NU FS 402 Quiz 2 || 100% Correct Answers.
What effects wine quality and aroma? correct answers - the vine: location, variety, climate,
determines microbiome
- grapes (smaller grapes, bigger flavor)
- crushing of the grapes
- fermentation
-oat and microbial-derived compounds
-microbial-derived compounds
What plant diseases can affect grapes? correct answers Fungal: can be controlled, found
everywhere
-Plasmopara viticola downy mildew: if it rains right before harvest
-Uncinula necator powdery mildew
-phylloxera root lice: eats the roots of the grapevine, only eats 1 variety -> vitis vinifera (can be
controlled by using a different grape root underneath the vitis vinifera)
How can we control insects in a grape vineyard? correct answers - flowers are planted by the end
of all the rows to attract bugs (alternate to insecticide)
What is the grape variety used for wine? correct answers vitis vinifera
What are the ideal conditions for growing grapes for wine? correct answers - climate: warm, less
acid sweet (can't be too acidic)
- rainfall: if it rains at the wrong time = you can get fungus (right before its picked) but you still
need it for water
- soil: well-drained, low fertility
-canopy management: sun, light, and air (right amount of shade) Y, V, T shape
What is malolactic fermentation? correct answers Secondary fermentation in which harsh, malic
acid is converted to softer, lactic acid
What kind of acid is present in grapes? correct answers - tartaric and malic acid (3.1-3.5)
What sugars are present in grapes? correct answers - polymer of galaturonic acid
What are some other contents in grapes and what are they for? correct answers - phenolic
compounds: fruity smells, astringency (see phenolic compounds)
-nitrogenous substances: need it for yeast to grow (sometimes will add ammonia for yeast to
grow)
-thiol precursors: non-volatile until fermentation smelly
- methoxypyrazines: herbaceous aromas (green pepper aroma)
What affect does phenolic compounds have on wine aroma and flavor? correct answers -
nonflavonoids: phenolic acids, tyrosol, volatile phenolics (aroma)
, -flavonoids: catechin (browning, bitter), flavonols (polymerize to form tannins that are astringent
and bitter), anthocyanins (color)
How are phenolic acids made in wine? correct answers - first occur in the grape as esters with
tartaric acids
- coumaric and ferulic generate volatile phenols
-formed during fermentation
-decarboxylation by cinnamate decarboxylase (CD)
-S. cerevisiae cause CD to be inhibited by catechins present in red wine
-when Brettanomyces is in the wine it does not inhibit CD (YOU DO NOT want this in your
wine)
-volatile phenols are higher in white/rose wines except red wines affected by Brettanomyces
-courmaric (4-vinyl phenol) + ferulic (4-vinyguaiacol) give a medicinal off odor and flavor
Where are anthocyanins most present in the grape? correct answers the skin and seeds = red
color (pH independent)
What is the color of wine dependent on? correct answers -anthocyanins in wine
-amount of anthocyanin depends on grape variety: malvidin 90% of anthocyanins in Grenache
(used to color wine) 50% of anthocyanins in Sangioviese
-anthocyanins depend on extraction and winemaking techniques
-also depend on stage of fermentation/aging (anthocyanins will adsorb on yeast cell walls as well
as precipitate with tartaric acids and tannins)
Why does wine turn orange sometimes? correct answers -anthocyanins can polymerize with
tannins over time making an orangy color.
Why does wine get sludge? correct answers You can get sludge at the bottom of the bottle also
from anthocyanins polymerizing with tannins over time. Sludge will also pull out some
astringency and acid. This will also help clarify the wine as these sink to the bottom.
