Thursday, February 28, 2013

Oscars, Mole and Wine

We had some friends over for Oscar evening. We decided to make wild turkey with mole sauce, chile rellanos and plantain rice. Let me digress for a moment. Making mole sauce is not a trivial thing, the last time we made it, it delayed our dinner by 3 hours so this time we were prepared and made the sauce the day before, but it did take the better part of the day, not to mention getting all the ingredients.
What better wine to pair this dinner with than with something from Spain. We'd been saving this 1991 Viña Tondonia Gran Reserva wine for a special occasion. We have had the Viña Tondonia and Viña Bosconia Reserva and have totally loved the wines but this was our first taste of the Gran Reserva. It did not disappoint and went so well with the dinner. For a wine that is now approaching it's 25th year, it was still bright, with red cherry and spices. Our friends brought another wine from Spain that evening and it is so unsual and special that I am saving it for it's own blogpost, so stay tuned.

Tuesday, February 26, 2013

A Wine Tour of France By Frederick S. Wildman, Jr.

I recently read the 1972 edition of Frederick S. Wildman, Jr.'s A Wine Tour of France. In one of the first chapters in the book, Wildman provides an overview of the 21 day itinerary beginning in Paris and going clockwise through the wine regions of France. Each region begins with a map of the area and Wildman provides you with information about the best vineyards, hotels to stay at, and places to eat. Since the information is now 40+ years old, I wonder how many of these places still exist?
No matter, the most enjoyable part of the book is the history that is peppered throughout the narrative, which provided me with a better appreciation of the many famous wine regions. For example, on his trip to Burgundy, he stopped off in Gevery-Chambertin (pg. 83). Although the vineyards were probably planted during Roman times, the first mention of vines in Chambertin can be traced to 630 A.D., when the Burgundian Duke Amalgaire bequeath a vineyard to the Abbey of Bèze, which later became Clos de Bèze. There is a legend that surfaces around the 12th century of a peasant named Bertin who had a field adjacent to the Benedictines' Clos de Bèze. Taking a cue from his Benedictine neighbors, Bertin decided to plant his field to grapevines. The wine that he made from these grapes was "marvelous" and the "field of Bertin" or champ de bertin is what we now know as Chambertin. Chambertin was reputedly Napoleon's favorite wine. Stories like this is why I found the book to be such a wonderful read.

Sunday, February 24, 2013

Wines & Vines---Eucalyptus Aromas: A Mystery

I came across the article "Eucalyptus Aromas: A Mystery", in the February 2013 issue of Wines & Vines1. It captured my interest because I read that Robert Mondavi's To Kalon Vineyards abuts a grove of eucalyptus trees and wines made from grapes that are closest to the eucalyptus often tastes of eucalyptus. In this article, the researchers from the Australian Wine Research Institute conducted various experiments to determine where the eucalyptus aroma and flavor came from.
The flavor comes from a chemical produced by the eucalyptus trees called, eucalyptol. Eucalyptol, also called 1,8-cineole is a monoterpenoid cyclic ether.2
Consumer studies showed that there was a preference for wines that were spiked with either 4 micrograms per liter (μg/L) or 30 μg/L of 1,8-cineole, with more consumers preferring the higher concentration. When 1,8-cineole was found in a wine, organoleptic descriptors such as "eucalypt", "camphor", "fresh", and "minty" were evoked. The researchers found that wines made from grapes growing closest to the eucalyptus grove contained more 1,8-cineole, but the 1,8-cineole came from the inclusion of eucalyptus leaves that was present in the machine harvested grapes and not from the eucalyptus oils on the grapes. From a series of experiments, it was determined that an addition of 4 eucalyptus leaves and a small piece of bark totalling 3.6 grams in 50 kg of hand harvested grapes resulted in a dramatic increase in the concentration of 1,8-cineole in the wine (30 μg/L).
If you find that you are tasting flavors of eucalyptus, camphor or mint, you might consider looking into the location of the vineyard from where the wine was made. I found this to be fascinating!
References:
1. Dimitra L. Capone, I. Leigh Francis, Markus J. Herderich and Daniel L. Johnson, Eucalyptus Aromas: A Mystery, Wines & Vines, February 2013, pg. 52-57.
2. Wikipedia entry for Eucalyptol.
All structures were drawn by the freely available drawing program from ACD Labs called ACD/ChemSketch Freeware.

