in my still bad German, I read it better in Italian.

It is a rather melancholic story lasting for only three hours. I was inexplicably fascinated by the idea of squeezing so many reflections, expressed over some hundreds pages, in so few minutes. The story per se is static, with no action, but full of emotions, deeply nostalgic and leaning towards a depressive spirit that still attracts me in an almost morbid way.

The protagonist is Hans Schnier, a young clown from Bonn who locks himself in his apartment following the umpteenth social failure, and surrenders to a painful and self degrading self pity. He goes mentally through his disappointments and frustrations, to which he feels to be condemned forever. The most painful is the deep romantic setback with Maria, whom he loved and lost, because of the attraction of a bourgeois world which she felt much more attracted to than a sad circus tent. Hans can just seek refuge behind is colored mask, without any hypocrisy and let himself be surrounded by suffered memories, while indulging to an emotive decadence in a vicious alcoholic circle. I still have the final image of the novel clearly printed in my mind: a grimace of make-up against the grey of a sidewalk, with his collar up and his hat in hands, to beg for smiles…a sad clown, grotesquely camouflaged in an equally sad carnival.

The book is actually rich in social implications which can help to judge. However, what attracted me most and still fascinates me today is the psychological underground and an expected quality of the miserable clown. Hans had the mystical prerogative to smell through the telephone. When he took the phone in his desolate flat, Hans not only heard a voice, but also smelled perfumes, aromas and scents, a mix a mix of absolutely intangible fragrances, impossible to transmit and to distinguish even in presence of the source itself. It seemed to be a nonsense, a paradox, that a young man who relinquished to enjoy life could grasp in such a way the essence of life itself, the primordial and animal signs of existence: scents!

The smell is a suave, elusive, sensual, powerful and involving sense, right because of its pheromonic action which seduces and inadvertently induces.

This painting like image of Heinrich Böll’s novel is even more attractive today, after amassing knowledge in psychology and neuroscience. I am attracted to the bizarre idea that, maybe, somebody can actually live this sensorial experience. Somebody with such a refined and sensitive sense to be able to decipher codes in the air, which are not perceivable by most, even at kilometers of distance and through complex technological tools. Maybe, if such a sense existed, it would not just pertain to the olfactory sense, but to a more complex and intricate neural network, where manifold sensorial organs would be entangled, including neurons, neurotransmitters, synapses, and who knows what else…

And I ask, then, if also the pronounced world, beyond the written one, can transmit scents, which can be perceived by people who are particularly gifted with this receptivity?

The question is not that mischievous. It could happen that an email or facebook message, would release smelling particles in the air from the monitor: tobacco, coffee, chocolate, jasmine, sandalwood, mandarin, mint, cinnamon, all through the communication transmitted from far away, and by means of a meaningless keyboard, projected in a wall of pixels, which can divide bodies but unify souls, as a hypnotic virtual veil.

I confess that this happens to me, at times, and I am sure it happens to some of you too! It happens that you read messages and smell scents which fills the atmosphere, or sharp aromas, or bubbling perfumes, all coming from the vortex of written words and rhythmical prose.

If this a seventh or tenth sense, an ingenuous suggestion of the mind or a magic charm of the heart, I do not know. Still, I know the fascination of following sensations towards a shared, more tangible and less virtual “elsewhere”. A dimension beyond logics and reason, aimed at capturing the soul of a person who writes to us from far away, with kindness, passion, irony, desire, embarrassment, excitation or love. Written words transmit the scent of the writer much more than a voice in a telephone or headset. This scent can change your mood and it can be imagined and shared if we learn to “feel” through the heart.

A lightly honey scent accompanied this lazy fall day, a day which appeared colorless but suddenly acquired a taste. I do not known if this is thanks to the memory of a novel of my youth, or some lines which came unexpectedly out of my monitor…but this was a sweet and growing olfactory “intoxication”, which is still lively and that I would like it to never disappear.

