What can be learned from grape or juice aromas?
In most white and red grape varieties, a significant amount of potential aroma compounds is bound to two sugar molecules. A considerable proportion of the aroma substances are located in the skin of the berries, therefore the maceration promotes the extraction of aroma compounds. One portion of the aroma compounds found in grapes is in free volatile and odorous form, others are glycosidically bound aroma precursors. These odourless aroma precursors can be transformed during processing (e.g. crushing, fermentation or storage) into flavour-active compounds, partly explaining the difference in flavour between wine and grape juice. Juice contains only about 10% free aromas which demonstrates the limited value of tasting grapes in the vineyard to determine ripeness.Van Rensburg, P, et. al. The development of b-glucosidase producing wine yeast for the release of flavour compounds. Winetech 2001
But evaluation of grape aromas can be made. It just takes a bit of work and time. Two methods are found in VINTNER'S CORNER
Sensory Evaluation as a Maturity Index
Method 1. Maturity and vineyard management practices can influence the pool of free aroma components. Most of the aroma components are located in the skins. The following is a procedure used to evaluate red grape aroma:
1. Approximately 200 berries are lightly crushed and pressed in a hand press.
2. The skins are separated from the pulp and seeds and placed in approximately 200 ml of 10-15% ethanol adjusted to pH 3.0 with tartaric acid.
3. The skins and alcohol are placed in an airtight jar for several days. The alcohol solution is decanted and evaluated.
Smelling the solution will provide an indication of the odor and odor intensity. Red grapes should have an odor of fruit, cherries, etc. along with "notes" of pomace or tea from the tannins. If there is little varietal aroma or aroma intensity in the grape, these two features will be deficient in the resultant wine.
Method 2. In a non-alcoholic medium juice aroma evaluation must be done with care. Rapid enzymatic oxidation can occur if berries are warm or exposed to air. For example, oxidation produces aldehydes as the result of enzymatic oxidative cleavage of linoleic and linolenic acids to hexenal. These aldehydes can produce grassy aromas that mask fruit characteristics and make aroma assessment very difficult. The procedure suggested by Jordan and Croser is as follows:
1. Use a cone-in-cone juicer, a potato ricer, a hand press etc. to press the chilled grape sample (<2 °C).
2. Estimate the quantity of juice that the sample will yield beforehand and add pectinolytic enzyme at the supplier's recommended level. Then add 50 mg/L ascorbic acid and 30mg/L sulfur dioxide. Ascorbic acid or vitamin C is an antioxidizing agent which along with sulfur dioxide will help minimize degradation of aroma components.
3. If possible, lightly sparge the juice sample with nitrogen and sieve into sample bottles which have been CO2 filled, seal and cold settle at 2 °C or less.
4. Decant the clear juice into CO2 filled bottles and carry out both chemical analysis and aroma/flavor evaluations. Note that the sample preparation method, pressing, degree of pressing vs. crushing and cold settling affects the titratable acidity and pH. Under optimum conditions, juices prepared using this methodology and stored at 0 °C will remain viable for aroma/ flavor assessment for several months.Zoecklein, B.W., K.C. Fugelsang, B.H. Gump, and F.S. Nury. Wine Analysis and Production. 621pp. Chapman and Hall, New York (1995).
Vol.16, No. 1 January - February, 2001
Bruce W. Zoecklein
Bruce W. Zoecklein
In July 2004, the following article was published.
Pretenders at the Table
Are table wines no longer food friendly?
It is well known that in the last 20 years a new style of California winemaking has overwhelmed the industry--a style of producing big, intense "trophy" wines. In attaining this new goal, wines also end up with higher alcohols. Albeit very successful at wine tastings, they are not well suited for the dinner table and, as such, should not be called "table wines." The consumer would be better served if these wines were called "social wines."
By George Vierra
By George Vierra
Traditionally, still wines have been classified into three groups, each describing when a wine is served with a meal. Wines served as cocktails or as appetizers before meals are sometimes referred to as "refreshment wines." These wines are normally dry. Their role is to stimulate the appetite or help create a festive atmosphere. Typical of these wines are Sherry, Vermouth and Madeira. "Dessert wines" are sweet, full-bodied wines appropriately served after the entrée with desserts, or perhaps alone as an enhancement to a reflective mood of a quiet evening. The better-known dessert wines are Port and the late harvest wines of Sauternes, Germany and California. The great majority of the world's wines are in the third group known as "table wines." These are to be taken with the main part of a meal, and the characteristics of this large and varied group of wines are geared to the foods they accompany.
