Common Elements In Winemaking And Maturation Flashcards
Bitter oils and tannins are found in which part of the grape?
The seeds
What is the waxy surface covering the grape skin called, and what does it contain?
- The bloom
- Yeast
What is the largest single component of a grape’s pulp?
Water
What are the two most abundant forms of acid found in the grape’s pulp?
1) Tartaric acid
2) Malic acid
What are the 3 sources of tannin within a grape?
- Skin
- Seeds
- Stem
What 3 components do grape skins contain?
- Flavour compounds
- Tannins
- Colour compounds
What are 2 ways to counter oxidation?
1) Use of antioxidants such as sulfur dioxide
2) Taking precautions to oxygen contact to a minimum
Why does picking grapes at night help counter oxidation?
It is cooler - chemical reactions occur more slowly at lower temperatures, so the effect of oxygen contact is reduced
What 2 names are used to call the process of making wine with as little oxygen exposure as possible?
1) Protective winemaking
2) Anaerobic winemaking
Will wines made in a protective style benefit from oxygen contact during maturation?
Rarely, if ever
How would you store and mature wines which had been made in a protective style?
In inert airtight tanks or vats which are kept completely full
What 2 materials are inert maturations vessels made from?
1) Stainless steel
2) Cement lined with epoxy resin
Where would aerobically-matured wines be stored?
Wooden vessels, usually made from oak
Why is oak an ideal storage and maturation material for many wines?
It is watertight but not airtight
What happens with oxidative ageing to the colours of:
1) Red wine
2) White wine
1) Become paler and gain a hint of brown
2) Become deeper and gain a hint of orange
Which has a greater oxidative effect, a small or large oak barrel?
Why?
A small barrel, because they present a proportionately larger surface area of wood to the wine
How long are wines usually kept in barrique for?
Rarely longer than 2 years, as their oxidative effect is relatively strong
How can the effect of oxygen be enhanced whilst using a wooden vessel?
By not filling the container completely
Name 3 wines which are deliberately oxidative in style
- Oloroso Sherry
- Tawny Port
- Rutherglen Muscat
What happens to wine when it gets too much exposure to oxygen?
It can lose much of its fresh fruit flavour and smell stale and vinegary
What two uses does sulfur dioxide have in the winery?
It acts as an antioxidant and an antiseptic
What is strictly controlled by law because it can be toxic?
Upper levels of SO2 in wine
Why is it preferable to keep SO2 levels as low as possible?
High levels can make the wine seem harsh and lacking in fruit
What does it mean when SO2 becomes ‘bound’?
It loses the ability to have any further protective effect against oxygen
Why must levels of SO2 be constantly monitored and replenished?
It becomes bound as it protects the grape juice and wine against oxygen, so needs topping up
Why is SO2 used to kill off the many strains of yeast and bacteria which are found in wines?
They can cause unwanted flavours in the wines
Why doesn’t SO2 kill off the principal yeast involved in fermentation?
The levels used are toxic to other species, but these commercial yeasts are tolerant to those levels
Of what are the vast majority of wooden vessels made?
Oak
What are the 2 advantages of using oak for maturation?
1) They allow a small amount of oxidation, developing tertiary aromas
2) The wine can extract tannin and flavours from the oak
What do oak tannins add to red and white wines?
3 points
1) Structure
2) Textural complexity
3) Aromas such as toast, vanilla, smoke and cloves
Why is hygiene an issue with oak vessels?
It is difficult to keep them completely free of yeasts, bacteria and moulds; tainted wood can ruin a wine.
What are the 4 factors to consider when choosing an oak vessel for maturation?
1) Species and origin of the oak
2) Size
3) Production method of the barrel
4) Age
From which 2 continents does the majority of the oak used in winery vessels originate?
Europe and North America
Which 3 European countries produce the most oak for barrels?
- France
- Hungary
- Russia
What size is a barrique?
225 litres
What size is a pièce?
228 litres
How large can the biggest oak vessels be?
In excess of 2000 litres
Why do smaller oak vessels have a much greater effect on the wine than larger ones?
Because in smaller vessels, much more of the wine is in contact with the surface area of the barrel