If some smell sensitive soul, like me and poor Hans, happened to read my delirious lines, I would understand if he turned up his nose at this absurdity! However, he should not worry about bad smells: my words would just leave an innocent a candid talcum underground scent with a vanilla aftertaste, mixed with a bit of fire red pepper, to stimulate the slightly honey scent which still lingers languidly between nose, head and heart…

by Paola Cerana
06 February 2012 Teatro Naturale International n. 2 Year 4

Tuesday, January 3, 2012

A map of world alcohol consumption

Global alcohol consumption

Drinking habits

Feb 14th 2011, 13:01 by The Economist online
A map of world alcohol consumption
THE world drank the equivalent of 6.1 litres of pure alcohol per person in 2005, according to areportfrom the World Health Organisation published on February 11th. The biggest boozers are mostly found in Europe and in the former Soviet states. Moldovans are the most bibulous, getting through 18.2 litres each, nearly 2 litres more than the Czechs in second place. Over 10 litres of a Moldovan's annual intake is reckoned to be 'unrecorded' home-brewed liquor, making it particularly harmful to health. Such moonshine accounts for almost 30% of the world's drinking. The WHO estimates that alcohol results in 2.5m deaths a year, more than AIDS or tuberculosis. In Russia and its former satellite states one in five male deaths is caused by drink.

Tuesday, December 20, 2011

Rapid oak seasoning with microbes

The Academic Wino
December 20, 2011

As a result of the relatively high cost of oak barrels, winemakers have been searching for a comparable alternative at a fraction of the cost.  Oak chips, while somewhat taboo in their earlier days, are gaining favor among winemakers as being a good alternative to the traditional oak barrel.  In blind taste tests, consumers showed no preference for wine aged in oak barrels versus wine aged with oak chips.  For the details of that particular study, click here to read a past review by The Academic Wino.
Producing staves for barrel or oak chips is not a fast process.  One of the lengthiest steps is the outdoor seasoning process, which takes anywhere from 24 to 36 months.  It is during this time that the wood undergoes many biochemical transformations of biopolymers and other compounds by fungi and bacteria.  Studies have found the fungi population present during this seasoning process consists ofAureobasidium pullulans (83%), Trichoderma harzianum, andTrichoderma konigii (the latter two making up 15% of the population).  These fungi function to hydrolyze wood heterosides (including ellagitannins, coumarins, and polysaccharides) which result in a decrease in bitterness and astringency.

Over the 24-36 month seasoning time, the fungal community changes.  Over this time, fungi belonging to the genera PenicillumGeomyces, and Geotrichum, with the species Penicillum purpurogenum the most represented.  In the internal layers of the staves, studies have found that the species Candida sp., Paecilomyces variotii, andPhialemonium sp. were the most represented molds.

Some scientists have hypothesized that by inoculating oak staves with certain fungi, they may be able to better control the metabolic reactions and therefore which wood compounds are hydrolyzed.  This could potentially lead to new seasoning places and greater customization of the desired flavors in the wine that is aged in a particular barrel or with particular oak chips.  Some studies have reported that by inoculating oak staves with fungi have increased the seasoning rate, thereby dropping the wait time for a finished staves or oak chips from 12-36 months to just one month.

The goal of the paper reviewed today, which was published last year, was to treat oak chips with certain combinations of fungi in order to potentially improve the impact of oak chips in red wine maceration, and to obtain effects comparable to wine aged in oak barrels.


The following fungi were used in this experiment:  Ph. chrysosporium Burds. (MUT 2660), P. purpurogenum Stoll (MUT 3316), A. pullulans (de Bary) G. Arnaud (MUT 3237), and Phi. obovatum W. Gams & McGinnis (MUT 2702).  The fungi used were all non-mycotoxinogenic.  After an incubation period, an agar plug (8mm in diameter from along the edge of an actively growing colony) of each fungus was used to prepare and inoculate the oak chips.  Each preparation used a different combination of fungi and growth medium.

