Objectives

2. Objectives • After reading this chapter, you should be able to • display an understanding of how both red and white table wines are produced. • describe how sparkling wine is produced. • explain how dessert wines are produced. © 2007 Thomson Delmar Learning. All Rights Reserved.

3. Introduction • Great wines begin in the vineyard, but they are finished at the winery. • Like a chef, the winemaker works with flavors and aromas to create a wine that consumers will enjoy. • The decisions the winemaker makes may appear random in nature, but in reality they are based on a scientific understanding of the techniques used to produce wine. © 2007 Thomson Delmar Learning. All Rights Reserved.

4. Introduction (continued) • Complicating the winemaker’s quest to create great wine is the fact that people have different tastes and preferences, and there is no one “ideal” style wine. • During the 6,000-year history of wine-making, its production has evolved into a number of complex procedures that produce a variety of wines. © 2007 Thomson Delmar Learning. All Rights Reserved.

5. Introduction (continued) • Table wine is a wine designed to accompany food. It is produced in numerous forms, both red and white. • It is the most common type of wine consumed in the United States, making up over 90 percent of the market. • A table wine is a still wine (a wine without effervescence). • A table wine is also relatively dry (without sweetness). • It has a moderate alcohol content of about 11 to 15 percent. © 2007 Thomson Delmar Learning. All Rights Reserved.

6. Introduction (continued) • In the United States, a wine must be less than 14 percent alcohol to be labeled a “table wine.” • This number was chosen for reasons of tax collection, not the true definition of being a wine made to complement food. • Grapes are usually picked at 22 to 25 degrees Brix (°B) to obtain this alcohol level. • Brix is equal to the percentage of sugar by weight. © 2007 Thomson Delmar Learning. All Rights Reserved.

7. The Process of Fermentation • Fermentation is the process of yeast, unicellular (one-celled) fungi, converting the sugar in grape juice to alcohol and carbon dioxide. • Other microorganisms can do this, but yeast ferment with the most efficiency and can survive in the higher alcohol at the end of fermentation. © 2007 Thomson Delmar Learning. All Rights Reserved.

8. The Process of Fermentation • The species of yeast that is best suited for winemaking is called Saccharomyces cerevisiae. • The name Saccharomyces is derived from the Latin sugar-fungus; cerevisiae refers to grain. • Saccharomyces cerevisiae’s most common use is in bread making. © 2007 Thomson Delmar Learning. All Rights Reserved.

9. The Process of Fermentation • The rate of fermentation is affected by a number of factors, including • temperature—the warmer the juice is, the faster it will ferment. • However, above 100°F, yeast will die off. • acidity—the higher the concentration of acid (the lower the pH), the slower the rate of fermentation. © 2007 Thomson Delmar Learning. All Rights Reserved.

10. The Process of Fermentation(continued) • nutrients—if the juice is low in nutrients, the yeast may not be able to ferment to dryness. • alcohol—at higher concentrations, 13 percent to 16 percent depending on strain, yeast begin to die. • sugar—although sugar is required for yeast growth, if the sugar concentration is greater than 30 percent, it inhibits yeast growth. © 2007 Thomson Delmar Learning. All Rights Reserved.

11. Natural Fermentation • Wine was made for thousands of years before there was knowledge of such things as microscopic organisms called yeast. • Although early winemakers did not understand the mechanism, they knew how to use it to produce wine. • Some wineries use natural or “wild” yeast that live on the grape skins to make wine. © 2007 Thomson Delmar Learning. All Rights Reserved.

12. Natural Fermentation (continued) • “Wild” yeast can give the wine more complexity, but there also is a higher risk of off-flavors or incomplete fermentation. • Today most winemakers use commercially available strains of yeast. • These yeasts are similar appearance to baker’s yeast, and they give the winemaker a clean, efficient fermentation. © 2007 Thomson Delmar Learning. All Rights Reserved.

13. Harvest • Grapes must be harvested and processed as soon as they reach their peak of flavor. • The weather conditions set the pace of harvest. • Once the grower and the winemaker have determined that the grapes have reached their optimum ripeness and flavor, they are picked and brought to the winery. • At the winery the crop is weighed, inspected, and analyzed before being processed. © 2007 Thomson Delmar Learning. All Rights Reserved.

