Chapter 7 - Common Elements in Winemaking Flashcards
Name the parts of the grape
Skin - high concentration of flavour compounds. Also contains tannins and colour compounds
Seeds and stems - contain tannins and bitter oils
Bloom - the waxy surface that covers the skin
Pulp - contains water, sugar and acids (mostly tartaric, a bit malic)
Tannins
What is the chemical process of oxygen reacting with wine reffered to as?
Oxidation
What flavours does oxidation take away from wine?
Primary fruit characteristics
What anti-oxidant is often used?
Sulfur Dioxide
What are some techniques to counter the effects of oxygen in winemaking?
- harvest at night when it is cooler
- keept the grapes chilled as long as possible during and after harvest
- keep the grapes and juice away from oxigen with airtight equipment
Why do lower temperatures help against oxidation?
Chemical processes go slower in lowe temperatures
What gasses are used to keep machinery airtight?
Nitrogen and Carbon Dioxide
What is winemaking with the least amount of oxigen referred to as?
Anaerobic winemaking
Can you mature wines that have been made anaerobicly in oak vessels
No, wines made in that way don’t benefit from any contact with oxigen during maturation
What airtight maturing vessels are there?
- stainless steel
- cement lined with epoxy
What can contact with very small amounts of oxygen during ripening do to wines?
- soften tannins in red wines
- give complexity to flavours: fruit will fade into teriary characters like earth or leather
- colour changes. Red becomes paler and can turn brown, white becomes deeper in colour and becomes a bit orange
Why are wines rarely kept more than 2 years in barriques?
Because of its small size (225 liters), the relative surface touching the oak (and thus oxigen) is very big compared to larger vessels
Why would barrels not fully be topped up? Examples
For fortified wines that have a deliberate oxidative style this is a technique used to create nutty, caramel and toffee flavours.
Olorosso, Tawny Port and Rutherglen Muscat
What is the risk of too much oxigen exposure during ageing?
Too much loss of fresh fruit flavours and stale smell
What is SO2 and what is it used as?
Sulfur Dioxide
- antioxidant
- antiseptic
Why is the use of SO2 restricted?
It can be toxic (though the concentration in wine is lower than dried fruit)
It can cause allergic reactions
What is a ‘bound’?
SO2 when it reacts with O2. It loses its protective ability and becomes a ‘bound’
What does SO2 do, other than protect against oxigen?
It kills off bacteria and yeasts (except for the one that does the alcoholic fermentation)
What other use, aside from micro oxidation, do oak vessels have?
Adding tannin (and thus structure) Adding flavour (like vanilla, toast, smoke and cloves)
What are 4 important factors in choosing the type of oak vessel
- species and origin. Oak from different species or origins can have different characteristics (flavour etc)
- size. Small vessels have more impact than big vessels (due to relative surface contact
- age. The amount of flavour a barrel gives to the wine deminishes with every useage
- production. For instance toasting, which gives distinct flavours to the wine
What is a piece, and what is a barrique?
Piece is an oak barrel of 228 liters
Barrique is 225 liters
What are the 2 main origins of oak vessels?
American Oak and European (French, Hungarian, Russian)
After how many times do oak vessels lose most of their flavour?
After 4 uses
What are other ways than oak barrels to get the aroma’s and tannins in the wine?
Chips or staves
What are 2 ways temperature be controlled in stainless steel vessels?
Sleeves on the outside
Coils on the inside
Why do some wine makers prefer concrete vessels?
The thick shells help to regulate temperature
Why should damaging the seeds be avoided during crushing?
It releases bitter and astringent oils an tannin
When is pressing done?
In white wines before fermentation, in red wines usually after fermentation
What is free run juice?
The juice that comes from crushing, when the skin is lightly broke
What does a traditional (basket) press look like?
It is vertical, with a plate that is raised or lowered by using a screw or lever. Still used in Champagne
How does a pneumatic press work?
With an inflateable tube within a horizontal cylinder, sometimes built within a closed stainless steel tank to minimize contact with oxygen