Lecture 13: Alcohol 1 Flashcards
_______ is a biological process in which sugars from plants (e.g., glucose, fructose, and sucrose) are converted into cellular energy, ethanol and carbon dioxide as metabolic waste products.
Alcoholic fermentation (ethanol fermentation)
True or False: Because yeasts perform this conversion in the absence of oxygen, alcoholic fermentation is an anaerobic process.
True
Alcohol fermentation was discovered by?
1810 by Gay-Lussac
What 3 things did alcohol fermentation lead too?
Production of alcoholic beverages
Rising of bread dough
Ethanol fuel
How could birds get drunk?
Particularly fruits that are damaged (i.e. the skin is broken) are colonised by S. cerevisiae, which is transmitted by bees, wasps, and Drosophila.
True or False: Most important civilizations empirically discovered fermentation and produced an alcoholic beverage from grapes (wine) or from other fruits (cider) was probably accidental.
True
______ is a liana (woody vine) with tendrils and palmate leaves
The grape wine
Vitis vinifera
What is the fruit of wine?
Berry
True or False: Wine was domesticated independently at least 2 times.
True
Transcaucasia and W Mediterranean area.
_____ earliest wine making in Europe.
Greeks (ca. 6500 ya.)
_______ developed cultivation on trellises, making white and red wine (5000 y old sealed wine jars found in tombs).
Egyptians
_______ classified grape varieties and made many innovations: developed the press, barrels, adding spices and herbs to the wine
Romans
_______ = the science of growing grapes (Vitis vinifera)
_______ = the science of making wine
Viticulture
Oenology
_______ was the Greek god of the grape harvest, winemaking and wine, of ritual madness and ecstasy in Greek mythology.
________ is the Roman equivalent , the god of wine and intoxication
Dionysus
Bacchus
True or False: Dionysus thus came to be considered a patron of the arts
True
_______ introduced wine making and wine to France, Germany, England
Romans
One was one of the first grapes introduced to California in 1769 by Father Junipero Serra?
Mission grape
The time of harvest is determined primarily by the _______ and _______.
content in sugar (15—20% glucose and fructose)
acid
Sugars are stored in the ______ along with water, organic acids and other compounds.
Pigments are stored in the _______.
Tannins are present in the _____.
pulp (mesocarp)
epicarp (“skin”)
seeds
_______ is the process required to gently squeeze the berries and break the skins to liberate the grape juice.
Crushing
The resulting mix of skins, juice and seeds is called ______.
must
_______ squeezes the skins the extract the remaining liquid and separates it from the skins and seeds.
Pressing
Red wines are produced by leaving skins in contact with the juice (_______)throughout the fermentation
(maceration)
How are white wines made vs red wines?
With white wines, grapes are crushed, pressed and then fermented.
With red wines grapes are crushed, macerated-fermented, and then pressed to remove the skins.
True or False: Fermentation ends when there are no more sugars in the wine.
True
______ is added to juice to inhibit the growth of unwanted yeasts and bacteria brought in with the grapes and removing oxygen from the fermentation vats insuring that Acetobacter spp. will not turn the resulted ethanol into acetic acid
SO2
If higher concentrations of alcohol are desired, the wine must be _______.
fortified or distilled.
_______ may involve filtration, centrifugation, refrigeration.
_______ involves pasteurization, and/or treatment with sorbic acid.
Clarification and stabilization
Stabilisation
Malolactic fermentation occurs when lactic acid bacteria (Lactobacillus spp.) metabolize ______ and produce ______ and ______
malic acid
lactic acid and carbon dioxide
Happens in all red wines and some white
True or False: bottles that are often flushed with N to minimize exposure to oxygen
True
_______Is an aerobic fermentation in which alcohol is converted into acetic acid (vinegar) by bacteria of the genus Acetobacter, esp. A. aceti
Acetic fermentation
True or False: Research shows that people’s enjoyment of wine is influenced by how much it costs
True
True or False: A third alcoholic fermentation is necessary to produce CO2 in the wine. The classical method (developed in the Chapagne region is to do that directly in the bottle.
False, second
Sediments from the 2nd fermentation accumulate in the cap and they are eliminated through a process called _______
disgorgement
True or False: You want to buy a sparkling wine in which CO2 results from a second fermentation not from CO2 injected, soda-like wine
True
The bubbles are finer and the fizz lasts longer.
_______ wines are wines which are added alcohol (usually brandy) to make them stronger (15-21% ethanol) and the additional ethanol acts as a preservative.
Fortified
True or False: In Canada, per capita consumption of wine has been rising slowly and steadily for years and Canadians currently go through about 6 litres of wine per capita
False, 13 L per capita