Table wines are distinguished from one another by the grape variety or varieties used in their production and by the more subtle characteristics of the style in which they are made. Just as the artist has the option to paint a landscape in a realistic, impressionistic, abstract or other style, the winemaker has a wide choice of stylistic options. Style determines which of the many attributes of any grape variety are to be realized in the final wine. This matter of style is all-important: It ultimately determines the choice of vineyards and harvest dates, adjustments to weather conditions and crop quality, methods of handling grapes and juice, fixing of temperatures and rates of fermentation, choice of cooperage and aging strategies.
The table wine group includes a vast array of wine styles. To describe the style of winemaking that best fits the "table wine" definition, I use the term "complementary style." The overriding criterion in all winemaking decisions is that the finished wine be complementary to food.
"...the point to keep in mind in learning about which wine to serve with which dish is that the wine should complement the food and the food should accentuate and blend with the qualities of the wine. A robust wine overpowers the taste of a delicate dish..."
Mastering the Art of French Cooking,
Julia Child, et. al. 1961
In designing this style, particular attention must be paid to the physiology of the eating and tasting processes so that wines can be produced that integrate gracefully with dining. In general, these wines play down characteristics such as excessive alcohol and oakiness which lead to sensory fatigue when wine is taken with a meal. Complementary wines seek to clean and refresh the palate so that the entire meal can be enjoyed without an accumulation of strong and competing flavors. In this way, wines can bring out their natural ability to complement the best of foods and compensate for the poorer.
To achieve complementary wines, the primary emphasis is on wine balance. In order for a wine to be technically sound and enjoyable, the three components of acid, body and alcohol must be in proper proportion. That is, each component must be balanced so that it is not too weak nor too strong in relation to the other two. In practice, what actually constitutes "balance" is a subjective interpretation and as such a major source of variety in winemaking styles.
For most California wines, the body and alcohol content are deemed more important in balance considerations than acid content. The resulting wines are rich and full. Most European wines, as well as many from down under, are balanced with the acid content as a dominating partner. The resulting wines tend to be elegant rather than full. I strongly feel that acid is the most important part of the wine balance; in fact, it is the backbone upon which all else is built. In my experience, if the acid content is high and evenly distributed, alcohol and body can be correspondingly greater without upsetting the balance. Acid balanced wines are necessary to the complementary style because it is the acid in wine that cleans the palate. High alcohol generally creates a dominating and tiring effect on the palate which shows up after a few sips.
"A table wine is suitable for accompanying and enhancing the flavour of meal. Generally it is not too strong in flavour or aroma, with alcohol content of 10-12 percent. It is usually dry, or slightly sweet and lighter in body than a social wine."
F.W. Beech, wine scholar
When the alcohol content of wine sold as table wine is increased beyond the traditional limit of 14 percent, the resulting wine loses its ability to complement food. It must be acknowledged that it is possible to find wines over 14 percent alcohol that can be complimentary with some foods, but those are rare discoveries.
Since the marketability of wine can be greatly affected by ratings in wine review periodicals and services, it is understandable that this high alcohol style of winemaking has become dominant in California. But the resulting beverage should be called "social wines" to distinguish them from traditional table wines.
Everybody knows the style of wines being produced in California has changed drastically in the past 30 years. In the Napa Valley, in 1971, the grapes were picked at an average of 20.5º Brix. In 2001, the grapes were picked at a Napa Valley average of 24.2º Brix. A good rule of thumb is to use a 61 percent conversion to get alcohol levels (by volume) from sugar level (Brix). Average alcohols rose from 12.5 percent to 14.8 percent in 30 years (see Table 1 and Figures 1 & 2). In the wines, the acid fell and the pH climbed. But, the Robert Parker/Wine Spectator (RP/WS) ratings climbed. Generally, Napa Valley wines can now be considered as social wines. By all the definitions of table wines that I've found, these wines are surely pretenders and can no longer find a place at the dinner table.
