Knowledge Gap Cards

Question 1

All grand crus and main premier crus of Chablis

Answer 1

Grand Crus (7): Bougros, Les Preuses, Vaudésir, Grenouilles, Valmur, Les Clos, Blanchot
Premier Crus (17 main climats from 40): Mont de Milieu, Montée de Tonnerre, Fourchaume, Vaillons, Montmains, Côte de Léchet, Beauroy, Vaucoupin, Vosgros, Vau de Vey, Vau Ligneau, Les Beauregards, Les Fourneaux (Less used: Côte de Vaubarousse, Berdiot Côte de Jouan, Chaume de Talvat)

Question 2

Wine fermenting temperatures: White / Rose / Red

Answer 2

12-22 for whites
20-32 for red

Question 3

Sherry Region: DO, subregions

Answer 3

DO Jerez-Xeres-Sherry, DO Manzanilla - Sanlucar de Barrameda, PX = Montilla

Question 4

Explain albariza soil

Answer 4

mixture of limestone, clay and silica. Clay= effective retaining, gradually releasing water. Forms a crust when dry, reducing evaporation. Higher density and yields in Jerez (avg 70 hL/ha). Light colour reflects light for ripening

Question 5

Powdery Mildew:

Answer 5

Erysiphe necator. Oidium. Fungal disease to all green parts of the vine by covering them with grey-white powder. Doesn’t need damp condition but doesn’t like UV so shady condition good for spread. Chardonnay, Pinot Noir very susceptible. Sulfur, systemic fungicide, canopy management, especially from budbreak to veraison. Inhibits photosynthesis, affects skins, makes berries split. Reduces yield

Question 6

Downy Mildew

Answer 6

Plasmopara viticola. Needs warm 22-30, and damp conditions. Affects young shoots and leaves, oily yellow patches and underside downy cover, hinders growth, make leaves wilt, make vine shut down, berries shrivel. Bordeaux Mixture (copper, lime and sulfur) as fungicide, or systemic fungicide.

Question 7

Botrytis Bunch Rot

Answer 7

Destroys flavour and integrity of fruit. Several microorganisms like fungi and bacteria causes it, Botrytis cinerea is the most familiar. Often begins at flowering, dormant until veraison, then feed on the sugar when berries begin accumulating sugar.

Question 8

Esca

Answer 8

Form of grapevine trunk disease, also called Petri in young vines. Fungal disease caused by spores entering the vine via wounds from pruning. Infects the cordon and trunk, hindering sap flow and nutrient transfer, brown cankers occur. Results in premature replanting and vine death, big economic threat

Question 9

Phylloxera

Answer 9

American root lice attacking Vitis Vinifera rootstocks, need to graft on American rootstock. Doesn’t like sandy soils

Question 10

Weather Hazards

Answer 10

Springfrost
Hailstorms
Drought & Heatwaves

Question 11

Brettanomyces

Answer 11

Baterial yeast causing

Question 12

DIAM

Answer 12

Bouchard Pere et Fils switched over to DIAM closures in 2003, William Fevre in 2004, Hugel in Alsace followed. Diam 5, 10 and 30 for Burgundy usually. 5 has higher permeability than 10 or 30. Made of French cork but no TCA, no premox, Preservation of free SO2, there is also origine by Diam, which is bio-sourced

Question 13

GUALA

Question 14

Name two chemical oxidation processes

Answer 14

1. Oxidation of flavonoid phenols: grape skins seeds and stems, more vigorous pressings result in higher levels of these phenols compared to whole cluster pressing. Oxidation causes the colour change. (SO2 prevents this)
2. Oxidation of ethanol. Oxidized by hydrogen peroxide(from oxidation of phenols) present in the wine, producing acetaldehyde. SO2 also reacts and removes hydrogen peroxide.