Oak chips were toasted at a low degree and were of medium size.  A 3mL aliquot of fungi and growth medium preparations was added to a flask containing 4g of oak chips and either 12mL of laboratory medium or 12mL of saline solution.  Oak chips were sterilized either with the laboratory medium or the saline solution.

These cultures were incubated for 12 weeks in the dark under static conditions at temperatures optimized for each type of fungus.  In addition to each fungus by itself, a combination of A. pullulans and Ph. chrysosporium was studied.  For this combination, oak chips were first inoculated with A. pullulans for 6 weeks, then sterilized, then inoculated with Ph. chrysosporium for another 6 weeks.

Following the incubation period, oak chips were removed and brushed off to remove visible pieces of debris.  The chips were then used for aging of red wine using traditional winemaking processes.  The two grape varieties used were Montepulciano d’Abruzzo (70%) and Merlot (30%) from the 2006 vintage and originating from vineyards in San Severo, Apuila (southern Italy).  Artificial aging was done by placing 1g of oak chips in 500mL bottles containing the wine and storing them in a 20oC room (82% relatively humidity) for 17 days.

The following volatiles were measured and analyzed: furfural, furfuryl alcohol, guaiacol, syringol, cis-β-methyl-γ-octalactone, 2-phenylethanol, 4-vinylguaiacol, benzyl alcohol, 2,3-butanediol, γ-butyrolactone, benzylaldehyde, and 4-ethylguaiacol.  Gallic acid and ellagic acid were also analyzed.

Sensory Notes: 
  •        Furfural, furfuryl alcohol, guaiacol, syringol, cis-β-methyl-γ-octalactone are frequently present in wine after oak aging. 
  •       2-phenylethanol and 4-vinylguaiacol are known fermentation products, and have been shown to increase after oak aging.  
  •       4-ethylguaiacol is associated with Brettanomyces or Dekkera infections, and is associated with characteristic flavors such as “bacon” or “smoked”.  
  •       Cis-β-methyl-γ-octalactone is associated with oaky characteristics such as coconut and vanilla.
  •       Furfural contributes to characters such as “dried fruits” and “burned almonds”.  Studies have shown it does not play an important role in the aroma of wine, though it may strengthen the aroma of lactones.
  •       Guaiacol contributes to “burnt” overtones in wine aroma.
  •       Syringol is an indicator of the relative toast of the oak wood.  Compared to guaiacol, it has a weak odor and relatively little impact on the flavor of the wine.
  •       Benyzlaldehyde is associated with a “bitter almond” aroma.
  •       2,3-butanediol is odorless, though still contributes to the sweet taste of a wine.


  •       Cis-β-methyl-γ-octalactone was present in all wine samples.
  •       The presence and concentrations of specific volatile compounds and phenols were influenced by the type of fungus and medium used for the particular oak chip treatment.


  •       Concentrations of furfural were significantly affected by Ph. chrysosporium and P. purpurogenum by increasing in both laboratory medium and saline solution treatment.  Perception threshold was not reached.
  •       There were no significant changes with any other treatment.
  •       Furfural appears to be the most susceptible oak wood volatile compound to microbial transformations.


  •       Fungal treatment of the oak chips resulted in a significant increase in the concentration of guaiacol.

o   For the saline solution, this increase was found in the treatments inoculated with P. purpurogenumA. pullulans, and Phi. obovatum.
o   For the laboratory medium, this increase was found in the treatments inoculated with P. purpurogenum and A. pullulans.
o   For treatments with A. pullulans, guaiacol was above the perception threshold.


  •       For the saline solution, there was an increase of syringol concentrations with the treatments inoculated with P. purpurogenum.
  •       For the laboratory medium, higher levels (above perception threshold) of syringol were found in the treatments inoculated with P. purpurogenum and A. pullulans.


  •       For the saline solution, fungal treatment decreased the concentrations of benzylaldehyde (except the treatment with Ph. chrysosporium).
  •        For the laboratory medium, there was a significant increase in benzylaldehyde concentrations.