Friday, February 22, 2013

Vineyard Planting Schematic

Bill, Jeff, Barry and my husband worked on our north field during the fall and winter of 2012. There was a lot of work to do. It began with turning the north field and removing all of the boulders located in the topsoil. At the same time, we sent away our soil samples to be tested for the pH and nutrient content. After we received the report, we contracted Fieldworks and Crop Protection Services to amend our soils. Time was running out where it would be possible to work the land, but Mother Nature was kind and allowed the extensive work of tiling the field to occur, albeit in snowy, cold and windy conditions.
Our north field, now has dimensions of 826 feet north to south and 295 feet east to west. These exact dimensions allowed us to further define the plantable area of our vineyard. Since we are planting using a 4 feet in row vine spacing and a 7 feet between row spacing, we know that we need 1556 vines for an acre. We left a north headland of 35 feet to allow for turnaround space for our equipment and left 25 feet on either side of the east-west borders of the vineyard. This meant that we had a total of 756 feet for the north-south dimension and 245 feet for the east-west dimension. What this translates into is that for our 4x7 feet planting, we will have 189 vines north-south and 36 rows, east-west.
Originally, we ordered a specific amount of vines to cover this area, but now with the exact dimensions of the vineyard having been determined, we knew exactly how many vines we needed to cover the total area. Fortunately for us, when we contacted Mercier Vineyards, although this was their first venture into growing tall grafts, they mentioned that they had a better than expected success rate and had additional tall grafts that we could purchase. Great news!
The typical recommended vine density spacing is 6 feet by 8 feet which will accommodate 908 vines per acre. With land being the limiting factor, our 4x7 density makes the most use of the available space. Therefore, in our current field, which is approximately 4.25 acres, we are effectively planting the equivalent of approximately 7.5 (6804/908) acres of plants.

Wednesday, February 20, 2013

2009 Chateau La Tour de Mons Margaux

I remember the Valentine's Day that we spent with our friend, he had just gotten his citizenship so it was a dual celebration, unfortunately, his wife was not feeling well, so it was just the three of us at Basil's Restaurant in Narragansett, Rhode Island. Basil's has an extensive wine list with wines from all over the world and our eyes happened upon the 2005 Chateau La Tour de Mons Margaux. We had that wine with dinner and it was wonderful. The next time we were treated to this wine was just this past Christmas, with the same friend and two other snowbirds who are currently in Florida. Again, the wine was a delicious complement to the Christmas Eve dinner. So, when my husband came across the 2009, we tried it and though it was drinkable now, it was a little youthful. The 2009 is a blend of 34% Cabernet Sauvignon, 55% Merlot, 5% Cabernet Franc, and 6% Petit Verdot. We decided to purchase a few bottles to lay away for the not too distant future enjoyment. This is a well crafted wine with a great balance of fruit and soft tannins. With the cost being less than $30.00 per bottle, this is an excellent buy!

Tuesday, February 19, 2013

Conferences in the Northeast

If you live in the Northeast, here are some upcoming conferences that may be of interest to you:
1.  Harvest New England Ag Marketing Conference and Trade Show
Making “Cents” in Today’s Marketplace

February 27 - 28, 2013
Sturbridge Host Hotel, Sturbridge, MA

2.  Eastern Winery Exposition
March 6-8, 2013
Lancaster County Convention Center
Lancaster, Pennsylvania

3.  Wineries Unlimited
March 12-14, 2013
Greater Richmond Convention Center
Richmond, Virginia

New Tab called "Grape and Wine Chemistry"

One thing about blogs is that the most recent post is what you read first, which makes sense unless the most recent post is one of a series of posts on the same topic. Recently, I posted some information on the chemistry of the grape berry and it was clear in my mind that I wanted to start from non-flavonoid chemistry and then go to flavonoid chemisty and discuss the flavan-3-ols, flavonols and then the anthocyanins. In order to make sense of this, I created a tab called Grape and Wine Chemistry so that I can keep track of the blogposts that relate to these topics.
On any of these blogposts, if there are images, you can always click on the image to see a larger version of it. There is a "x close" that will appear on the upper right hand side of the larger image which will take you back to the blog.
If there are any questions or corrections that you'd like to email be about, please feel free to do so. Thank you very much for visiting my blog.

Sunday, February 17, 2013

Where Does Hydrogen Sulfide Come From?