Question 15

SO2 level at bottling

Answer 15

William Fevre Chablis: 30mg/l (20% less from 40, since using Diam)

Question 16

What’s the role of SO2

Answer 16

Antioxidant & anti-micorbial

Question 17

Explain relation of pH and SO2

Answer 17

At higher pH levels, more total SO2 is needed to achieve the same amount of free SO2. Meaning more acidic wines can do with less SO2 addition to have the antioxidant and anti-microbial effect. SO2 also works generally better in lower pH. Number example: pH 2.9 (Riesling, Mosel, Saar) = 7.5% molecular SO2 / pH 3.9 (Malvasia Bianca can go up to 3.87) , 0.8% molecular SO2

Question 18

what are thiols

Answer 18

also mercaptans, usually negative aromatic compound in high concentration formed by yeast metabolism during alcoholic fermentation or by yeast reacting with sulfuer in the lees after fermentation. Rotten cabbage, burnt rubber - often sign of reductive winemaking faults. At extremely low concentration, can have positive aromas( grapefruit, passionfruit Sav Blanc and other aromatic whites), gun flint in Chardonnay, powerful coffee aromas with toasted oak staves

Question 19

What are phenolics

Answer 19

A broad group of compounds that contain at least one phenol group. Includes tannins, flavonoids, anthocyanins, etc. – important in wine for color, bitterness, astringency, and aging potential

Question 20

What are flavonoids

Answer 20

Flavonoids are a major group of phenolic compounds naturally found in grapes, especially in the skins, seeds, and stems. They play a key role in the color, taste, mouthfeel, and aging potential of wine.

🍷 Flavonoids by Wine Type:
Red Wines:
High in anthocyanins and tannins, extracted during fermentation with skins.
Rich in flavonoids, especially if made with extended maceration.

White Wines:
Lower flavonoid content due to minimal skin contact.
Still contain flavan-3-ols and flavonols, especially in oxidative or skin-contact styles.

Question 21

What are quinones

Answer 21

🍷 Quinones in Wine:
🔄 Formation:
Formed when phenolic compounds (e.g., catechin, caffeic acid) react with oxygen or enzymes like tyrosinase.
A phenol becomes a quinone through oxidation, either enzymatic or chemical, involving the conversion of –OH groups on the aromatic ring to =O groups.

Common in white wine due to fewer natural antioxidants (e.g., anthocyanins).

⚠️ Reactions:
Quinones are highly reactive and can:

React with aroma compounds (e.g. volatile thiols → aroma loss)

Bind with SO₂, reducing available free SO₂

Initiate browning reactions (especially in white wine)

⏳ Impact:
Contribute to oxidative spoilage, including color browning and aroma degradation

Can also interact with proteins, affecting clarity and stability

Question 22

What are Glutathiones

Answer 22

glutathione, or glutathion, sulfur-containing compound (tripeptide) found in grape juice and an important antioxidant which has been shown to play a significant part in the ageing of wines and in protecting them from premature oxidation. It also has an important role in the formation of some precursors of volatile sulfur compounds and in stabilizing the thiols which characterize the aroma of Sauvignon Blanc and possibly some other white grape varieties.

Glutathione also plays a major role in grape composition and wine quality: higher levels of glutathione lead to higher levels of flavour precursors and lower levels of phenolics.

Question 23

what are terpenes

Answer 23

Linalool, geraniol – contribute floral, citrusy aromas in Muscat, Riesling, Gewürztraminer

Question 24

primary nutrients for grape growth

Answer 24

nitrogen, potassium, phosphorus

Question 25

Summer pruning. Name all 7 techniques

Answer 25

Disbudding, shoot removal, shoot positioning, pinching, shoot trimming, leaf removal, crop thinning/ green harvesting

Question 26

What are Yeast Nutrients

Question 27

What are Oenological tannins

Question 28

Explain Bentonite

Answer 28

Bentonite, so called because it was first discovered in the Fort Benton rock series, is widely used in the new world to ensure protein stability, particularly to remove heat-unstable proteins from white wines, thus taking away the risk of deposits or hazes.

