Maturation Flashcards
What are the main differences between European and American Oak as it is used to mature wine?
Both contribute significant levels of vanillin however American Oak contains much higher levels of lactones: which give coconut aromas. American oak tends also to impart greater intensity of aromas/flavors that European oak. However European Oak tends to impart more tannin.
French oak vessels are more expensive to buy than American oak due to greater production costs being high for French than American.
What are some examples of other types of wood apart from oak used in wine maturation?
Chestnut, Cherry and Acacia.
What is the typical range of time wood is seasoned for? Why is the wood seasoned?
2-3 Years. It lowers humidity levels in the wood, reduces bitter flavors and increases some aroma compounds, such as those that give flavors of cloves.
How are oak barrels produced?
European oak is split and american oak is sawn to create staves. These are then heated and bent into the shape of a barrel. Temperature and length of heat exposure is referred to as the level of toasting. typically categroies are: light-, medium- or heavy-toasted.
What notes does toasting contribute to wine?
Notes of spice, caramel, roasted nuts, char and smoke.
Why is maturation in wood so costly for the production of wine?
- Expensive to buy
- Small barrels do not hold much volume which means hundreds may be needed (more cost to purchase and to store)
- Monitoring the wine in each separate barrel and performing wine making operations like lees-stirring or racking is labor intensive.
- Meticulous cleaning and sanitation is needed as spoilage organisms live in wood
- Barrel maturation is a slow process- (ie typically 102 years) which means return on investment is slow. (Selling wine en primeur can address this)
What are some alternatives to barrels that can be used to impart flavors of oak to a wine and what are their advantages?
Oak Chips and Oak staves. Can be used within stainless steel or concrete vessels or can float in the wine so they are less labor intensive, cheaper and their large surface area means they affect the wine quickly. (Micro-Oxygenation can be used alongside oak alternatives to mimic the gentle oxidation of barrel maturation).
What are lees?
Lees is the sediment that settles at the bottom of a wine vessel- made up of dead yeast, dying yest and bacteria, grape fragments, precipitated tannins, nutrients and other compounds.
What are gross lees?
The sediment that forms quickly after fermentation (within 24 hrs) made of larger, heavier particles.
How does lees contact effect the wine being produced?
- Through autolysis- the slow death of yeast- compounds that contribute flavors, body and texture to the wine.
- Autolytic compounds bind with phenolic compounds in the grapes- reducing color and softening tannins.
- Autolytic compounds from lees also bind with wood components such as wood tannins and flavors- reducing astringency and modifying flavors of the wood
What precise aromas/flavors do lees contribute to wine?
Hard to define as compounds released from yeast react with aroma compounds already in the wine- so the interactions are complex. In white wine the effects are more significant/noticeable and descriptor include yoghurt, dough, biscuit or toasted bread.
How can lees ageing assist white wine?
- Helps the stabilization of white wine against unstable proteins that can cause hazes.
- Can help protect the wine from oxygen, helping to maintain a slow controlled oxidation during maturation and lowering the need to use SO2 during this time.
When can lees ageing impede or negatively effect wine?
If the layer of lees becomes too thick and may contribute un-plesant aromas, such as the smell of rotten eggs (fault called reduction)
What does lees ageing add to the cost of wine production?
1) May increase the time wine is stored at the winery before release
2) Wine aged on lees (especially gross less) need to be monitored regularly and may be stirred manually to agitate the layer of lees which adds to labor costs
3) If matured in barrel there is unlikely to be significant extra cost on top of what there is for barrel maturation however less stirring may be costly in terms of labor (for cellar door workers to do batonnage)
