Maturation Flashcards
Blending
Refers to mixing two or more batches of wine
Can take place at any tie during the winemaking process, but is most often carried out jus prior to finishing and packaging
Blending may involve combining wines from (6):
- Different grape varieties
- Different locations (vineyards, regions, countries)
- Different grape growers that sell grapes, must or wine
- Different vintages
- Wine that have been treated differently in the winery
- Wines that have been treated equally in the winery but are in different vessels for logistical reasons
What can and cannot be blended often depend on local legislation. For example EU PDO labeled wines, grapes must come 100% from the defined geographical area. For example Brunello di Montalcino DOCG must made from 100% Sangiovese
There are several key reasons for blending wine (7)
Balance
Consistency
Style
Complexity
Mimimise faults
Volume
Price
Blending - Balance
Blending may help to increase or moderate the level of certain characteristics of the wine to produce a wine that is better balance, and in this way enhance quality
Example:
A batch of wine from a warmer vineyard or that has been packed late may be blended with a batch of wine from a cooler vineyard or that has been picked early to fine. tune acidity levels
Also, the use of different varieties is common to enhance the balance of the wine. Well known blending partners are Merlot and Cabernet Sauvignon
Merlot ads body and ripe fruit to a blend with Cabernet Sauvignon, which, when not fully ripe, can be too tannic on its own
Blending - Consistency
Significant variation among bottles in a single vintages is seen as a fault
Bleeding can be necessary to ensure a certain volume of a consistent product
In some wine styles consistency is needed across vintages. Including most styles of sherry and non-vintage sparkling wine, but also many inexpensive wines where the consumer may not expect nor accept significant vintage variation
Blending - Style
Blending is often fundamental in reaching a desired style
Even where vintage variation may be accepted and promoted, winemakers often make their wines to a certain ‘house style’ or want to create wines of certain quality levels within their range (first wine, second wine)
Also, some rose wines are made by blending red and white wine, this method allows very precise control over colour and flavour profile
Blending - Complexity
Blending two or more parcels of wine may lead to a greater range of flavours, and in this way enhance the complexity and therefore the quality of the final wine
Blending - Minimise faults
If a wine in one barrel is showing significant VA, that wine may be sterile-filtered to remove acitic acid bacteria and then blended into a larger volume of un-faulty wine to lower the concentration and sensory perception of the VA
Blending - Volume
In areas with small vineyard holdings, winemakers are likely to need to blend the wines from different vineyards to produce viable volumes of certain wines
Also, in poor vintages or in case where the producer has minimal vineyard holdings, grapes, must or wine may need to be bought in to reach certain volumes and satisfy the needs of their costumers
Blending - Price
Many inexpensive or mid-priced wines will be made to sold profitably at a certain price point
In this case, blending different parcels of wine can help to create a certain style and quality
For example, Chardonnay is sometimes blended with Trebbiano and Semillon. The later two grapes are generally cheaper to buy than Chardonnay, keeping the price point of the win low
Because Chardonnay is one of the most recognized varieties internationally, the inclusion of this grape in the blend helps the wine to sell
Lees
Describes the sediment that settles at the bottom of a wine vessel.
Made up of: Dead yeast and dying yeast Bacteria Grape fragments Precipitated tannins Nutrients and other insoluble compounds
Gross lees
The sediment that forms quickly after fermentation, made up of the larger and heavier particles
Fine lees
The sediment that contains smaller particles and settles more slowly
Autolysis
After fermentation, yeast cells will slowly die and break down.
It releases compounds that contributes flavours, body and texture to the wine.
