Viticulture & viniculture Flashcards
What is microbullage
Micro-oxygenation , an aeration technique in which small amounts of oxygen are allowed to enter a stainless steel tank during either fermentation or maturation of the wine, may be combined with oak chips to approximate the effects of a new barrel at a fraction of the cost.
What kind of wood is French oak produced from? American?
Quercus robur and Quercus petraea trees
American - Quercus alba - faster growing and wider grain, must releases more vanillan and coconut flavor
How do the following terms apply to barrel making: chauffage, citrange, and bousinage?
This process is divided into three stages: warming (chauffage), shaping (cintrage), and toasting (bousinage)—the latter stage has a significant effect on the wine.
What are the two basic methods of rosé winemaking?
Blending and limited skin maceration - Blending is regarded as inferior and prohibited throughout the EU, but only for wines below the PGI level!
What is saignée?
Known as the “bleeding” method, pink juice is drawn from a vessel to concentrate the remaining must for red wine production, improving its color and structure.
What is débourbage?
After pressing, the juice is allowed to settle - This process allows the juice to be racked off suspended solids and clarified prior to fermentation. During all of these procedures, warm temperatures and oxygen are the enemy, and winemakers must keep musts cool and prevent spoilage or premature fermentation with the judicious use of SO2.
What is cold stabilization?
A process that causes tartrate crystals to precipitate out of the wine at a temperature of approximately 25°F. In white wines that are not cold-stabilized, crystals may later form in the bottle.
What is whole cluster fermentation?
The fermentation of whole berries—a common practice with Pinot Noir and Syrah—will encourage a level of carbonic maceration, (stems may be retained for spicy aromatic complexity and structure) and requires less handling while improving the movement of juice and air through the cap. Damaged or unripe stems, however, can cause undesirable green flavors in the wine.
What is pigeage?
Punching down of the caps
What is anthocyanins? chapeau? of grape solids pomace?
A component in grape skins that creates red, blue, and purple hues.
chapeau-cap
Pomace-grape solids
What is remontage?
The fermenting wine is pumped over the top of the cap
What is délestage?
“rack and return”
A method of cap management in red wine production. The wine is racked into a separate vessel while the cap drains fully, and is then pumped back over the cap in the fermentation vessel. drain the fermentation vessel. The wine is racked into a separate vessel while the cap drains fully, and is then pumped back over the cap in the fermentation vessel.
What style of wine has juice still sitting on skins at least a month of post-fermentation maceration?
Nebbiolo-based wines in Piedmon
What is vin de goutte?
The high quality, free-run wine after fermentation and any post-fermentation maceration
What the difference between a traditional basket press and pneumatic press?
The traditional basket press relies on vertical pressure to press the pomace, whereas the modern pneumatic bladder press exerts gentle pressure on the grapes by means of its inflation with air.
What is elevage?
The maturation period ranges from a few months to more than two years, and the wines racked periodically during the process.
What is soutirage?
AKA racking, is the movement of wine from one vessel to another, providing aeration and clarification as the wine is removed from its lees, or sediment.
What is collage?
Fining
What are some fining agents?
Fining requires a fining agent to precipitate solids out of the wine: bentonite, casein, isinglass, gelatin, and egg white are commonly used.
Why would a winemaker choose to add diammonium phosphate to a fermenting must?
To prevent the formation of hydrogen sulfide
What is Cold Soaking?
A pre-fermentation maceration technique that relies on substantial SO2 additions and a cold temperature
What happens in the process of alcoholic fermentation?
The metabolism of yeast cells converts sugar in grape must into ethyl alcohol (ethanol) and carbon dioxide (CO2). Heat is generated during this process.
What natural volatile compounds are a product of Alcoholic fermentation, and affect the flavor of the wine?
Acetaldehydes, ethyl acetate and fusel oils…SO2 is a byproduct but is generally added to the fermenting must.
Why is sulfur dioxide (SO2) often added to a wines must prior to fermentation?
It prevents oxidation and bacterial contamination, and to ensure rapid fermentation
What is the temperature range the yeast will live at?
Below 50°F, most yeasts will not act; above 113°F, yeasts will die.
In regard to small vessels verse large vessels for fermentation, which creates a short and cool fermentations, and which creates hot and long fermentations?
Short hot - large
long cool - small
What is happening in malolactic fermentation? What does it do to the wine?
In malolactic fermentation, lactic acid bacteria convert harsh malic acids into softer lactic acids and carbon dioxide. It rounds out a wine’s texture.
Which comes first - alcoholic or malolactic?
Alcoholic fermentation… Malolactic is also known as secondary fermentation
What is responsible for buttery aromas in wine, and is a byproduct of malolactic fermentation?
Diacetyl
How does malolactic fermentation start?
Malolactic fermentation may be initiated by inoculation, or it may occur naturally, as lactic acid bacteria are naturally found alongside yeasts on grape skins.
What is macération carbonique and how does it work?
Carbonic maceration - whole, uncrushed grapes in an anaerobic environment (under a protective blanket of CO2) initiate an intracellular fermentation. Attempting to sustain itself, a berry will release enzymes to transform its own sugar into ethanol and carbon dioxide. This occurs without the action of yeasts.
How does carbonic maceration affect the alcohol of a wine?
Alone, it cannot produce more than a couple of degrees of alcohol, as the berry ceases activity in the presence of enough ethanol. Carbonic maceration must therefore be combined with a standard fermentation in wine production.
Briefly describe how nouveau wines are made.