Why has this social wine style become so dominant in American wineries? Winemakers say that to achieve maximum flavor profiles in Cabernet Sauvignon, for example, the grapes must be picked between 25º and 26º Brix. They're waiting for the grapes to achieve "physiological ripeness." Winemakers say they must face the fact that the market is being driven by the big, inky, black, alcoholic trophy Cabernet Sauvignons that receive 96 or 97 points. If the winemakers could make beautiful, complex, dense wines with lower alcohol, they would.2
This spiraling of the social wine style seems to be totally market driven. The following scenario probably has taken place. If Onctueux Cellars Cabernet Sauvignon gets a 97 from RP/WS, the competitors at Bourgeois Winery get a sample and bring it to their winemaker. It is tasted and analyzed. The Bourgeois winemaker is asked how to make that same style of wine. From the analysis of the Onctueux wine it can be seen that to match that style, as a starter, the Bourgeoisie must pick their grapes at 2º to 3º Brix higher than last year's harvest. And in two or so years, Bourgeois Winery hopes its Cabernet gets a 97 from RP/WS. Many other Bourgeois-like wineries follow the same tack, and the spiral continues.
This market-driven phenomenon is happening all over. Well-known wine columnist Dan Berger writes that this trend has also affected Bordeaux, according to one of his friends who owns a prestigious German winery and who once collected Bordeaux. The German vintner visited Bordeaux recently and told Berger, "Every major house has a concentrator for taking the water out of their wine. They are all making very heavy wines--wines like we never saw 25 years ago. Today, it's not Bordeaux any more." As a consequence, he said he is not buying as much Bordeaux as he once did.4
For decades California wines have been higher in fruit and alcohol and lower in acid than European wines. The difference is even greater today. Before starting Vichon Winery in 1980, over a period of several months I had about six wine tasting lunches in my home. Sitting around our dining room table, six people would taste eight different wines. Equal numbers of French and California wines were put in each tasting. We tasted Sauvignon Blanc, Chardonnay and Cabernet Sauvignon. The wines were tasted blind, scored and rated. In five out of six tastings, a California wine won.
Then we were served a meal I had planned with the caterer to accompany the wines we had just tasted. We had our meal and continued our meeting and it was noticed that the wines that came in first at the tasting were not the favorite wine with the meal. A wine that came in, say fourth at the blind tasting, was preferred with the food. It was after the meal, and only then, that the wines were unmasked. Always, the wines with higher acid, less oak and less alcohol were first to be finished with the meal--and they were always French wines. The intent of these tastings and meals was to convince my partners and marketers of the style of wines I wanted to make and the marketing message and concept to use.
What are today's winemakers' thoughts and philosophies? Professor James Kennedy wrote, "In my conversations with winemakers, they have discussed several factors that dictate ripeness.... Flavor and body development are two critical factors that are often mentioned as being important, and which develop later in fruit ripening."1
To get the fruit ripening and grape sugars higher, the winemakers employ "hang time." Hang time is a term used generally by American winemakers. Hang time is said to be important so the grape sugar levels finally attain "ripeness." Until then, it is felt the flavors in the grapes are too low or not even there. It is known, physiologically, that after around 22º Brix, berries will begin to lose weight, increase sugar and lose acid. Most other compounds will therefore, be concentrated. But alas, the berries will finally have the "ripe fruit flavor and body." It must be remembered that many of these flavors are present as precursors, so they cannot be tasted until after the wine is made and, in some cases, aged.3
"This term commonly refers to red, white or pink wines that are naturally fermented; that contain, for the most part, 10 to 14 percent alcohol; and that are consumed primarily with meals."
Defining "Table Wine" in The New Frank Schoonmaker Encyclopedia of Wine. Revised by Alex Bespaloff 1988
So, what do winemakers and wine drinkers mean by ripe fruit flavor and body? I ran a little experiment to try to get a better understanding. As a control sample, I made a lab blend of coastal red wines. The wine was composed of several different vineyards, varieties and vintages. The wine was 13.1 percent alcohol, very fruity, medium bodied and with a nice balanced acid finish. I took some Golden State Vintners Neutral Spirit Fruit Grape High Proof, at 191.2 proof, and on some sample bottles, raised the alcohol on the control to 13.6 percent. I put codes on the control and fortified wine bottles. I then took the wines to a bunch of Napa Valley winemaker friends and associates and let them taste the wines blind. (Everybody I used has been in the wine industry for many years.)