Some of these compounds bind with phenolic compounds in the grape, reducing colour and softening tannins
They can also bind with wood tannins and wood flavour, reducing astringency and modify flavours from the wood
The reaction of lees compounds and aroma compounds
In white wines the effects of lees are generally more significant, given aromas like;
Yoghurt
Dough
Biscuit
Toasty
These can be very subtle
Lees aging and stabilization of the wine
Lees aging helps in stabilization of the wine against unstable proteins that can cause hazes
Lees aging and protection from oxygen
Lees helps to protect the wine form oxygen, helping to maintain a slow, controlled oxidation during maturation and lowering the need of so2 during this stage
However, if the layer becomes too thick, particularly a problem for gross lees, it can produce volatile, reductive sulfur compounds. In some levels this can give a certain complexity (struck match, smoke) but if not controlled this can give the wine unpleasant aromas like the smell of rotten eggs, which is a fault (reduction)
Lees aging and nutrients
Lees provides nutrients for microbes and therefore can assist the growth of lactic acid bacteria for Malo
But, also encourage the development of spoilage microbes such as Brettanomyces
Impact on the cost of lees aging
Lees aging increase the time the wine is stored at the winery before release, increasing the final cost of the wine
Also, wines aged on the lees need to be monitored regularly and may be stirred, this requires labour cost
inexpensive vs more premium wines that are aged longer and sold at higher prices
The role of oxygen in wood maturation
Wooden vessels permit a slow exposure to oxygen during the wines maturation
A newly-made vessel also contains various extractable compounds, including tannins and aromas, which can have a significant influence on the final wine
The level and compounds extracted from wooden vessels depend on the following features:
- Age of the vessel
- Size of the vessel
- Type of wood
- Production of the vessel
Age of the vessel
Each time a wooden vessel is used, the amount of extraction decreases because fewer extractable compounds remain (50% loss during first year of use)
By the time its on its fourth usage, it will contribute very little at all but still allows the ingress of oxygen
Flavours of new oak may be to dominant for many wine styles, therefore pre used barrels may be used or if new oak is used, it’s typically a part of the wine that is blended with wine stored in pre-used barrels
Size of the vessel
Small vessel (barriques 225l) hold a relatively small volume of liquid compared to the surface area of the vessel
Meaning, any extraction from the wood and exposure to oxygen is greater in small vessels than in large vessels, such as foudres
Type of wood
Oak is the most common type of wood, its easily shaped, watertight and prized for its positive effects on the aroma/flavour structure of the wine
Most oak vessels are made of European oak. Typically French, but also Hungarian, Russian or Slovenian, or American oak
Although oak is by far the most commonly used type of wood, chestnut, cherry and acacia are also occasionally used
The differences between European and American oak
Both types of oak have significant levels of vanillin, contributes vanilla
American oak has been found to contain much higher levels of lactones, which give aromas of coconut and in general tends to impart greater intensity of aromas and flavour than European oak, which is often more subtle.
By contrast, European oak tends to impart more tannin and European oak is more expensive 600-1200
American oak barrels tend to range from 300-600, they ability to saw American oak means more vessels can be made from the same amount of oak, and it also grows quicker than European oak
Russian and Hungarian oak
Grows in continental climates, and tend to grow slowly and therefore has the tightest grains. Which slows down the extraction of compounds compared to coarser grained wood.
Example:
Hungarian, tight grain, is gaining popularity in New York State as an option that allows very gradual extraction of oak aroma and tannins for their red wines (medium in alcohol, tannins and flavour) so they are not dominated by oak derived characteristics
Production of the vessel:
Seasoning
Heating
Housestyle
The way the vessel is made influence will have an impact on how it will affect the wine
Before constructed, the wood needs to be seasoned. This typically takes place outside and last 2-3 years. It lowers the humidity levels in wood, reduce bitter flavours and increases aroma compounds (cloves)
The process involves heating the stave to bent them into shape, the heating process also transforms the tannins and aroma compounds in the oak
The temperature and length of heat exposure is referred to as the level of toasting (light, medium or heavy toasted) and contributes aromas of spice, caramel, roasted nuts, char and smoke. The heavier toasted, the more pronounced these aromas become. Although this also depends on the time the wine spend in the vessel and the size of the vessel and type of wood used
Many cooperages produce their vessels to a certain house style
Barrel maturation
Expensive mid-priced, primium or super premium wines
- Expensive to buy
- Small barrels do not hold much liquid, so many of these may be necessary
- Monitoring the wine in each barrel (stirring/racking) is labour intensive
- Spoilage microbes (brett) live in the wood, which requires cleaning and sanitation which adds to the labour costs
Finally, its a slow process and not uncommon to store the wine for a min 1-2 year, or even longer therefore ROI is low
Oak chips and staves
Cheaper alternative to barrel maturation for inexpensive and mid-priced wines if oak flavours are desired
For both options you can buy different species of wood and different seasoning and toasting levels
Some winemakers use micro-oxygenation alongside oak alternatives to replicate the gentle oxidation of barrel maturation as this helps to integrate the oak flavours
The impact of oxygen on aromas in the wine during maturation
Oxidation leads to reduction in many primary aromas and development of tertiary aromas (dry fruit, nuts).