A tank will be filled with whole berries. Berries at the bottom will be crushed under the weight of those above it, and will ferment normally. The ensuing carbon dioxide will blanket the whole berries above, which will then begin to ferment by carbonic maceration. The grapes will eventually explode, or the winemaker will press the juice, and then the yeasts would begin their work.
What is chaptalization and where/why is it used?
The addition of sugar to the must to increase the final alcohol and glycerin content of the wine - cooler temperatures, especially the Old World
What are some techniques to lower alcohol? What areas would do this?
Modern devices such as spinning cones or reverse osmosis. Warmer areas- especially New World?
How does reverse osmosis lower a wines alcohol?
It separates the wine into two constituent parts, permeate and retentate. The permeate, which contains water and ethanol, is then distilled to a proper level before being recombined with the retentate—the wine’s aromatic compounds—at a lower percentage of alcohol.
When did the EU legalize de-alcoholization again? How much is allowed to be adjusted now?
Legalized in 2009, provided the level of alcohol is not adjusted by more than 2%
What is acidification? What acids are used?
Tartaric acid and malic acid, the two principle acids in grape juice, may be used for acidification; tartaric acid, added prior to fermentation, is preferred.
What two genres of yeast are used in winemaking? What are their difference is regards to dependability and influence on the final wine?
Cultured yeasts - lab made- promise reliability, and are often able to continue to work in higher levels of alcohol than ambient yeasts.
Ambient yeasts—often inaccurately identified as “native” or “wild”—inhabit the winery and come to life in the presence of must - less predictable than cultured yeasts. Many winemakers believe ambient yeasts create a more complex wine.
How long does it take for a wine to ferment to dry? What is the major variable?
Depending on the type of yeast used, the wine will take as little as a week to more than a month to ferment dry.
What is Acetaldehyde?
regarded as a sign of oxidation in finished wines - the last link on the chain of intermediate compounds between sugar and alcohol, and will remain in the new wine in trace amounts
What are the differences in fermentation temperature between red and white wines?
White wine fermentations usually take place on the cooler end, as fruit and freshness are preserved at lower temperatures. Red wine fermentations may reach into the 90s, although winemakers run the risk of volatized (lost) flavor compounds and stuck fermentations as the thermometer passes 95°F.
What is bâtonnage?
lees stirring, generally in a barrel - which add further complexity and richness.
How does acetic acid relate to VA?
A small amount of the remaining acetaldehyde is inevitably converted to acetic acid, which in turn reacts with alcohol to produce ethyl acetate, a culprit of volatile acidity in wine
What is acetobacter?
The group of bacteria responsible for turning wine to vinegar in the presence of oxygen
What fault is created of low levels of nitrogen in the must? What are the characteristics of the wine if this happens?
Yeasts require nitrogen to work, and low levels of nitrogen in the must leads to the formation of hydrogen sulfide (H2S), a highly volatile compound reminiscent of rotten eggs.
What does “sulfites” mean and what does this do to the wine?
In winemaking terms, the addition of “sulfites” refers to sulfur dioxide (SO2); “sulfides” include hydrogen sulfide (H2S), mercaptans and other foul-smelling compounds produced under reductive conditions.
What led the growth of agricultural advancements in viticulture in the 20th century?
The 20th century witnessed a series of great agricultural advancements—many of which grew from wartime applications—as modern chemistry paved the way for successful monoculture. The discovery of synthetic nitrogen led to the development of chemical fertilizers, a Nobel Prize-winning endeavor blemished by its subsequent use in the poison gases of World Wars I and II.
When did the EU ban GMOs? What form of a GMO does the USA employ?
GMOs (genetically modified organisms) have been banned in the EU since 1998, but genetically modified yeasts were first employed in North American winemaking in 2006.
In order to grow grapes organically in the US or Australia, synthetic chemical treatments and certain filtration procedures are forbidden—although _______ and _________ may still be allowed.
Copper and sulphur treatments (such as a Bordeaux mixture?
What is the difference between organic wine and organically grown wine?
When an American (or Australian) wine is labeled as “organic”, it must be produced from organically-grown grapes and contain no added sulfites—a stipulation which prevents most good bottles from qualifying, as sulfites are an important (and almost universal) preservative in wine. Instead, many bottles are labeled as “wine made from organically grown grapes”, a designation which permits the addition of sulfites
How much of Californias production is organically grown?
Despite the image of “green”, less than 10% of California’s wineries use any organically grown grapes.
Describe the concept of Biodynamic viticulture
Takes the concepts of organic and sustainable farming and combines them with an almost mystical sensibility. Observing the rhythms and forces of the Earth is, in the ideal of biodynamic farming, intrinsically tied to the success of any ecosystem—the farm, in concert with the cosmic periphery, becomes a whole organism, generating its own fertility as governed by the cycle of seasons and lunar activity. Truly biodynamic vineyard workers will time their various tasks by motions of celestial bodies—particularly the moon.
Who brought forth the concept of biodynamics and when? Who is an excellent example of a biodynamic producer in the Loire Valley today?
Introduced by the Austrian Rudolf Steiner in 1924 and today personified by Nicolas Joly of the Loire
Who internationally certifies farms and vineyards in Biodynamics?
The Demeter Biodynamic Trade Association certifies biodynamic farms and vineyards internationally.
What kind of practices are implemented in biodynamic agriculture?
Biodynamic agriculture requires the yearly application of homeopathic preparations, produced from such animal and mineral substances as dandelion flowers, stinging nettles, and “horn manure” to ritually treat and heal the soil. Biodiversity and soil rotation are emphasized.