I also gave some of the wines to Daniel Dawson, owner of Back Room Wines in downtown Napa,12 and asked him to pour the wines in two coded glasses for his customers to rate in order of increasing fruit flavor and body. Daniel was told about the test but not my code. Some tasters would be asked which sample had "more fruit flavor" and others "more body"; nobody was asked to judge both. All tasters were to be given two newly coded glasses; one with the control and the other with the high-proof addition. Daniel is a merchant of fine wines, both domestic and imported, and the people who come to his shop are very familiar with the world's fine wines.
Two weeks later, upon completion of the tastings, we decoded our samples and I proceeded to put all the results together. In judging for "more fruit flavor," with 87 people tasting the two wines, 77 percent felt that the wine sample fortified to 13.6 percent alcohol had more fruit flavor than the non-fortified sample. In judging for "more body," with 101 people tasting the two wines, 94 percent felt that the wine sample fortified to 13.6 percent alcohol had more body than the non-fortified sample. So, the only thing that was changed on the control was the addition of alcohol. Yet these groups of wine people judged the high-proof fortified wines had "more fruit flavor" and "more body" when ranked with the control; the higher the alcohol, the more fruit flavor and more body. Now, this was only one experiment, and the tasting did not take place in an organoleptic lab, and I did not apply rigorous statistical analysis, but an understanding becomes clearer.
"Experience has shown that wines and foods have natural affinities for each other, and are found at their best in combination."
A Guide to Good Wine.
Allan Sichel, et. al. 1952
Now, how can winemakers get more "real" flavor in their wines? It's known that the grape's skin contains aroma compounds that are specific for certain varieties. These compounds are present as free volatile compounds that can be tasted in the berry and as sugar-bound, non-odoriferous compounds, which are considered "aroma precursors." These precursors are transformed into free volatile compounds during winemaking and aging. Also, some precursors are never transformed.8 It has been shown by many studies that the aroma precursors are at much greater levels than the free volatile compounds in grapes.5 6 7 P. van Rensburg found that juice contains only about 10 percent free aromas. This demonstrates the limited value of tasting grapes in the vineyard to determine ripeness.7
So, tasting berries for flavor seems to be of little importance. Finding ways of maximizing the production of free volatile compounds and aroma precursors in the grapes and measuring those values should be more important. To maximize flavors, the vineyard practices and correct varieties must be chosen. Once the precursor compounds are created, methods must be found to transform them during crushing, pressing, fermentation and aging into flavor-active compounds.
Since a considerable proportion of the aroma substances is located in the skin of the berries, maceration, or skin contact, promotes the extraction of aroma compounds. In one study of Sauvignon Blanc, these precursors (volatile thiols) are responsible for the grapefruit and passion fruit aromas in the wines. During skin contact, the quantity of this precursor continues to increase for 19 hours. Plus, the concentration was 200 percent greater after 18 hours of skin contact temperature of 64º F than at 50º F. 8 Eighteen hours of skin contact at 64º F may take a CO2 purging to help prevent onset of fermentation.
Now, this study was done on Sauvignon Blanc. In this variety, yeast action is necessary to release the bound aromas. These results would especially be applicable to other varieties containing S-cysteine conjugates; Pinot Gris, Riesling and Gewürztraminer.8
If it has been shown that more flavors can be put in the juice with skin contact, why do so many winemakers still swear by direct-to-press white wine making? Coarseness and astringency can be removed. Lost flavor cannot be added.
"A table wine is any wine that is not fortified or sparkling...a wine that contains a minimum of 7 percent alcohol and a maximum of 14 percent."
Linda Stradley What's Cooking America
If the winery wants to do their winemaking for the table and not the high-number ratings, how do they proceed? Aren't RP/WS 97s needed? Again, when we started Vichon, one of our wines was called Chevrier Blanc. It was made of equal parts Semillon and Sauvignon Blanc. A large part of the grapes came from Oakville and Carneros. The grapes were both picked between 21º and 21.5º Brix and the wines were about 12 percent alcohol. It was a wine with a fanciful name, lower alcohol and higher acid than the existing wines on the market. It also retailed for $10 per bottle, which for 1980, was a high price for a Sauvignon Blanc-style wine.