14. Red Wine Crush and Fermentation • After the grapes are weighed and inspected, they are brought to the receiving hopper and unloaded. • At the bottom of the hopper, there is either a screw or a belt conveyor that is used to transport the fruit to the stemmer-crusher. © 2007 Thomson Delmar Learning. All Rights Reserved.

15. Red Wine Crush and Fermentation(continued) • The stemmer-crusher has two functions: first it takes the berries off the stems, and second it breaks the berries open to release the juice. • The stemmer portion separates the berries from the stems. • The crusher breaks open the berries and releases the juice. © 2007 Thomson Delmar Learning. All Rights Reserved.

16. Red Wine Crush and Fermentation(continued) • The mixture of approximately 80 percent juice, 16 percent skins, and 4 percent seeds produced by the crusher is called must. • At this point, the must is liquid enough to be pumped to a tank for fermentation. • In modern wineries, fermentation tanks are usually made of stainless steel, although vats made of wood or concrete are also still in use. © 2007 Thomson Delmar Learning. All Rights Reserved.

17. Red Wine Crush and Fermentation(continued) • After the tank is loaded, the must is analyzed and adjusted if necessary. • The compounds that are added to adjust the must are natural and already present in the must to some degree, such as sugar, acid, nutrients, and yeast. • The exception to this is the preservative sulfur dioxide. © 2007 Thomson Delmar Learning. All Rights Reserved.

18. Red Wine Crush and Fermentation(continued) • Additives to wine are regulated and vary from region to region. • For example, it is legal to add sugar to must in France but not acid, whereas in California the opposite is true. © 2007 Thomson Delmar Learning. All Rights Reserved.

19. Red Wine Crush and Fermentation(continued) • Once the fermentation begins, the carbon dioxide that is evolved causes the skins to float to the top of the tank and form a cap. • The juice from most red wine varieties is clear, so it is necessary to extract the red color out of the skins to make red wine. • If the skins are in a cap that is floating above the juice, very little extraction will take place. © 2007 Thomson Delmar Learning. All Rights Reserved.

20. Methods of Cap Management • To combat extraction problems, the cap is mixed into the juice several times a day. • The manner in which it is mixed, and the frequency, have a major effect on the overall style of the wine being made. • Punching down is the oldest, simplest method of mixing the cap of skins and the juice. A punch-down device is used to press down the cap into the juice. © 2007 Thomson Delmar Learning. All Rights Reserved.

21. Methods of Cap Management(continued) • Pumping over is where juice is irrigated over the top of the cap. • As the juice percolates through the skins, it extracts the color and flavor. • Rotary fermentors are the most modern and least labor-intensive method. • They are large horizontal tanks that are rotated and so the cap is rolled over into the juice. © 2007 Thomson Delmar Learning. All Rights Reserved.

22. Methods of Cap Management(continued) • Carbonic maceration is where a portion or all of the grapes are not crushed but loaded into the tank as whole clusters. • As the fermentation in the juice progresses, it also begins to take place within the cells of the intact grape berries. • This produces soft tannins and a unique strawberry or bubble gum aroma. © 2007 Thomson Delmar Learning. All Rights Reserved.

23. Methods of Cap Management(continued) • Extended maceration is more suited to big-bodied red wines such as Cabernet Sauvignon. • In this technique, at the end of fermentation the must is not pressed, and the skins are left in contact with the young wine from 1 to 8 weeks. • This method is used to give big-bodied wines less tannins. © 2007 Thomson Delmar Learning. All Rights Reserved.

24. Red Fermentation • Red wines ferment at 75° to 90°F; at this temperature, there is optimal extraction of color without harming the yeast. • Fermentation usually takes from 1 to 3 weeks at this temperature. © 2007 Thomson Delmar Learning. All Rights Reserved.

25. Pressing the Skins • In red wines, when fermentation is complete and the winemaker is satisfied with the flavor extraction, it is time to separate the wine from the skins. • The majority of the wine is simply drained out of the tank by gravity; however, 10 to 20 percent is held within the skins still inside the tank. © 2007 Thomson Delmar Learning. All Rights Reserved.

26. Pressing the Skins (continued) • The skins are then removed from the tank and loaded into a press, which squeezes out their remaining liquid. • There are a number of types of presses, but they all work in the same manner. • Force is applied to a layer of skins against a screened or slatted surface that allows the juice through but holds the skins and seeds back. © 2007 Thomson Delmar Learning. All Rights Reserved.

