Human factors in the winery Flashcards
Roles of the oxygen2
Oxygen is a gas that can react with grape/juice during wine making and maturation
Roles of SO2 (solfure dioxide)
(i) It’s an antioxidant and antiseptic almost indispensable in the winery
(ii) restricted by law because it can be toxic
Types of winery vessels
(i) Oak
(ii) Steinless stell
(iii) Concrete vessels
Alcoholic fermentation definition
Conversion of sugar into alcohol and CO2 through the action of the yeast (+ flavour and temperature)
Explain Malolactic fermentation (MFL)
(i) it takes place one the alcoholic fermentation has finished
(ii) carried out by lactic acid bacteria that convert tart malic grape acid into lactic acids
(iii) MFL reduces the acidity and create buttery flavours
(iv) smooth the acidity
(v) Chardonnay
Types of adjustments
(i) Enrichments - sugar and alcohol
(ii) Acidification - addition of tartaric acid in powder
(iii) Deacidification - addition of alkali
What happens in case of wine maturated aerobically?
(i) in term of color: red wines become paler and white wines become deeper in colour
(ii) the amount of oxydation depends on size of the vessels and time
- -> 225l barrique have a greater oxidative effect than larger vessel, due to larger surface of wine exposed to wood (no more than 2 years)
- –> Oxidative effect enahanced by containers not completely full. This technique is used for fortified wines (ie. Oloroso, Sherry, Tawny Port and Rutherglen Muscat). This develop tertiary character as caramel, toffee and nuts
(iii) Over exposure can be damaging as wine lose its freshness and fruit flavour
(iv) Bacteria with oxygen can turn wine into vinegar
Effects of SO2
(i) Antioxidant - protects grape juice and wine from oxidation
(ii) Antiseptic - against bacteria that can cause unwanted flavours in the wine
What is the most common yeast?
Saccharomyces cerevisiae due to his tolerance to SO2 and alcohol
Thnings to know about alcholic fermentation
(i) It won’t start if the temperature is below 5°
(ii) it should continue naturally until all the sugar is consumed
(iii) it can stop before if the yeast run out of nutrients or the temperature is above 35°
Types of yeast
(i) ambient yeast strains - complex flavour but hard to control
(ii) cultured yeast - limited complexity of the wine but easy to control during wine making
Red wine fermentation temperature
20° - 32°
White wine fermentation temperature
12° - 22°
High volume inexpensive white wines (=’dry and fruity)
Pinot grigio, Chardonnay
High volume inexpensive red wines
Cabernet Sauvignon, Merlot, Syrah/Shiraz, Grenache/Garnacha
Which one of the following is used to protect wine from oxidation?
- Sulfur Dioxide
- Kieselguhr
- Acetic Acid
- Hot bottling
1.
Techniques of clarification
(i) Sedimentation
(ii) Fining
(iii) Filtration
Explain what carbonic maceration is and the style of wine it produces
x
List 4 methods of concentrating the grapes sugars in the production of sweet wines.
y
Describe the characteristics of the Riesling grape
z
Which of the following can be added to de-acidify a wine?
a) Alkali
b) RCGM
c) SO2
a)
Which of the following is a type of must enrichment to increase the potential alcohol of a light wine?
a) Chaptalization
b) Süssreserve
c) Adding grape spirit
?
Which of the following wine styles would be deliberately oxidized in partially-filled oak?
a) New Zealand Sauvignon Blanc
b) Burgundian Pinot Noir
c) Oloroso Sherry
?
Which is used as both as an antiseptic and antioxidant in winemaking?
a) CO2
b) H2O
c) SO2
c)
What is meant by racking?
a) Wine is pumped into a different vessel leaving the sediment behind
b) Wine ageing in oak barrels are stored on warehouse racks
c) Wine is left on its lees and stirred regularly
a)
When oxidation can be enhanced?
Fortified wines: Oloroso Sherry, Tawny Port and Rutherglen Muscat
What is sedimentation?
(i) Technique of clarification where the wine is pumped into a different vessel (racking)
(ii) It can be accelerated with centrifuge
What is fining?
Technique of clarification where particles are removed before bottling adding a fining agent. This ensure wine stability
What is filtration?
Technique of clarification where the wine is passed through a filter: (i) depth filtration to remove gross lees (ii) surface filtration expensive, final treatment before bottling
When a wine can be considered stable?
When it changes in a slow predictable manner
What are tartrades?
Crystals of tartaric acid, harmless and flavourless but worsen the appearance of the wine. Removed with filtration
Types of closures
(i) Cork
(ii) Syntetic corks
(iii) Screw cap
What cause cork taint?
It’s caused by a chemical called TCA, present in some corks that gives the wine a moudly , carboard-like aroma
Where screw caps are typical?
Australia and New Zeland
Aromatic grape varieties
Sauvignon blanc, Riesling, Muscat, Gewurztraminer, Torrontés
Sweet winemaking types:
(i) Stop fermentation [fortified wines]
(ii) Add sugar [Germany]
(iii) Noble rot [Sauternes]
(iv) Dry grapes on the vine [Petit Manseng, Juranson -Passerillage, Late Harvest)
(v) Dry grapes after picking [Passito wines in IT, Regiocoto della Valpollicella DOCG]
(vi) Freeze grape [Ice wines in Canada, Eiswein in Germany]
What is Passerillage?
Dry grapes on the vine after they reached full sugar ripeness (e.g Petit Manseng, Jurancon]
Rosé winemaking types:
(i) Direct pressing
(ii) Short maceration
(iii) Blending
What is Sussreverve?
Unfermented grap juice added to dry wines when they are ready to be bottled to create sweet wines [Germany]
What is RCGM
Rectified Concentrated Grape Must
Which sweet wines are made with noble rot (botrytis cinerea)
Sauternes, Tokaji, Beerenauslesen and Trockenbeernauslesen
Cap management techniques
(i) punching down - punch the cap
(ii) pumping over - pump fermeting juice from the bottom
(iii) rack and return - another vessel
(iv) rotary fermenters - horizontal tank
Carbonic maceration
Uncrashed bunches into vats filled with CO2
Semi-carbonic maceration
The fermentation of the yeast produce CO2
Types of bunches fermentation:
(i) Carbonic maceration
(ii) Semi-carbonic maceration
(iii) Whole bunched with crashed fruit
Which wine is notable for Semi-carbonic fermentation?
Pinot noir
Styles of Merlot
(i) International style - harvest as late as possible
(ii) Bordeaux style - harvest earlier to a medium body wine
What can be blanded with Carbernet Sauvignon?
(i) Merlot»_space; Bordeaux
(ii) Sangiovese»_space; IT
(iii) Tempranillo»_space; ES
Fermentation temperature for Cabernet Sauvignon
26°-30°
Oak months for Cabernet Sauvignon/Merlot
12-18
Oak months for Pinot noir
12-24
