Eiswein (Ice-wine): The process is very similar to passerillage, and the grapes are left on the vine to freeze inside the ice while they shrink inside, concentrating their juices and sugars to produce a sweet white wine high in alcohol. This method of making sweet wines is naturally found in colder wine making regions such as Germany, Austria, Hungary, Upstate New York and Canada.
The result of both noble rot and passerillage is a concentrated sweet wine high in sugar content and alcohol; delightfully unctuous and viscous. At their best, these wines are so volatile that no sooner do they enter the mouth than they evaporate. Rising straight to the olfactory bulb, they are immediately absorbed into the deepest recesses of the brain and fill us with a sense of ineffable joy. These late-harvest wines are most traditionally found in Tokaji wines from Hungary, Vendange Tardive wines from Alsace, and Monbazillac, Sauternes, and Barsac wines from Southwest France. The high cost of labor is reflected in the prices and a single bottle of Château d’Yquem Sauternes was recently auctioned for $115,000.
Dormancy: After all the grapes have been harvested, like a bear in winter the vine shuts down and hibernates until the coming of spring when the cycle begins anew. When the leaves have fallen and the stem shrivels and dries out, it once again resembles a piece of dead driftwood. Looking at a bare and bleak vineyard in winter, it is hard to picture the green and verdant views of the summer. For this reason the vine has always held a sacred, sometimes religious symbolism of rebirth. The Egyptian God Osiris was both the God of wine and the God of rebirth, as was the Greek God Dionysus; features of both were incorporated into Christian symbolism as we discuss in the next chapter, “History of Wine.”
Viniculture: Making the Wine (Sugar + yeast = alcohol + CO2)
The Vintner: From the moment the grapes have been harvested, an organic process of decay begins. The natural yeasts in the skin will react with the sugars in the flesh of the grape to produce alcohol and carbon dioxide. When the sugars are all consumed, or the alcohol level reaches about 14 degrees ABV (alcohol by volume), this process of fermentation ends. The next stage in this natural cycle is for the oxygen in the air to transform the alcohol into vinegar, which in turn is transformed by bacteria back into carbon dioxide and water, ready to be extracted from the air and the earth by a new generation of vines. It is the job of the vintner to control this natural cycle and to bottle the wine before the oxygen turns it into vinegar.
Pre-Fermentation: From the moment the grapes are picked four processes can occur:
White Wine: The grapes are quickly crushed, separated from the skins, and the juice is kept at a low temperature and usually protected by an inert gas so that no oxygen can start the fermentation process. Because the skins were immediately removed, the juice is a clear color and will produce white wine. The different shade of white, from pale-straw to rich-golden, depends on the variety of grape used. Before fermentation is allowed to occur, the juice is rigorously filtered until all impurities are removed.
Red Wine: After being separated from the leaves and stems, the grapes are crushed and the juice and skins are allowed to ferment together in the fermenting vat. The skins add color to the juice, resulting in red wine. The skins also contain tannins, which is why red wines are more tannic and need more aging. This mixture of juice and skin is called the must.
Rosé Wine: Prior to fermentation, the juice is exposed to the grape skins long enough to acquire some coloring.
Raisinated Wine: The grapes are left on straw mats to dry out in the sun, becoming like raisins, with a high concentration of sugar later resulting in a powerfully alcoholic wine. This is the process by which the best and most expensive wines used to be made, but these days is usually limited to the shores of the northern Italian Lake Garda where the wines are called Recioto and Amarone.
Fermentation: Fermentation is the process whereby the sugars in the grape juice interact with the yeasts in the skin to produce alcohol and carbon dioxide. As soon as the grape juice is exposed to the oxygen in the air, the naturally occurring yeasts are able to react with the sugars. The carbon dioxide bubbles through the juice and raises the skins and residue of the grape to the top of the vat, where it forms a skin called the cap. The cellar workers stand at the top of the vat and break this cap so the pieces float down in the vat to interact further with the must, which, at the same time, is exposed to more oxygen. Punching down through the cap obviously extracts more tannins and other compounds from the skins as they macerate in the juice, and the cellar master will be constantly tasting the results to know when to stop punching before the wine becomes too dark or too tannic.
Composition of Grapes / Wine
Grape
Wine
Water
75.0%
82.9%
Sugars
22.0%
0.1%
Alcohols
0.1%
14.5%
Organic Acid
0.9%
0.6%
Minerals
0.5%
0.5%
Phenols
0.3%
0.3%
Proteins
0.2%
0.1%
99.0%
99.0%
Figure 2: Transformation of sugar into wine
Although yeasts occur naturally in grapes, modern wineries often also use cultured yeasts for the additional control they bring to the process. The yeasts react with the sugars in the grape juice to produce ethyl alcohol (ethanol) and carbon dioxide, and so the higher the concentration of sugar, the higher the resulting alcohol. This is why juice low in sugar—for example from regions like Germany with less sunshine—produce wines with lower alcohol levels. The yeast continues producing alcohol until there is no sugar left. However, after a maximum alcohol level is reached (usually about 14-15 percent), the alcohol kills off the yeast. A juice with a very high sugar content (such as the late harvest wines discussed above) will thus have residual sugar remaining, even after the maximum alcohol level has been reached. That’s why these late harvest wines are celebrated for being sweet as well as powerfully alcoholic.