If the wine develops pleasant tertiary aromas, and a structure for extended aging, this enhance the quality of the wine.
If primary aromas fade, and not replaced by positive tertiary aromas the quality of the wine is lowered
The impact of oxygen on the colour of the wine during maturation
Oxidation can influence the colour of wine, white wines become darker (gold, brown)
A young red wine exposed to oxygen can result in greater colour stability and intensity. Anthocyanins bind with tannins, which protects antocyanins from being absorb by yeast lees or bleached by so2 additions
Particularly important for light colored red wines, like Pinot Noir
The role of oxygen during maturation
Oxidation reactions lead to a number of changes and phenolic compounds in wine, influencing style and quality
Styles of wine where a high level of oxidation is desired
Oloroso Sherry, the oxidation causes the brown colour of the wine and lack of fresh fruit on the palate which is replaced by dried fruit and nutty aromas
In this case, the wine is stored for a number foyers in barrels that are not filled to the top, allowing oxygen within the headspace of the vessel (ullage)
The speed of oxidation in wine
is influenced by the amount of oxygen exposure, compounds in the wine and temperature
Wine that are exposed fully to air (oxygen) will general oxides quicker than when oxygen exposure is more gradual
Red wines can withstand a higher level of oxygen exposure before any signs of oxidation are apparent, due to they higher content of anti oxidative phenolics (tannins)
Temperature increases the speed of oxidation reactions
Wooden vessels and oxygen
Traditional, still commonly used method of gaining a slow and gradual exposure to oxygen
Some oxygen is released from the pores in the vessel within the first month that the wine is in the vessel, a very small amount of oxygen passes through the gaps between the staves and the bung hole
The time when the wine is most exposed to oxygen during maturation is when the wine is transferred, by racking, lees stirring or topping up (bung removed)
Explain the evaporation of wine during maturation in barrel
Some wine is generally lost during maturation in wood
Water and alcohol in liquid form impregnate the wood, within the wood water and alcohol turn to vapour (evaporate) and diffuse. This leads to a gradual concentration of the other components in the wine
Small vessels have larger surface area to volume ratio, increasing the rate at which wine is lost. Meaning, these barrels frequently need to be topped up with wine to keep them full (avoiding ullage and excessive oxidation). The frequent topping up leads to more oxygen exposure in these vessels than in much larger vessels as the bung is removed more often
Micro oxygenation
A cheaper alternative to the affect of oxidation when matured in wood
Involves bubbling oxygen through wine, typically dosed in until of mg/L per month
Generally carried out in stainless steel tanks for a number of months post alcoholic fermentation
Generally used on inexpensive and mid-priced wines, although a growing number of wineries producing premium wines are using this technique
Its thought to increase colour stability and intensity, soften tannins, improve texture and reduce the presence of any unripe, herbaceous flavours
Rate of oxygen exposure can be controlled much more tightly than it could be in a barrel
Care must been taken, increasing oxygen levels can provide a favorable environment for spoilage microbes (acetic acid bacteria and Brett)