Our selling method was simple. We would ask our distributor representative to set up lunch reservations at a coveted restaurant account. The rep would tell the restaurant manager that we were a new winery. We would go to lunch and order the best selling, most popular Sauvignon Blanc on the market: Robert Mondavi Fumé Blanc. During lunch, we would talk with the restaurant manager and ask if he'd like to taste our wine. When he had time, he came over with two wine glasses. We poured a glass each of the Chevrier Blanc and the Fumé Blanc. We were trying to point out style difference, not quality. The Fumé Blanc was, no question, a super wine. We never failed making placement on the restaurant wine list or in their by-the-glass program. It should also be mentioned that when a new distributor was selected, a similar tasting with food was done with the distributor sales staff at their office. A few selected foods were used. We always compared Chevrier Blanc and the leader, Fumé Blanc. This was done with all distributors before the reps hit the market.
Table Wine or Social Wine?
Wine lists and retail shelves have separate sections for dessert, sparkling and table wines. Since a large proportion of table wines have more than 14% alcohol, it would be helpful to the consumer to create a new category for "social" wines. To make sure a wine will be fine for a meal in a restaurant or at home, I always have to read the label or ask what the alcohol content is before buying. When a critic reviews a wine, the wine should be defined as either a "table" or a "social" wine. State and county fairs, and other wine shows, should give separate medals for all wine categories. Social wines already pay a higher excise tax than table wines. Wineries can continue to make the wines of their choosing and label them as dessert, sparkling, table or social wines.
How successful were we? It was reported at that time: "Robert Mondavi invented Fumé Blanc in California, everyone knows that, by producing a dry wine from Sauvignon Blanc in the style of a Pouilly-Fumé at a time when most California Sauvignon Blancs were off-dry (like most California Chenin Blancs). It became a huge success, and was the number one selling wine in American restaurants for a time. Meanwhile, George Vierra started Vichon Winery and invented Chevrier Blanc (later "Chevrignon"), a dry white blend of Sauvignon Blanc and Semillon, a la a white Graves. It soared in popularity, and…it replaced Mondavi's Fumé Blanc as the #1 selling wine in US restaurants!"9
"Table wine is a dry or barely off-dry wine--white, pink or red--of 11 percent to 14 percent alcohol and meant to accompany the savory part of a meal."
I remember that in the mid-1970s, I drank and enjoyed some 15- and 20-year-old Napa reds that were in the high 11 percent and low 12 percent alcohol ranges. They had good life and nice balance. Also, if you remember, in 1976, at a Paris tasting, two Napa Valley wines--the 1972 Stag's Leap Wine Cellars Cabernet Sauvignon and the 1973 Chateau Montelena Winery Chardonnay--were considered by a group of French wine experts to be better wines than the best wines of Bordeaux and Burgundy. The analysis of the Stag's Leap Cabernet was 13.0 percent alcohol, 0.62 total acid and 3.55 pH. Those grapes were picked at 23.6° Brix, .62 TA and 3.40 pH.
There are still very nice wines being made in France with classic table wine credentials. Recently, Aubert de Villaine, proprietor of the Domaine de la Romanee-Conti in Burgundy, visited the Napa Valley to show his newly released 2001 Montrachet. This wine is listed at $1,170 per bottle. Those who tasted it felt it was under priced. The wine is 13.0 percent alcohol.10 Also, the winemakers at Louis Latour in Aloxe-Corton in the Côte de Beaune in Burgundy emailed a note stating that for Grand Cru Pinot Chardonnay and Pinot Noir they hope to harvest at 22° Brix of sugar, with pH between 3.0 and 3.2 and total acidity 7.6 to 8.4 g/L as Tartaric acid.11 Some very nice wines can be made with 22° Brix grapes.
"Table wine is grape wine having an alcoholic content not in excess of 14 percent by volume."
Code of Federal Regulations,
Title 27, §4.21. 1994.
