Ch 14 Maturation Options Flashcards
Maturation
How are wines that are made protectively handled after ferm/MLC?
○ Will continue to be protected from o2 in airtight vessels (s/s) and protected with SO2/inert gas
○ Usually finished/packaged shortly after ferm
○ Some winemakers only bottle when order is placed -> bulk storage (see adv/disadv in ch 15)
Maturation
What are the major components of the maturation phase that impact the QSP of the wine?
○ O2/oxidation
○ New wood
○ Yeast lees
○ Blending
Maturation
What components does O2 impact during mat that impact QSP?
- Aroma compounds
- color compounds
- phenolic compounds
Maturation
What impact does O2 have on aroma compounds?
How does it impact quality of wine?
○ Oxidation generally leads to gradual reduction in primary aromas and development of tertiary ex dried fruit, nuts
○ Enhance wine quality when the primary aromas develop into good tertiary and wine has good aging structure
○ Reduce quality when primary aromas fade and not replaced by positive tertiary
Maturation
What impact does oxidation have on color - white and younger/older reds?
○ Whites - become darker, golden then brown
○ Young reds - improved color stability and intensity -> anthos bind with tannins -> protects anthos from being bleached by SO2 or absorbed by lees
§ Esp important for light colored reds - PN
○ Older reds - after longer O2 exposure, reds become paler and browner
Maturation
What impact does oxidation have on tannins?
○ Softens them, which may improve quality
○ Not well understood
Maturation
What are main factors impacting speed of oxidation during maturation?
○ Amt of O2 exposure, compounds in the wine and temp
○ Wines fully exposed to air oxidize faster
○ Warmer temps also cause faster oxidation
Maturation
Do reds or whites tolerate O2 exposure better and why?
What is the implication?
○ Reds can tolerate more O2 exposure than whites before signs of oxi are apparent -> higher content of anti-oxidant phenolic compounds
○ This is why reds are often matured longer than whites: reds 12-24mos before bottling; whites 6-12mos
Maturation
How do wooden vessels relate to oxidation?
How does it happen - 2 parts of the process?
How does vessel size impact?
-
Slow, gradual exposure to air
§ Mat wine in small wood vessels most common way to get slow, gradual exposure to O2
§ O2 in wood pores released when vessel first filled
§ Small amt of O2 continues to pass thru gaps bet staves and via bung hole
§ Wine is most exposed to O2 during times it is transferred - racking, lees stirring, topping (bung removed)2. **Evaporation** leads to gradual concentration of other wine components § Water and alc impregnate wood -> within staves, they turn into vapor and are released (along the concentration gradient) § Smaller barrels have faster oxi □ large surface area to vol ratio -> faster evap -> needs more frequent topping up = more O2 exposure vs larger vessels □ Amt of O2 that enters is greater relative to volume in small barrels
Maturation
What is micro-oxygenation?
Why do it and how is it done?
What wine prices is it used for?
○ micro-oxygenation is cheaper alternative to barrel maturation which is expensive
○ Bubble O2 thru wine
○ Doses of O2 expressed in mg/L
○ Usually done in s/s for a number of months post ferm
○ Initially done for inexp and mid-price wines, now also more common with prem/super
prem
Maturation
What impact/benefit does micro-oxygenation have?
What are the considerations?
○ Impact - Increase color stability and intensity, soften tannins, improve texture, remove unripe, herbaceous flavors
○ Benefits - delivers effects of gentle O2 exposure faster, much more controllable, if used with oak alternatives, can help integrate oak influence
○ Considerations - exposure to O2 inc risk of spoilage orgs - acetic acid and brett; new technique lacking detailed research on impact across varieties
Maturation
How does temperature impact oxidation and why?
What are storage temps for whites and reds?
○ Temp impacts speed of aging as well as affecting what chem reactions occur and how quickly they occur
○ Wines usually matured at stable, cool temps to slow rate of oxi and prevent spoilage orgs -> cool temps give slower mat than warm
○ Whites - usually stored at 8-12°C; Reds - stored at 12-16°C -> less vulnerable to oxi
○ Warm temps speed up aging, and also tend to cause reactions that are not desirable in wine
Maturation
How does humidity impact oxidation?
Implications?
○ Low humidity (and warm temps) inc rate of evaporation ->
§ Reduces vol of wine avail for sale, impact quality via more freq top-up (inc O2 exposure) and inc labor cost
○ Humidity <70% -> water is lost faster than alc = over time higher alc concentration which can be undesirable
○ Cool temps and constant humidity is key -> modern cellars have controls; why cellars were underground historically
Maturation
What 5 overall factors related to wood vessels impact the amt and level of compounds extracted from wood?
- Age
- Size
- Type of wood
- Production method
- Length of time in wood
Maturation
How does vessel age affect amt and level of compounds extracted from wood?