27. Types of Presses • The basket press is the oldest and most simple design. • It is a vertical cylinder made of slats of wood arranged with small gaps in between them. • Traditional basket presses are gentle but require the cake to be broken up by hand in between press cycles. © 2007 Thomson Delmar Learning. All Rights Reserved.

28. Types of Presses (continued) • Tank presses are cylindrical steel tanks that are 3 to 8 feet in diameter and are mounted horizontally. • On one side of the interior, there is an inflatable bag or membrane, and on the other side is a series of perforated screens or channels. • The bag inflates squeezing the skins against the screens to remove the juice. © 2007 Thomson Delmar Learning. All Rights Reserved.

29. Press Fractions • Free run is the first wine to come off during pressing and it is the highest-quality juice. • Press fraction—As the cycles of pressing go on, the quality of the juice diminishes becoming more astringent and bitter. • The young wine is then collected in a sump at the base of the press before being pumped into a receiving tank. • After the skins dry, they are called pomace. © 2007 Thomson Delmar Learning. All Rights Reserved.

30. Settling and Racking • Yield after fermentation is typically about 170 gallons of wine per ton of grapes. • After pressing, the wine is pumped to a tank in the winery cellar for storage. • At this point the new wine is very turbid and full of suspended solids such as yeast cells, particles of grape skins, and pulp. © 2007 Thomson Delmar Learning. All Rights Reserved.

31. Settling and Racking (continued) • After several days, the suspended solids begin to settle out to the bottom of the tank forming a layer of thick mud-like material called lees. • After a week or two the clean wine is decanted off the layer of lees in a process called racking. © 2007 Thomson Delmar Learning. All Rights Reserved.

32. White Wine Crush and Fermentation • White wines are made from white (green skinned) grape varieties. • Because the juice of most red grapes is colorless, it is also possible to make a white wine from red grapes as is done with White Zinfandel and Blanc de Noir sparkling wine. • Red wines receive most of their flavor from the skins, and whites get theirs from the juice. © 2007 Thomson Delmar Learning. All Rights Reserved.

33. White Wine Crush and Fermentation(continued) • The most important difference in processing is that red wines are pressed after fermentation and white wines are pressed before. • White are usually picked early in the morning and brought to the winery while they are still cool to preserve the fresh fruit flavors. © 2007 Thomson Delmar Learning. All Rights Reserved.

34. White Wine Crush and Fermentation(continued) • In white winemaking, the grapes are picked, weighed, inspected, and unloaded into the receiving hopper much in the same way they are for red wine production. • After they are picked, red and white winemaking techniques diverge and the juice must be separated from the grapes. © 2007 Thomson Delmar Learning. All Rights Reserved.

35. White Wine Crush and Fermentation(continued) • The fruit can be • crushed and pressed. • This is similar to the way red grapes are handled except the pressing takes place prior to fermentation. • crushed, dejuiced, and pressed. • Here the juice is drained out by gravity between crushing and pressing. • whole cluster pressed. • Uncrushed clusters are pressed directly—the most gentle method. © 2007 Thomson Delmar Learning. All Rights Reserved.

36. White Wine Fermentation • After pressing, the juice is pumped to a settling tank. • The juice is kept cool, at around 50°F, and held in the settling tank for 12 to 72 hours to allow the lees to form. • The juice is racked off the grape solids, or primary lees, to avoid the production of undesirable flavors during fermentation. • In the fermentation tank, yeast and fermentation additives are added. © 2007 Thomson Delmar Learning. All Rights Reserved.

37. White Wine Fermentation(continued) • White wine fermentations take place at a cool temperature, 45° to 60°F, to help retain its fruity aromas. • White fermentations take two to three times as long as red fermentations, about 3 to 6 weeks. • After fermentation, the new wine is racked off the yeast lees. © 2007 Thomson Delmar Learning. All Rights Reserved.

38. Barrel Fermentation • Barrel fermentation of white wine gives it a distinctly toasty aroma and is very popular with Chardonnay. • After the fermentation is finished, the barrels are topped off and the wine is left in contact with the yeast lees at the bottom of the barrel. • This technique of aging is called sur lie (French for “on the lees”). © 2007 Thomson Delmar Learning. All Rights Reserved.