The good news is that Saccharomyces cerevisiae ferments sugar to alcohol and in the process produces wine. The bad news is that S. cerevisiae is the culprit that produces hydrogen sulfide (H2S), the odor of rotten eggs. While alcohol in wine is appreciated, wine smelling of rotten eggs is not. Moreover, the sensory threshold for hydrogen sulfide is on the order of 1 μg/l or 1 part per billion (1 ppb), a very small amount. Yeasts can use elemental sulfur, sulfate, sulfide, sulfite, and organic sources of sulfur in grape juice to produce hydrogen sulfide. 1
The yeasts have to produce hydrogen sulfide because this is an intermediate in the biosynthesis of sulfur containing compounds required by the yeasts for cell growth and function. The two times when yeasts can create a surfeit of hydrogen sulfide are (1) during the exponential growth phase and (2) at the end of fermentation when autolysis of yeasts can lead to hydrogen sulfide production, especially if left on the lees too long. But, it's not fair to put all the blame of hydrogen sulfide production on the yeasts. Other contributing factors include:
The above list is by no means a comprehensive one, but it is a start at untangling a multifactorial problem which can result in excessive hydrogen sulfide production.
References:
1. Bruce Zoecklin, Factors Impacting Sulfur-Like Odors in Wine and Winery Operations, 8th Annual Enology and Viticulture British Columbia Wine Grape Council Conference, July 23-24, 2007.
2. UC Davis OnLine Course, VID254 Wine Quality
3. R. S. Jackson, “Wine Science Principles and Applications”, Third Edition, 2008, Academic Press.
4. Seung K. Park, Roger B. Boulton, and Ann C. Noble, “Formation of Hydrogen Sulfide and Glutathione During Fermentation of White Grape Musts”, Am. J. Enol. Vitic., Jun 2000; 51: 91 - 97.

Friday, February 15, 2013

Unintended Bottle Bouquet the Flipside of TCA

In an earlier post, I wrote about how using cork closures, as well as using chlorinated products for sanitation can lead to a wine illness called cork taint. Well, all is not safe merely by switching over to screwcaps because screwcapped wines can be stinky in another chemical way.
George Taber wrote in his book To Cork or Not To Cork, about Alan Limmer, chemist and winemaker who had concerns about high-tannin wines like Syrah and Cabernet Sauvignon under screwcaps. Alan Limmer wrote an article for the New Zealand Winegrower entitled The Chemistry of Post-bottling Sulfides in Wine where he makes an argument that there is a difference in redox (reduction-oxidation) chemistry in wine under cork versus screwcap closures. Limmer goes on to say that wine can never be bottled free of sulfides. The more noticeable sulfides are the simple sulfides such as H2S or hydrogen sulfide which smells like rotten eggs and H3CSH or methanethiol (methylmercaptan) which smells like rotten cabbage or burnt rubber.1 Delightful! not!
Traditionally, wineries rack their wines to get rid of the simple sulfides such as hydrogen sulfide. Methanethiol, on the other hand may simply be oxidized to dimethyl disulfide which has a much higher sensory threshold. Therefore, if there are disulfides in the bottled wine, and the wine is under a sufficient reducing environment such as a screwcap, the following equilibrium can occur where the dimethyl disulfide is reduced back to methanethiol which has a much lower sensory threshold.
Once this chemical explanation of redox in bottled wine was discovered, screwcap manufacturers such as Stelvin have found a way increase oxygen permeability. Saran/tin and Saranex are used by all screwcap manufacturers, of which there are now several. Saran/tin has a metal layer, which allows very little oxygen transmission, Saranex allows a bit more in order to keep the redox environment from sifting back to a reducing environment.2
Many articles have been written on the proper selection of closures a few a provided below.
References:
1. Alan Limmer, The Chemistry of Post-bottling Sulfides in Wine, Chemistry in New Zealand, September 2005.
2. Jamie Goode, Finding Closure, Wines & Vines, August, 2008.
Additional Reading:
1. Bruce Zoecklin, Factors Impacting Sulfur-Like Odors in Wine and Winery Operations, 8th Annual Enology and Viticulture British Columbia Wine Grape Council Conference, July 23-24, 2007.