Another example of a good table wine can be found in Australia. The Tyrrell's Vineyards, Moore's Creek, Hunter Valley/Western Australia, 2002 Semillon Sauvignon Blanc. It's 93 percent Semillon. Lovely grassy, lemony, citrusy aromas. Loads of flavor. Light-medium, body. Clean finish. Nothing better with chicken or fish. It has 10.5 percent alcohol. Their winemaker emailed me that the wine is pH 3.01 and 6.78 g/L total acidity and that they picked 18.9º Brix. I'm not aware of anything like this made in California.
Now, I'm sure almost every winemaker will say their own wines are balanced and great with food. Remember, for years, they taste their wines everyday, so they should know. When I was growing up, a couple of my uncles in Santa Clara always made wine in their basements. We'd occasionally go to uncle Sylvester's house for family dinners on Sundays. Every year they would make the wine with a combination of different red grapes. When the wine went dry, they would add a little homemade brandy to fortify it. That preserved the wine, they said. Come June or July, they'd take a siphon hose and fill a few bottles and we'd have the wines with dinner. We kids always were offered watered wine. Sylvester took wine from his barrel daily, and after removing wine for the day's dinner, he'd put the bung back in the barrel. Once a week, he'd burn a small amount of sulfur in the head space. In summer the wine was good. Later in the year, I didn't like it. I didn't understand how my relatives could drink that wine. Even the watered wine tasted like vinegar and smelled like paint thinner to me. My dad told me that it was "turning." Sylvester drank the wine every day. To him, the wine today was just like it was yesterday.
Sometime in the 1970s or 1980s, a California winery (I think it was Italian Swiss Colony) had a TV ad that I remember. A father and son were among the rows in a vineyard testing the grapes to decide when to pick. The son, an obvious university trained viticulturist, took a berry, squeezed its juice on his refractometer and after staring through the barrel said, "We'll pick in eight days." Then, a few vines away, the father, who surely had never been to the university, picked a berry, put it in his mouth and said, "We'll pick in eight days."
"...where there is a glass of wine, a plate of food cannot be very far away."
The World Atlas of Wine.
Hugh Johnson and Jancis Robinson, 2001.
The statement was the blending of Old and New World methods to make the great wines of this winery. Anybody who has ever field tested to decide if grapes should be picked, must have thought, "Oh, brother." Being able to predict heat, rain and wind, not even to speak of silly things like tank space and picking crews, was not part of the equation. It was a nice warm feel-good ad, but with very little of the real world or science. I wonder if we will soon see TV ads showing a winemaker among the rows in a vineyard tasting the grapes to look for flavor and body and deciding when to pick? wbm
1 Dr. James Kennedy, Dept. of Food Science and Technology, Oregon State University (personal communication), May 2002.
2 Heald, Elanor and Ray Heald, "Cabernet Sauvignon Cultivates a Foothold," Practical Winery & Vineyard, Jan/Feb 2004, pg 46-54.
3 Dr. Richard Smart, "Hang the Hang Time," Practical Winery & Vineyard, January/February 2003, pgs. 5-6.
4 Dan Berger's Vintage Experiences Volume VIII, Issue 35 October 23, 2003 "Portified Cabernet."
5 Y.Z. Gunata, "Recherches sur la fraction liée de nature glycosidique de l'arôme de raison: importance des terpénylglycosides, action des glycosidases. Doctoral Thesis, Montpellier, 1984.
6 Williams, P.J., et. al., "Classification of monoterpenoid composition of Muscat grapes," Am. J. Enol. Vitic. 32:250-255, 1981.
7 P. van Rensburg,et. al., "The development of b-glucosidase producing wine yeast for the release of flavour compounds." Winetech, 2001.
8 Catherine Peyrot des Gachons, "Aroma Potential of Sauvignon Blanc Grapes (Vitis vinifera L. cv Sauvignon blanc)," Doctoral Dissertation, Oenology Department, Victor Ségalen University, Bordeaux, 2002
9 John E Murphy email@example.com
10 Dan Berger, Napa Valley Register, January 13, 2004.
11 Personal communication, February 2004.
12 Daniel Dawson, owner, Back Room Wines, 974 Franklin St., Napa, CA 94559 toll free 877.322.2576, http://www.backroomwines.com/.