Level 4 D1 Chap 14 - Maturation Flashcards
What are the main choices when storing wine before bottling?
Fruity, fresh wines that have limited oxygen exposure are likely to be held in stainless steel and bottled quickly after fermentation
Wine may be matured in bulk in large inert vessels, or barrels that allow slow oxygen exchange
Barrels may be old or new wood
Wine may be help on its lees, and stirred or left.
How does the role of oxygen impact the length of maturation of white wine differently to red wine?
Red wine has anti-oxidative properties from phenolic compounds. Therefore it can typically withstand a longer maturation of 12-24 months.
White wine is typically matured (if at all) for only 6-12 months.
How does the size of a barrel impact maturation?
Water and alcohol impregnate the wood and slowly diffuse out of the barrel sides, to be replaced by ullage. The ullage increases oxidation.
As smaller barrels have a larger surface area to volume ratio, this process is faster compared with larger barrels
What is micro-oxygenation and what are its benefits/risks?
Micro-oxygenation is bubbling oxygen through wine, measured in mg/l per month.
It is much more precise than barrel ageing, and saves money over making barrels.
It is an unproven technique however which has risk as longer term outcomes are unknown, and may provide a great chance of spoilage.
Why is wine matured in cellars?
Cellars are cool, which slows down the effect of oxygenation, and prevents some undesirable reactions that can happen at warmer temperatures.
Cellars also reduce evaporation loss due to humidity
How does an oak barrel’s impact on wine change as the barrels are older and more used?
Oak has extractable compounds, mainly tannins and aroma compounds.
The levels of these in oak typically halve in year 1, and by year 4 will not contribute noticeably.
Permeability to oxygen and evaporation remain unchanged over time.
What are common barrel sizes for maturation?
Barriques 225L
Foudres - large vessel +2,000L
What types of oak are there and what are their key characteristics for wine maturation?
European - higher in tannin American - high in lactone (coconut) Hungarian - tight grain, slow release of compounds Russian Slavonian
How does oak type impact cost?
Manufacturing
American barrels is about half the cost of European as wood can be sawn, not split.
What are the key processes in making a new barrel?
Season the wood for 2-3 years
Saw/split into staves.
Heat to bend (toasting)
What alternatives are there to barrel ageing to achieve oak aromas?
Adding oak chips or staves in a stainless steel or concrete vessel
What forms lees?
Dead/dying autolysed yeast
Bacteria
Grape fragments
Precipitated tannins
What different types of lees settle over time?
Gross lees settles in the first 24 hours after fermentation.
Fine lees is everything after that.
What impact does lees have on wine?
Autolysed yeast release compounds that:
- contribute flavour
- bind with phenolic compounds to reduce colour and soften tannins,
- bind with wood components to reduce astringency and modify wood flavors
- stabilise the wine against haze-causing proteins
- protect from oxygen
- produce sulfur compounds (potentially good in low quantity and bad in high)
- IN WHITES: can add yogurt, dough, biscuit or toasted bread compounds.
Describe racking
Racking is the transfer of wine between vessels, leaving sediment behind.
It can be oxidative, unless inert gas flushing is used.
It can be carried out multiple times, depending on the desired oxygen exposure and lees exposure