Tuesday, February 12, 2013

Champagne for Valentine's Day

Champagne is champagne only if it comes from Champagne. Otherwise, it must be called "sparkling wine" or prepend the geographic location of it's provenance such as "California champagne". However, "sparkling wine" can be made using the traditional method known as methode champenoise, where the carbon dioxide that creates the bubbles comes from a second fermentation in the bottle. If the bubbles come from artificial carbonation, the product cannot even be called "sparkling wine". Buyer beware!
There is an apocryphal story around the 1660s, that attributes the creation of champagne to a Benedictine monk named Dom Pérignon who was cellar master at the Abbey of Hautvilliers. Dom Pérignon was keenly aware that oxygen was the ruin of a good wine so he experimented with many different closures including olive oil film, rolled up grape leaves and then eventually cork. By using cork, the carbon dioxide that usually escaped through the oil film and grape leaves remained in the wine. Upon tasting this wine, Dom Pérignon remarked, "I am drinking stars!"1 The production of sparkling wine begins with a base wine, called the cuvee. This is a low alcohol wine (9-11%), with moderately high acidity (7-9 grams/Liter) that is fermented to dryness. The grapes used in making champagne are Pinot Noir, Pinot Meunier and Chardonnay. Since the grapes are picked when the oBrix is between 18-20, there is very little varietal flavor associated with the base cuvee regardless of which grape it is made from. Sparkling wines made entirely from Chardonnay are sometimes called “blanc de blances” (literally “white from whites”), while those made entirely from red grapes are sometimes called “blanc de noirs” (“white from blacks”).
A really good reference for making champagne can be found here: 2.10 Making Sparkling Wine (Methode Champenoise). Champagne bottles come in various sizes and they all have a name which I found to be very interesting. I've lifted the following photo of champagnes from that site:
  • 1. Quarter or Piccolo    187 ml
  • 2. Half-bottle                 375 ml
  • 3. Standard Bottle         750 ml
  • 4. Magnum                    1.5 liters
  • 5. Jeroboam                  3 liters
  • 6. Rehoboam                4.5 liters
  • 7. Methusaleh                6 liters
  • 8. Salmanazar               9 liters
  • 9. Balthazar                 12 liters
  • 10. Nebuchadnezzar   15 liters
Wishing you a happy, bubbly, Valentine!
Reference:
1. Frederick S. Wildman, Jr., "A Wine Tour of France", William Morrow & Company, Inc., New York, 1972, pg. 38-39.

Sunday, February 10, 2013

2010 Paumanok Assemblage Brightens Our Confinement

All in all, there is not much we can complain about. We don't think we had more than 15 inches of snow, which began falling in earnest around 4 p.m. on Friday afternoon, Feb 8. By that time, my husband had picked up our son, who timed his visit from Washington, D.C. to coincide with the blizzard of 2013. Our lights began flickering around 7:30 so we decided to turn off our computers and hunker down. We woke around midnight and much to our relief, we still had power! The next morning, we woke up to a message from Governor Malloy saying that all roads have been closed to travel. Looking out from our front window, we saw some kind of wire dangling across our street. My husband determined that it must either be a cable or phone wire and this was confirmed by our neighbor who said that it was no longer in use, so coiling the wire up, we started to shovel.
Our street had still not been plowed and we didn't know how the major roads were so we made use of our confinement by reading until it became time for dinner. Hmmm....not much to eat besides cold cuts we bought just in case we didn't have power. However, taking a page from the Iron Chef, we made nachos with blue corn tortilla chips, a mélange of cheeses and leftover chili. While I was making this concoction, my husband looked for a suiable wine and he came up with the 2010 Paumanok Assemblage. With my first sip, I thought, "Wow! luscious fruit with a backbone of soft tannins!"

On the back of the bottle: 2010 is one of our best Grand Vintages at Paumanok. This Assemblage is a blend of 35% Merlot, 33% Cabernet Sauvignon, 21% Petit Verdot and 11% Cabernet Franc. 445 cases were bottled.