When the fermentation has finished and all the sugar has been converted to alcohol, the free-run juice (now wine) is run into barrels for the secondary fermentation. The remaining juice and skins in the fermentation tanks are then pressed, and the secondary or pressed-juice will have more body and color than the initial free–run wine and will be used for blending or for distillation into brandy or marc.
Chaptalization: Sugar is sometimes added to the still fermenting wine, not to make it sweeter, but to allow the yeasts to produce more alcohol. Obviously, this occurs only in regions with low sunlight, like Germany or Northern France where the lack of sunshine means the unripe grapes lack sufficient sugar to produce enough alcohol by themselves. The process is named after Napoleon’s Minister of the Interior, Jean-Antoine Chaptal, who introduced the concept as a way to improve French wine which had suffered neglect through years of revolution and war.
Secondary (Malolactic) Fermentation: Because most white wines were rigorously filtered prior to fermentation, they can be bottled and shipped as soon as the primary fermentation has been completed. Red wines, however, are subject to a secondary fermentation, called malolactic fermentation. Although it is a naturally occurring process, this secondary fermentation was not really documented until the mid-nineteenth century, when scientists such as Louis Pasteur described
the effect of bacteria on wine. It was not until the 1950s that a wine professor at the University of Bordeaux, Émile Peynaud, was able to describe the malolactic process and give winemakers the tools to harness it. Prior to Peynaud’s work, the great red wines of Bordeaux needed decades of aging before they were ready for drinking. Thanks to malolactic fermentation, these wines now mature much faster and can be drunk much sooner with no loss of quality.
Malolactic fermentation usually takes place in oak barrels and is the process by which the harsher, naturally occurring malic acids of the grapes are converted by bacteria into the softer lactic acids, and the rough edges of the tannins are rounded out. Lactic acids are actually a bacterium named Oenococcus, which eats and digests the malic acids—but there does come a point when the serious wine drinker says “enough already with the bacteria.”
This secondary fermentation is a naturally occurring process which normally takes place after the sugars have been converted to alcohol, and is encouraged by winemakers as it removes the tart, acidic taste of young wine and replaces it with a softer, more buttery taste and increased mouth-feel. Some light reds, such as Beaujolais, which are low in tannins, do not need this secondary fermentation and can be bottled (and drunk) soon after harvesting. Conversely, some white grapes, such as Chardonnay, do benefit from this secondary fermentation and some exposure to oak barrels. Part of the charm of a Sauvignon Blanc is its refreshing acidity, while the pleasures of a Chardonnay come from its rich, mouth-filling softness. Big-bodied reds, such as Cabernet Sauvignon, which are high in tannins and have a harsh, tart taste when young, obviously benefit most from this secondary fermentation.
Post-Fermentation Cellar Work:
Racking and ullage: Just as the grape juice for white wine was carefully filtered to remove any impurities prior to fermentation, so the red wine is filtered after fermentation. The fermentation itself kills the yeast and produces impurities called “lees” which fall to the bottom. Placed in oak barrels, partly to allow the malolactic fermentation—but also to permit the oak itself to impart its own
flavor of vanilla, caramel, and cream and to absorb the harshness of the tannins—the wine evaporates slightly in the barrel, thus concentrating its flavors. As the sediments (lees) settle to the bottom of the barrel, the wine is removed and poured into new barrels leaving the impurities behind, a process called “racking.” As the wine evaporates through the oak, it leaves an empty space at the top of the barrel which needs to be topped-up regularly with more wine to keep out the air, which would otherwise oxidize and spoil the wine. This process of topping-up is called “ullage.” Some white wines, such as Chardonnay, and most red wines, benefit from a certain amount of time in oak, especially those like Cabernet Sauvignon, which are high in tannins. Many of the great Châteaux wines of Bordeaux are aged in oak barrels for as long as two years before bottling. Spanish wines, in order to be classified as Crianza or Reserva, need to be aged in oak for at least six months. As discussed later in the chapter on Spain, the fortified wines of Jerez (Sherry) can be aged in barrels for one hundred years or more under the “solera” process. Oak barrels are discussed in more detail in the next section.