Question 29

Explain Carbon as additive

Question 30

Explain Dimethyl Dicarbonate

Question 31

EU limit for VA

Answer 31

(Expressed as Acetic) 1.2g/l for reds, 1.07g/l for whites and rosés

Question 32

EU Classification for Small / Medium and Large Company

Answer 32

The EU classifies compaies as micro and small (0-9 and 10-49 employees respectively, here considered together and called 'small'), medium (50-249) and big (250+)

Question 33

small and medium size winery by case

Answer 33

According to Wine Business Analytics, a small winery produces between 5,000 and 49,999 cases per year and a medium winery produces between 50,000 and 499,999 cases per year.

Question 34

Size of fine wine market

Answer 34

in a research by Bain & company (2024) the fine wine market accounts for 1.5% of the total by volume but 11% by value

Question 35

Eutypa Dieback

Answer 35

Eutypa Lata is the fungus, grapevine trunk disease, typically affects only a single spur before advancing through the rest of the vine. 'The Dead Arm' Shiraz by D'Arenberg as example. Causes stunted shoots, shriveled fruit, small cupshaped chlorotic leaves

Question 36

Flavescence Dorée

Answer 36

Baterial Disease, "Grapevine Yellows". Primarily found in Southern European wine regions. Delayed, abnormal shoot growth, discolored leaves, berry dehydration. Leafhoppers are primary vector of grapevine yellows, conrol of insects and removal of diseased vines

Question 37

Pierce's Disease

Answer 37

Baterial disease caused by Xylella fastidiosa, preventing transport of water. Vetored by sap-feeding insects like sharpshooters and spittlebugs. More common in California, less in Europe where winters are cold. Infected vines typically die within two to five years but cold winters can delay. No treatment

Question 38

Red Blotch

Answer 38

Virus found in 2011 in California. Lowers wine quality by delaying and preventing ripening. Leaves are infected, sometimes mistaken for leafroll virus

Question 39

Isinglass

Answer 39

isinglass, a particularly pure protein obtained from the bladders of sturgeon and other freshwater fish that has been used for fining wine for centuries. Like gelatin, isinglass reacts with the excess tannins in harsh young red wines. Although expensive and difficult to prepare, isinglass is also occasionally used in the clarification of white wines. However, there is a noticeable trend away from the use of animal-derived products for fining, mainly in the interests of vegetarians and vegans, and isinglass is now rarely used, especially on red wines. If used, it does not need to be declared on the label as it is not present in the final wine.

Question 40

EU Commission guideline for sweetness level (g/L)

Answer 40

Dry 4g/L and 9g/L with total acidity within 2g/L, medium-dry 12g/L, 18g/L with total acidity rule, sweet 45g/L +

Question 41

Trad Meth sugar level

Answer 41

Brut Nature with zero dosage to 3g/L RS, Extra Brut at up to 6g/L RS, Brut with 12g/L RS, Extra Dry with 12-17g/L RS, Sec with 17-32 g?L RS, Demi-Sec with 32-50g/L RS and finally Doux with 50+g/L RS

Question 42

Name of malo bacteria

Answer 42

Oenococcus Oeni

Question 43

Timing of malo (4)

Answer 43

1. pre-alcoholic /reverse MLF (L. Plantarum) 2. Co-inoculation (early 24-48h after yeast) 3. During, late AF 4. Sequential

Question 44

TSO2 levels

Answer 44

The typical range for total sulfur dioxide (TSO₂) in wine varies depending on the style and regulations of the region, but here’s a general breakdown: • Dry white wines: usually 80–150 mg/L (milligrams per liter) • Dry red wines: usually 50–100 mg/L • Sweet wines: can be much higher, often up to 300–400 mg/L (because sugar binds some of the SO₂, requiring more to be effective) These numbers can vary based on the winemaking practices and desired protection against oxidation and spoilage. Legal limits (varies by country and style): • European Union (EU): up to 210 mg/L for dry red wines, 260 mg/L for dry whites, and higher for sweet wines (up to 400 mg/L or more). • USA: generally 350 mg/L for most wines. • Australia/NZ: similar to EU limits. Importantly, free SO₂ (the active antimicrobial and antioxidant fraction) is what really protects wine. It’s usually about 20–50 mg/L in finished wines, though this varies.