Friday, February 8, 2013

Chemistry of Cork Taint

After reading George Taber's book To Cork or Not To Cork, I looked up a few references that were mentioned in the book in order to learn more about the chemistry of cork taint. As mentioned below in the book review, in 1981, Hans Tanner and his colleague Carla Zanier, used GC-MS (gas chromatography-mass spectrometry) to identify the offending compound of cork taint to be 2,4,6-trichloroanisole or TCA, which smells to many like wet cardboard having a musty or moldy off odor. The reason why TCA is so problematic is that it has a very low threshold of detection. Anyone can detect TCA at a level of 100 parts per trillion (ppt or nanogram/Liter), nine out of 10 can detect it at a level of 30 ppt, and at 10 ppt, half of the testers can detect TCA.1
There is a family of chloroanisole compounds that can lead to cork taint, but does not necessarily have to come from cork itself.
Pentachloroanisole was found in huge inventories of French wines in the 1980's. The offending material was traced to the chlorine-based pentachlorophenol, one of the compounds in wood preservatives being used in the wineries during that time.
In 2003, Hanzell Winery in Sonoma, a producer of world class Pinot Noir and Chardonnay had a problem with TCA in their wines. Rather than trying to prevent word of TCA contamination from reaching the public, Jean Arnold the winery president shared her story with the public. TCA contamination was traced to the prolonged use of chlorinated sanitation products. The TCA taint was found not only in the wines, but in the winery where chlorine was being used. Arnold's honesty, grace and leadership translated into trust and leadership in the Hanzell brand.2
The question is "How does this cork taint develop?" In the case of cork itself, the starting compound called "phenol" is found in lignin, in the cork bark. The process of disinfecting the cork bark using chlorinated bleaching compounds transforms the phenol into 2,4,6-trichorophenol (TCP), then microbial action on the TCP yields 2,4,6-trichoroanisole.3
These days, corks are no longer treated with chlorine and Winery Sanitation Workshops strongly advise against the use of any chlorinated cleaning agents for sanitizing the winery environment.
References:
1. George M. Taber, To Cork or Not To Cork, Scribner, 2007, pg. 33, Scribner, 2007, pg. 33.
2. Michael Fineman, "Brand Promise Fulfilled", Wines and Vines, February, 2013, pg. 62-64. See also, George M. Taber, To Cork or Not To Cork, pg. 181-191. 3. Carlos Macku, Ph.D. and Kyle Reed, Ph.D.,Factors Affecting Closure Selection. Practical Winery and Vineyard Journal, Winter, 2011.
Additional Information:
Dr. Alan Limmer, Cork as a Closure--Post-Bottling Reduction and Permeability Performance, Napa, June, 2006.
María Luisa Álvarez-Rodríguez,1 Laura López-Ocaña, José Miguel López-Coronado, Enrique Rodríguez, María Jesús Martínez, Germán Larriba, and Juan-José R. Coque1, Cork Taint of Wines: Role of the Filamentous Fungi Isolated from Cork in the Formation of 2,4,6-Trichloroanisole by O Methylation of 2,4,6-Trichlorophenol, Appl Environ Microbiol., 2002, December; 68(12): 5860–5869.
All structures were drawn by the freely available drawing program from ACD Labs called ACD/ChemSketch Freeware.

Wednesday, February 6, 2013

To Cork or Not To Cork by George M. Taber

When we visited Paumanok and got a chance to meet and speak with second generation winemaker, Kareem Massoud, he mentioned that a good read was the book To Cork or Not To Cork by George M. Taber. I've read another book written by George Taber called Judgement of Paris, which I really enjoyed so we bought this book to learn all about corks and other wine closures.
Why dedicate an entire book to cork? During the UC Davis online course, we had a discussion forum devoted to cork and other closures. Had I read this book, I would have been more informed on the controversy. Although cork as a closure for wine has been around since the ancient Roman era and industrial cork was made in Anguine, Spain in 1750, the controversy surrounding cork as a closure came to prominence in the 1980's with a seeming epidemic of cork tainted wines.
The French were experimenting with a screw cap closure called Stelcap-vin, later shortened to Stelvin in the 1960's. Australian winemakers were also looking for alternatives because they were experiencing major cork failures leading some to feel that they were the dumping ground for poorer quality corks.
In 1981, Hans Tanner and his colleague Carla Zanier, using GC-MS (gas chromatography-mass spectrometry) identified the offending compound of cork taint to be 2,4,6-trichloroanisole or TCA. Their work was published in the Swiss Review of Fruit and Wine written in German and English, French and Italian abstracts of the study were also published.
Not all the problems of cork taint arose from cork. During the 1980's France was faced with a problem that affected their entire inventories of wines. Pierre Chatonnet traced the problem to chlorine-based pentachlorophenol, one of the compounds in wood preservatives used around wineries. Pentachlorophenol can become pentachloroanisole, a compound similar to TCA in it's structure.
Taber also gives detailed accounts of alternative closures such as SupremeCorq and Neocork as well as technical cork products such as Altec. One chapter is about the Austrlian experiment designed to test 14 different closures using Semillon, a light, white wine.
It is a comprehensively researched, yet approachable book on cork and alternative closures. An all you wanted to know but were afraid to ask book which George Taber peppers with vignettes called Message in a Bottle, which I found to be very interesting.