39. Barrel Fermentation (continued) • Sur lie aging: • This gives the wine more of a yeasty-bready aroma and more viscosity. • The young wine can be left sur lies for many months; sometimes the yeast is periodically stirred to intensify the character. © 2007 Thomson Delmar Learning. All Rights Reserved.

40. Malolactic Fermentation • The most prevalent acids in wine are tartaric acid and malic acid. • Malolactic bacteria convert malic acid in wine into lactic acid. • Malolactic fermentation has several effects on the wine, • De-acidification, malic acid is a stronger acid than lactic • Microbial stability, if malo-lactic finishes during aging it will not spoil the wine by taking place in the bottle. • Malolactic fermentation produces a compound called diacetyl that has a distinct buttery character. © 2007 Thomson Delmar Learning. All Rights Reserved.

41. Malolactic Fermentation (continued) • Malolactic fermentation usually takes place after the primary, or alcoholic, fermentation and occurs at a much slower pace. • Malolactic fermentation is usually encouraged in red wines for reasons of stability. • With white wines, it is a stylistic concern. • In a light-bodied fruity wine like Riesling, it is usually avoided, while in a rich oak-aged Chardonnay it would be more appropriate. © 2007 Thomson Delmar Learning. All Rights Reserved.

42. Barrels and Aging • The first to store wine in barrels were the Romans. • Winemakers soon discovered that storing wine in barrels had positive effects on the wine’s flavor. • Barrel makers are called coopers. • There are two types of reactions that are taking place during aging: • The wine undergoes a slow oxidation. • Flavor components are absorbed from the wood. © 2007 Thomson Delmar Learning. All Rights Reserved.

43. Barrels and Aging (continued) • Oak is the chosen wood for wine barrel production. • It is strong and durable; it is also nonporous, so the barrels will not leak. • It also has excellent flavor and aroma compounds that are extracted into the wine. © 2007 Thomson Delmar Learning. All Rights Reserved.

44. Barrels and Aging (continued) • The two major categories of oak are European and American. • There are two species of European oak that are used for making wine barrels, Ouercus sessilis and Quercus robar; they are grown throughout France and central Europe. • European oak is known for giving wine a rich, toasty vanilla aroma. © 2007 Thomson Delmar Learning. All Rights Reserved.

45. Barrels and Aging (continued) • In America Quercus alba, or white oak, is used for barrel making and has stronger, more woody flavors than European oak. • Beyond the type of oak used, a barrel’s flavor varies depending on the forest the wood is from and the various methods of production that different coopers use. © 2007 Thomson Delmar Learning. All Rights Reserved.

46. Barrels and Aging (continued) • Much of the flavor obtained from aging wine in barrels comes from what is extracted out of the oak; however, the softening of the wine’s texture that comes with aging is due to the process of slow oxidation. • Oak has the quality of being semipermeable to oxygen allowing a small amount of oxygen to be incorporated in an aging wine. • This helps tannin molecules to polymerize and settle out, softening a wine's body and making it less bitter. © 2007 Thomson Delmar Learning. All Rights Reserved.

47. Barrels and Aging (continued) • During aging, a small amount of alcohol and water in the wine can evaporate through the oak of the barrel. • This evaporation causes the remaining wine in the barrel to become more concentrated with acid and flavor. • From time to time, the ullage (headspace in the barrel) that is produced by this evaporation must be displaced by topping the barrel up with wine from the same lot. © 2007 Thomson Delmar Learning. All Rights Reserved.

48. Finishing a Wine • After aging is complete, the wine is pumped out of the barrel and sent to the tank cellar for preparation for bottling. • Wines can be bottled from a single fermentation lot, but more often different lots are blended together. © 2007 Thomson Delmar Learning. All Rights Reserved.

49. Finishing a Wine (continued) • After the blend is selected, two more steps must be completed before wine is ready to be bottled: • Clarification produces a wine that is brilliant and free of suspended solids. • Stability operations are performed to ensure that a brilliant wine stays so. © 2007 Thomson Delmar Learning. All Rights Reserved.

50. Clarification and Fining • The simplest and most gentle form of clarification is settling and racking. • Fining is the process of adding a compound called a fining agent to the wine that will react with compounds in the wine causing them settle out. • After the wine settles, the fining agent and the wine component that it removed are left behind in the lees when the wine is racked. © 2007 Thomson Delmar Learning. All Rights Reserved.