  •       For both the saline solution and laboratory medium, there was a decrease in 2,3-butanediol levels in all fungal treatments except samples treated with A. pullulans.

Ellagic and Gallic Acids

  •       Ellagic acid and gallic acid were metabolized by the fungi, with the exception of wines treated with P. purpurogenum in the laboratory medium.

What do these results means?

The results of this study show that the fungal treatment of the oak chips significantly affected the chemical profile of the wine.  Based on principle components statistical analysis, the results showed two distinct groups that affected wines in specific ways.  Oak chips treated with Phi. obovatum, A. pullulans, and the combination of A. pullulans and Ph. chrysosporium (“Group A”)affected the chemical profile of wines in one particular way, and oak chips treated with P. purpurogenum and Ph. chrysosporiumaffected the chemical profile of wines in another way (“Group B”).

Group A treated wines showed increases in guaiacol and syringol concentrations, whereas Group B treated wines showed increases in furfural and benzylaldehyde concentrations.

Even though the effect of the fungi were variable depending upon what kind of medium was used for the chips (laboratory medium versus saline solution), Group B treated wines showed increases in furfural and benzylaldehyde regardless of the medium the chips were treated with.

Based on these results, the authors claim that the microfungal treatment of oak chips increases the concentrations of some volatile components in red wine during aging.  It may be possible, that with fungal treatment of oak chips for the aging of red wines, to tailor the flavors and aromas to those desired for a particular style of finished wine.  If the goal is to have a wine with greater “toasty” character, the use of fungi from Group A may be useful.  If the goal is to have a wine with more “dried fruit” or “almond” character, then a fungi of Group B may be better.

Of course, this research is in its infancy, and more work would need to be done, particularly in regard to examining the biology and enzymatic profile of the fungi, and any potential positive or negative health consequences of using it in the aging of wines.

I’d love to hear what you all think of the use of fungi in extracting more oak character from oak chips in the aging of wine.  Please feel free to leave your comments below!

Source:  Petruzzi, L., Bevilacqua, A., Ciccarone, C., Gambacorta, G., Irlante, G., Pati, S., and Sinigaglia, M. 2010. Use of microfungi in the treatment of oak chips: possible effects on wine. Journal of the Science of Food and Agriculture 90: 2617-2626.