○ New wood has extractable compounds
○ Each time barrel is used, amt of extraction decreases - loses ~50% new oak flavors after first use
○ By 4th use, adds little - still allows O2 in
○ When new oak Is used, usually as a proportion of a blend with wine stored in neutral barrels
Maturation
How does vessel size affect amt and level of compounds extracted from wood?
What is a barrique?
Barrique - 225L wood vessel
Smaller vessels hold small volume rel to wood surface area -> more extraction and O2 contact vs larger barrel
Maturation
What 2 factors related to type of wood affect amt and level of compounds extracted from wood (2)?
○ Where it is from
○ Tightness of grain
Maturation
What is most common type of wood used and why?
What other types used?
Oak
○ Easily shaped into barrel and makes watertight containers
○ Positive aroma/flavor and structure impacts
○ Different species of oak have different attributes, as do same species grown in diff places
Other types - chestnut, cherry, acacia
Maturation
What are most common types of oak?
What are commonalities and differences?
○ European - usually French, but also Hungarian, Russian, Slovenian - and American oak
○ Different species
○ Both have high levels of vanillin
○ Key differences
- American has much higher levels of lactones - coconut aromas; tends to
impart greater aroma/flavor intensity vs Euro oak
- Euro - impart more tannin, but tends to be subtler on aromas/flavor
Maturation
How does gain tightness impact the wine and why?
○ Tighter grain -> tree grew more slowly = tend to be from continental climates (Russian, Hungary)
○ Tight grain slows down extraction of compounds vs coarser wood, and alters what is extracted
Maturation
What are economic considerations for type of wood?
How much do American vs French barrels cost and why one costs more?
○ Production process for euro oak more expensive
○ American barrels - cost €300-600; French € 600-1200
○ Euro oak must be split to make staves, American can be sawed = more vessels can be made from American oak
○ American oak grows significantly faster
Maturation
What is general barrel production process?
How does production of the barrel impact amt and level of compounds extracted from wood?
Before production step and during production step
○ Before vessel is made, wood needs to be seasoned usually outdoors and takes 2-3 yrs -> lowers humidity level in the wood = reduces bitter flavors and increases aroma compounds e.g. cloves
○ Production process - heat staves so they can bent -> heating transforms tannins and aroma compounds
○ Toast level - the temp and amt of time of heat exposure
○ Categories - light, med, heavy toast
○ Toasting adds notes of spice, caramel, roasted nuts, char and smoke -> more pronounced at higher toast levels
○ Many cooperages have “house style” -> common for winemakers to use barrels from a number of coopers for blending options
Maturation
How does length of maturation in wood impact amt and level of compounds extracted from wood?
What factors influence?
○ In general, longer = more extraction and more O2 exposure
○ Rate of extraction/impact not constant -> longer aging can mean greater diversity of compounds extracted
○ Infl - size, type of wood, age of wood, cellar environ
Maturation
Why is barrel aging more expensive?
What price range of wines typically do barrel aging?
○ Normally mid- and premium priced wines
○ Barrels expensive to buy and small barrels don’t hold much volume -> have to buy a lot
○ Monitoring wine in each barrel labor intensive
○ Cleaning is critical to avoid spoilage orgs
○ Barrel mat is slow process - takes 1-2 yrs or more -> ROI is slow
Maturation
What are oak alternatives?
What priced wines use?
How different than barrels?
○ Oak chips - put in permeable sack
○ Oak staves - can go into s/s and concrete or float
○ Can buy diff species and toast levels
○ Much cheaper and can be added to larger tanks -> less labor intensive and can have quicker impact due to larger surface area
○ Some winemakers use micro-oxygenation at the same time to better integrate oak flavors
○ Hard to define diff vs barrels - depends on source, size and toasting of wood and if micro-oxi is used
○ Inexpensive, mid-priced wineries
Maturation
What are lees?
What are gross vs fine lees?
Lees:
○ Sediment that settles to bottom of wine vessel
○ Includes dead yeast cells, dying yeast and bacteria, grape fragments, precipitated tannins,
nutrients and other insoluble compounds
Gross Lees: ○ Sediment that forms quickly after end of ferm w/in 24hrs ○ Larger, heavier particles
Fine lees:
○ Smaller particles that settle more slowly
Maturation
What is racking?
How is it done?
What are considerations (red vs white)?
○ Process of transferring wine from one vessel to another with goal of removing sediment
○ Can be gross lees, fine lees or other solids
○ Wine removed from orig vessel thru valve near bottom (above top of sediment) and pumped or poured into new, clean vessel
○ Considerations - can be oxidative process
§ Reds - some winemakers deliberately splash to inc oxi
§ Whites/fruity wines - can also protect -> use pressure from inert gas to push wine thru hose to new vessel which has also been flushed with inert gas
○ Can be done once or several times during mat process
Maturation
How does racking relate to lees?
○ First racking removes gross lees
○ Further racking help manage level of lees remaining
Maturation
What are the 4 positive benefits of lees aging?