What part of the grape has the most tannins? correct answers -the seed
what are terpenoids? correct answers derivatives of terpenes that have undergone oxygenation or
rearrangement of the carbon skeleton
- most significant aromas precursor in many grapes
How do we make monoterpenes? correct answers 2 step enzymatic hydrolysis involving 2
different enzymes
B-D-glucosidase, to cleave beta-d-glucose to turn a precursor (linalool sugar-bound aglycone)
into linalool
-linalool gives this beautiful floral flavour
How is wine flavour developed? correct answers - grape as formed by the plant
- compounds modified by processing
- compounds formed by yeast during alcoholic fermentation
What effects wine quality and aroma? correct answers - the vine: location, variety, climate,
determines microbiome
- grapes (smaller grapes, bigger flavor)
- crushing of the grapes
- fermentation
-oat and microbial-derived compounds
-microbial-derived compounds
What plant diseases can affect grapes? correct answers Fungal: can be controlled, found
everywhere
-Plasmopara viticola downy mildew: if it rains right before harvest
-Uncinula necator powdery mildew
-phylloxera root lice: eats the roots of the grapevine, only eats 1 variety -> vitis vinifera (can be
controlled by using a different grape root underneath the vitis vinifera)
How can we control insects in a grape vineyard? correct answers - flowers are planted by the end
of all the rows to attract bugs (alternate to insecticide)
What is the grape variety used for wine? correct answers vitis vinifera
What are the ideal conditions for growing grapes for wine? correct answers - climate: warm, less
acid sweet (can't be too acidic)
- rainfall: if it rains at the wrong time = you can get fungus (right before its picked) but you still
need it for water
- soil: well-drained, low fertility
-canopy management: sun, light, and air (right amount of shade) Y, V, T shape
What is malolactic fermentation? correct answers Secondary fermentation in which harsh, malic
acid is converted to softer, lactic acid
What kind of acid is present in grapes? correct answers - tartaric and malic acid (3.1-3.5)
What sugars are present in grapes? correct answers - polymer of galaturonic acid
What are some other contents in grapes and what are they for? correct answers - phenolic
compounds: fruity smells, astringency (see phenolic compounds)
-nitrogenous substances: need it for yeast to grow (sometimes will add ammonia for yeast to
grow)
-thiol precursors: non-volatile until fermentation smelly
- methoxypyrazines: herbaceous aromas (green pepper aroma)
What affect does phenolic compounds have on wine aroma and flavor? correct answers -
nonflavonoids: phenolic acids, tyrosol, volatile phenolics (aroma)
, -flavonoids: catechin (browning, bitter), flavonols (polymerize to form tannins that are astringent
and bitter), anthocyanins (color)
How are phenolic acids made in wine? correct answers - first occur in the grape as esters with
tartaric acids
- coumaric and ferulic generate volatile phenols
-formed during fermentation
-decarboxylation by cinnamate decarboxylase (CD)
-S. cerevisiae cause CD to be inhibited by catechins present in red wine
-when Brettanomyces is in the wine it does not inhibit CD (YOU DO NOT want this in your
wine)
-volatile phenols are higher in white/rose wines except red wines affected by Brettanomyces
-courmaric (4-vinyl phenol) + ferulic (4-vinyguaiacol) give a medicinal off odor and flavor
Where are anthocyanins most present in the grape? correct answers the skin and seeds = red
color (pH independent)
What is the color of wine dependent on? correct answers -anthocyanins in wine
-amount of anthocyanin depends on grape variety: malvidin 90% of anthocyanins in Grenache
(used to color wine) 50% of anthocyanins in Sangioviese
-anthocyanins depend on extraction and winemaking techniques
-also depend on stage of fermentation/aging (anthocyanins will adsorb on yeast cell walls as well
as precipitate with tartaric acids and tannins)
Why does wine turn orange sometimes? correct answers -anthocyanins can polymerize with
tannins over time making an orangy color.
Why does wine get sludge? correct answers You can get sludge at the bottom of the bottle also
from anthocyanins polymerizing with tannins over time. Sludge will also pull out some
astringency and acid. This will also help clarify the wine as these sink to the bottom.
What part of the grape has the most tannins? correct answers -the seed
what are terpenoids? correct answers derivatives of terpenes that have undergone oxygenation or
rearrangement of the carbon skeleton
- most significant aromas precursor in many grapes
How do we make monoterpenes? correct answers 2 step enzymatic hydrolysis involving 2
different enzymes
B-D-glucosidase, to cleave beta-d-glucose to turn a precursor (linalool sugar-bound aglycone)
into linalool
-linalool gives this beautiful floral flavour
How is wine flavour developed? correct answers - grape as formed by the plant
- compounds modified by processing
- compounds formed by yeast during alcoholic fermentation