DOI: 10.1002/jsfa.4130

Friday, December 2, 2011

Tannin Additions Myth

New Research Busts Tannin Additions Myth, Sparks Trans-Pacific Collaboration

This just in from Washington State University

December 1, 2011

New Research Busts Tannin Additions Myth, Sparks Trans-Pacific Collaboration

A pile of tannin powder. Image courtesy Wikimedia Commons.
Tannin powder. Image courtesy Wikimedia Commons.
If you’re using tannin additions in your red winemaking process, you may well be wasting your money, according to recently published research by Washington State University enologist Jim Harbertson and Australian wine and grape researcher Mark Downey, a lead researcher at Victoria’s Department of Primary Industries.
Harbertson, Downey and their colleagues analyzed commercially available tannin additives and found them to be, at best, an unnecessary expense for red wines made from Washington-grown grapes.
Many winemaking manuals recommend adding tannins, though, in the belief that the additions help bolster mouth feel and improve color in red wine. A red wine’s mouth feel is the result of a range of chemicals causing astringency and is described with a variety of words ranging from “velvety” to “drying.”
Enologist Jim Harbertson (center) with research winemaker Richard Larsen (l) and doctoral student Frederico Cassas
Enologist Jim Harbertson (center) with research winemaker Richard Larsen (l) and doctoral student Frederico Casassa. Photo: Brian Clark/WSU.
“At the recommended dosage, these additives are, at most, giving a slight tweak to astringency,” Harbertson said. “In higher doses, you get some aroma shifting and a negative impact on sensory character. It made them earthy tasting, and turned the wine brown.”
Harbertson and Downey collaborated with renowned sensory scientist Hildegarde Heymann, professor of enology at UC Davis, and her Italian post-doctoral student, Giuseppina Parpinello, to conduct sensory analyses of Merlot and Cabernet Sauvignon wines made with tannin additions. “In a collaboration with Chateau Ste. Michelle, we added commercial tannin products to both barrel-aging Merlot and to Cabernet Sauvignon after pressing the grapes,” Harbertson said. “We used a range of concentrations and a variety of commercially available additives to get a sense of what is going on when these products are added to Washington wines.”
Harbertson explained that there is a crucial difference between taste (flavor, aroma) and astringency, or mouth feel. “Mouth feel is a tactile sensation,” he said. “It’s basically the removal of the lubricating proteins that naturally occur in the mouth. Aroma and flavor, in contrast, are receptor-based and are caused by our taste buds being stimulated by the flavor and aroma molecules in wine. Astringency is thought to be a result of chemical precipitation in which tannin molecules bind the lubricating proteins in the mouth, thus taking them out of action. That’s why some wines have a drying or ’spikey’ mouth feel, as the overabundance of tannins rob the mouth of its lubricants.”
Not only did the additives have a limited or negative impact on wine quality, analysis of the products revealed them to be, at most, only 48 percent tannin. “On the low end, we found some products to contain as little as 12 percent tannin,” Harbertson said. The products contain fillers that enable the additives to go into solution more easily. Harbertson and Downey conducted the analysis of the tannin additives.
“The bottom line for Washington red winemakers is this,” Harbertson said. “We have plenty of naturally occurring tannins available in red grapes grown here. In an industry with tight margins and dealing with global competition, we are suggesting that the added extra expense of adding tannins is simply unnecessary.”
Wine and grape research Mark Downey in his lab in Victoria, Australia.
Wine and grape research Mark Downey in his lab in Victoria, Australia. Photo courtesy Mark Downey.
Downey observed that “Tannins additives are one of the many tools available to winemakers in Australia and have been used extensively by some producers without a clear understanding of their impact. Some winemakers consider their addition essential, while for others it is more of an insurance policy, but neither approach is based on science. Given that tannin additions are an added cost, understanding their impact may result in cost-savings for producers. In the current economic climate, this is of considerable interest.”
Harbertson speculated that tannin additions might control some problems faced by white wine makers, such as protein haze or Botrytis. “But this idea has not been scientifically tested,” he pointed out.
He also mentioned that certain hybrid grape varieties, once grown in Europe for their resistance to diseases and pests, don’t produce much tannin on their own, so an additive is needed. However, most hybrids aren’t grown in Europe simply because they produce wine that is too acidic for most consumers. Several hybrid varieties are still grown on the east coast of the U.S. and in Ontario, Canada, where they are popular as constituents of the ice wines enjoyed in the region.
“This study shows us what happens when you add tannins at one end of the spectrum. What we need to do is look at the other end: adding tannins to wines from low-tannin regions or fruit grown in high volumes in a warm climate. Not all of these conditions are present in Washington or Victoria (or convenient to our research programs) so it makes sense to work together,” said Downey.
Downey said that his and Harbertson’s research programs “are complementary rather than competitive. The knowledge earned from scientific research doesn’t give you a competitive advantage. Rather, it’s how growers and winemakers use that knowledge that gives you the advantage. Working together actually achieves more for our respective industries. By collaborating and sharing the load, the Washington industry gets more research outcomes for the same research dollar invested and so do we.”
Indeed, Harbertson and Downey plan to continue their collaborative research. Among other things, they will be investigating the effects of aging red wines in oak barrels. Like so much of their work, both together and individually, the role of oak and oak’s contribution of tannins, in wine quality is assumed but not well understood. This and other questions have led the scientists’ respective institutions to sign a formal agreement, allowing them to collaborate over the long term in ways that would not otherwise be possible.
–Brian Clark
The paper discussed in this article, “Impact of exogenous tannin additions on wine chemistry and wine sensory character,” will be published in the April, 2012 issue of the journal Food Chemistry. The paper was published online Oct. 1 and readers with access to a subscribing institution may access the paper by visiting