What are considerations/possible negatives?
Benefits
1. Autolysis flavors
2. Modification of flavors and tannins
3. Stabilization (white wine hazing)
4. Protection from O2 (need less SO2)
Considerations:
1. thickness of lees - too thick create reductive sulfur (rotten eggs)
2. Nutrients for lactic acid bacteria - can help MLC but also enable Brett
Maturation
What is autolysis?
What impact on wine and how?
○ Process of yeast cells dying very slowly and breaking down after ferm -> release compounds that contribute flavor, body and texture to the wine
Impacts: ○ **Bind w/ phenolics -> reduce color and soften tannins** -> § some of the compounds released by lees bind with phenolic compounds in grapes ○ **Bind w/ wood compounds -> reduced astringency and modified wood flavors** § Some compounds from lees also bind with certain extracts from wood - the tannins and wood flavors ○ **Interact w/ existing ACs - create lees aroma/flavors ** complex as compounds released by yeast react with aroma compounds already in the wine § more pronounced in whites = yogurt, dough, biscuit, toasted bread
Maturation
What is impact of length of time on lees?
- Short - balance high acidity - eg Muscadet sur lie
- Medium - add texture/mouthfeel - eg Chard
- Long - add flavors/aromas - eg Champagne
Maturation
What are the chemical/physical impacts of lees (whites)?
What are key considerations?
○ Whites - lees aging helps stabilize against unstable proteins that cause hazing; also protect from O2 allowing slower more controlled exposure during mat and reducing amt of SO2 needed
○ Considerations -
§ If lees too thick - esp for gross lees - can produce volatile, reductive sulfur compounds -> at some levels add positive matchstick/smoke aromas but if not controlled can have too much reduction and add bad aromas of rotten eggs
§ Lees provide nutrients for microbes - can assist growth of lactic acid bacteria for MLC but can also encourage growth of spoilage orgs like Brett
Maturation
What is battonage?
Stirring of wine while in contact with lees
Maturation
What are economic considerations of lees aging?
○ Inc time wine is stored at winery inc final cost
○ Wines on lees - esp gross lees - need more monitoring and may need stirring = labor cost
○ If wines being barrel aged, not likely incremental cost for lees aging tho stirring can add labor cost if there are a large number of barrels
Maturation
What is blending?
When does it happen?
What might it involve?
○ Mixing together of 2 or more batches of wine - vs mixing of 2 diff substances (e.g. adding RCGM to sweeten wine)
○ Can be done during any part of winemaking process-> most often done just before finishing and packaging
○ Blending can be done with wine from different
§ varieties
§ locations - vineyards, regions, countries
§ growers selling grapes must or juice
§ vintages
§ treatments during winemaking - free run vs pressed juice
§ Wines treated exactly same but stored in diff vessels for logistics
Maturation
How does law impact blending?
Examples?
○ Local laws often define what can/can’t be blended, in what proportions
○ EU - PDO designated wine 100% of fruit must come from defined geo area
○ Brunello DOCG - must be 100% sangio vs Chianti Classico DOCG can be blended
Maturation
What are 7 main reasons for blending?
Examples?
○ Balance of wine -> better quality ex - blend batch from warmer site w/ cooler site to balance acidity; blending across var common way to achieve this
§ Ex Bordeaux - Mer provides body and ripe plummy fruit to CS blend which can be too tannic if not fully ripe
○ **Consistency** - within vintage as variation among bottles w/in vintage seen as fault; also across vintages for certain styles § Ex for style reasons - sherry and NV sparkling § Consumer expectations- esp inexp high vol wine ○ **Style** - winemakers often have a "house style" or to make quality levels within their range (mid-priced and prem) § Ex some rose made by blending white and red - allows for precise control over color and flavors ○** Complexity** - can add flavors, aromas and other char ○ **Minimize faults** - blend to correct faults in a batch (sterile filter batch with VA with non-faulty batch to lower concentration/perception of acetic acid) ○ **Volume** - small vineyards likely blend across vineyard sites to inc volume of wine for sale; also in poor vintages may need to blend purchased grapes/must/ wine ○ **Price** - many inexp or mid-priced wines need to be blended to economically achieve specific style/quality level § Ex - blend chard with Trebb or Sem which are cheaper to buy
Maturation
Why do winemakers choose NOT to blend?
○ Single vineyard ->maint char of fruit and terroir; can often be sold for more $
○ Maintain var char - some var would lose distinctive char - SB, Riesling
Maturation
How is blending process usually done?
What is optimal time to do it? Example?
○ Usually starts with blending trials - using measured cylinders and small vol of wine to det prop for blend
○ Req high level of skill/expertise -> esp blending younger wines meant for aging - estimate how blend will develop in future
○ Best done before stabilization to prevent instability from happening due to blend - ex tartrate stability dependent on pH level which can be impacted by blending wines with diff pH levels