Blending and fining: Blending simply means combining wine from two or more sources and mixing them together. In blending the wines, the winemaker may be trying to enhance the aroma or improve the color, or to lower or raise the alcohol level, the sugar level, the acidity, or the tannins. The blended wines may come from the same vine and the same vintage when the vintner is adding pressed-wine to free-run wine to add more color, for example, but usually the blend will include wines from completely different sources and varietals when the vintner is trying to achieve a balance between the acidity, the tannins, and a lush fruitiness. The classic Bordeaux blend, for example, includes Cabernet Sauvignon for its tannins, Merlot for its softer fruitiness, Cabernet Franc for its earthiness, Malbec for its dark color, and Petit Verdot for its structure and body. In California, this particular blend is called
Meritage; while in England it is called Claret. The racking process, described above, removes most of the sediment from the wine, but fining agents are also added for the final clarification process, as they attract and attach themselves to the microscopic impurities which might otherwise cloud the wine. The most common fining agent is gelatin, but other traditional agents include bull’s blood, egg whites, bone char, and even honey.
Oak Barrels
Barrels have been used for transporting, storing, and aging wine since the time of the Romans. Even though modern wineries, with their focus on hygiene and efficiency, use stainless steel for most stages in the winemaking process, top quality wines still spend much of the time in old-fashioned oak barrels. The interaction between the wine and the oak is such an important part of the aging process that when storage in actual barrels is not economically feasible, oak chips are sometimes mixed with the wine in stainless steel vats as a way to imitate the benefit of barrel aging.
There is even an obscure historical relationship between oak and wine caused by the endless rivalry between the English and French. In 1615, England’s King James I banned the use of oak to fuel the furnaces used for making glass. The King wanted to preserve England’s oak forests for timber with which to build ships to invade France. Unable to use oak, England’s glassmakers started using coal in their furnaces, which created much higher temperatures—sufficient to melt sand and thus to produce modern wine bottles, which the French called verre anglais—strong enough to store sparkling wines and thus creating Champagne! Two hundred years later, Napoleon Bonaparte ordered the planting of five major forests of oak around France specifically for building a fleet of ships with which to invade England. These five forests now produce the world’s most expensive wine barrels.
Oak barrels offer three unique features: the wood itself absorbs and softens the wine’s natural tannins, thus hastening the aging process; the phenols in the oak also impart their own flavors of vanilla, caramel, spice, and smoke; and finally, the oak is porous, allowing the wine to breathe so that it slowly evaporates and thus concentrates its flavors. (This is why oak barrels have to be consistently topped-up.) Serious winemakers—lead by Robert Mondavi—put as much effort and research into selecting the oak for their barrels as they do in planting their vines or blending their wine. Slower growing forests produce tighter grain than forests with more sunshine and longer growing seasons. The tighter the grain of the oak, the more slowly the flavors are imparted; the looser the grain, the more quickly the oak will overwhelm the wine. Cellar masters will select the oak for their barrel depending on the style of wine they wish to make and the length of time they plan to age it.
Traditionally French oak, cut from the five forests planted by Napoleon I for ship-building, have always been favored over American oak, and the price of French versus American oak has reflected this. It has now been accepted that the difference lies not so much in the wood itself but in the way it was treated. The French air-dried their oak for at least two years before working it, while Americans saved time and kiln-dried their oak. To make the staves for the barrels, the Americans cut the wood with a saw, whereas the French always split it along the grain. The French methods imparted a much more subtle effect when aging the wine. Today, however, American wine barrel makers are using French methods and achieving similar results (although French oak is still more expensive).
Each time a barrel is used for aging, the wine will leave a coating of tartaric acid on the inside of the barrel so that after four or five uses the oak will have no further effect on the wine—it becomes a neutral oak barrel which is good for aging a lighter wine when the winemaker wants to retain the taste of fruit. The same is true for very large barrels, since a smaller proportion of the wine is in actual contact with the oak. The reason that German wines during the Middle Ages lasted for so long is that the Cistercian monks stored them in vast, giant barrels called tuns. Many of these tuns could hold over two hundr
ed thousand liters, or over fifty thousand US gallons of wine; indeed some, like the ones in Konigstein and Heidelburg, were so large that they had dance floors built on top of them. It was because the barrels were so vast and the insides so coated with tartaric acid that very little of the wine came into contact with the oak, and so they aged for decades without oxidizing.
However, for top quality, high-tannic wines where the oak is important, smaller barrels are used and used only once or twice before being sold off and replaced with new barrels so the wine can benefit from the intense notes of the fresh, uncoated oak.
The most common barrel size is the Bordeaux barriques style of 220 liters, followed by the slightly larger Burgundy style of 230 liters. Bordeaux’s high-tannin Cabernet Sauvignons require more intense oak than Burgundy’s Pinot Noirs, hence the smaller sized barrel. In 2011, the cost of a 220 liter French oak barrel was $850. A 220 liter barrel would thus produce almost 300 bottles of Bordeaux at a cost of about $2.90 per bottle. Obviously, this would be an excessive expense for the makers of Two Buck Chuck, but for a Château Latour with an average price of $775 per bottle, it is probably considered an acceptable expense.
Bottling and sealing
Sulphur dioxide is often added just prior to, as well as during, the bottling process, both as a preservative and also to prevent any further fermentation inside the bottle. As soon as the wine has been bottled, the neck is sealed with a cork, and, as a final step, a capsule is added.
The Booklovers' Guide to Wine Page 6