Monday, February 4, 2013

Cofermentation of Syrah and Viognier

I read an interesting article in the American Journal of Enology and Viticulture entitled Cofermentation of Syrah with Viognier: Evolution of Color and Phenolics during Winemaking and Bottle Aging.1
I've heard of the practice of cofermenting Syrah with Viognier and my preconceived notion is that this practice leads to better color retention for the Syrah.
The article begins by mentioning that both Syrah and Viognier are Rhone varieties and appear to be genetic siblings. I went to consult the handy Wine Grapes2 and there it was---Syrah is the genetic offspring of Mondeuse Blanche and Dureza and one of the parents of Viognier is Mondeuse Blanche, so it looks like they are half-siblings.
In this study, 100% Syrah was used as a control and Viognier at 3 different concentrations of 5, 10, and 20% during crush was used to test the hypothesis that the wines with the varying concentrations of Viognier would show differences in phenolic concentration as well as differences in color relative to the control.
The various experiements conducted by the authors lead to the conclusion that confermentation of Syrah with Viognier did not lead to any differences in composition of the wines compared with the control. Moreover, when the Viognier concentration reached 20%, this lead to a lower concentration of anthocyanins and flavonols, suggesting dilution of these compounds, which lead to less color intensity. There goes a preconceived notion out the door!
The authors suggest that a future project might involve using pressed skins of Viognier to see if the phenolic contribution from the Viognier pressed skins would lead to better color retention and not to dilution of the anythocyanins from the Syrah and phenolics.
References:
1. Federico Casassa, Landon S. Keirsey, Maria S. Mireles, and James F. Harbertson, Cofermentation of Syrah with Viognier: Evolution of Color and Phenolics during Winemaking and Bottle Aging, Am. J. Enol. Vitic., December 2012 63:538-543.
2. J. Robinson, J. Harding and J. Vouillamoz, Wine Grapes - A complete guide to 1,368 vine varieties, including their origins and flavours, pg 1026, Allen Lane 2012 ISBN 978-1-846-14446-2.

Sunday, February 3, 2013

2007 McCall Reserve Pinot Noir

We had this 2007 McCall Pinot Noir with mushroom and prosciutto stuffed deboned breast of chicken. The color was a sparkling ruby in the glass, with flavors of red berries that went deliciously with the meal. We feel that a Pinot Noir from Long Island is truly an accomplishment. The back of the bottle mentions that September 2007 was the beginning of a beautiful Indian summer. They don't call Pinot Noir the "heart break grape" for no reason. Weather that is perfect for the early ripening Pinot Noir grape is difficult to come by in the Northeast. Our recent Septembers have been wetter than normal, most notably in 2011, when Hurricane Irene came into the area dumping huge amounts of rain, which is the nemesis of Pinot Noir. So, this bottle, which is made from 100% Estate grown and hand selected grapes reflects the McCall's vision of crafting very special wines.
Learn more about the McCall Wines here: Link to McCall Wines

Friday, February 1, 2013

Anthocyanins Give Red Wine Their Color

The third class of Flavonoids Found in Grapes are the anthocyanins. The anthocyanins exist in grapes as the glycoside, which means that the flavonoid portion, or the aglycone is complexed with a sugar.1 Red wine color comes from the anthocyanins contained in the skins of the grape unless the grape is a variety of teinturier, where even the pulp of the grape is colored. One of the reasons why Pinot Noir is not a very highly colored wine is that it contains only the five anthocyanins shown below, whereas other red varieties contain these 5 anthocyanins as well as anthocyanins that are further modified.
There are 5 basic anthocyanins as shown below:2
In the table below, the structure that is shown is a generalized anthocyanin with R groups that can be modified at R1, R2, R3, R4 or R5 to give the various forms of anthocyanins that can be present in grapes.1
The substitution pattern on the phenyl ring with R1, R2, and R3 groups affects the color that we perceive. The more hydroxyls (-OH) that are on the phenyl ring, the bluer the hue of the wine. The more methoxy (-OCH3) substituents on the phenyl ring, the redder the hue of the wine. Since the most prevalent anthocyanin in grapes is malvidin-3-glucoside, the hue of a young wine is red.
References:
1. Jackson, Ronald S., Wine Science: Principles and Applications, Third Edition, Elsevier, Academic Press, 2008, pg. 287. The anthocyanin chart also comes from Ronald Jackson, pg. 287.
2. Douglas Adams, VI257, Lesson 8, pg. 23.
All structures were drawn by the freely available drawing program from ACD Labs called ACD/ChemSketch Freeware.