D17: Wines with Residual Sugar Flashcards
What two styles do wines with residual sugar usually come in?
- Inexpensive wines: low to mod residual sugar makes them more appealing to larger consumer audience
- sweet wines: higher residual sugar level and are syrupy in texture
What two ways can you prematurely stop the fermentation?
- chilling must
- adding SO2
- then filtering to remove yeast
- gives winemaker control over balance of alcohol and sweetness
How can you concentrate the must?
- reducing water content in grape
- this process also concentrates acidity and flavour
- helps keep wine in balance so that sweetness doesn’t become too dominant
- can add own flavours through process of concentrating sugars and gives more complexity (dried fruit characters)
What are the challenges for producing a sweet wine?
- very low volume of juice obtained and sugary pulp is hard to extract during pressing
- adds to cost of production for wine so often only prem and super-prem
What is the process of drying grapes ON the vine?
- if left on vine, grape starts to shrivel
- water is lost by GRAPE TRANSPIRATION and therefore causes sugars to concentrate
- flavours in grape continue to develop and become very ripe
- EXAMPLE: - Pinot Gris:
- ripe tropical fruits
- dried stone fruits
- need long, dry autumns so don’t develop grey rot
Grapes dried on the vine can be called:
Late Harvest (or other local name)
Vendanges Tardives (Alsace)
Spatlese (Germany/Austria)
What additional method is there for drying grapes ON the vine?
- cane of the vine is cut or broken off fro the vine before the harvest
- grapes shrivel more quickly than if they were still attached to rest of vine
- concentrates sugars, acids and flavours within grapes
- reduced hang time lowers risk of grey rot
- possible to get grapes with very high levels of sugar without extra-ripe flavours
Used in:
- Jurancon
- Australia
What is the process for drying grapes off the vine?
- grapes are picked and then dried
- can last from days to months depending on drying required and speed of drying process
- bunches of grapes laid out in sun
- need warm climate
- southern Italy
- Spain
OR
- dried in temperature- and humidity-controlled room in cooler climates (as used in production of Valpolicella)
- drying process causes water to evaporate which concentrates sugars, acids and flavours)
- can speed up drying and avoid development of grey rot
- very expensive as need to build specific room
- can be known as PASSITO in Italy (Recioto di Valpolicella and Vin Santo)
Noble Rot
- need BOTRYTIS CINEREA
- also causes grey rot
- here used for sweet wine production
- grapes MUST be fully ripe before development of rot
- grapes must be grown in region which has humid, misty mornings followed by sunny, dry afternoons
* Damp conditions = allow rot to develop on grapes. Fungus punctures skin with MICROSCOPIC FILAMENTS which leave tiny holes* Warm afternoons = slow development of rot and cause water to evaporate from grape which concentrate sugars, acids and flavours
What are the flavours produced by Noble Rot?
- honey
- apricot
- citrus zest
- ginger
- dried fruit
Name the four premium and super premium wines produced from Noble Rot?
- Sauternes
- Beernauslese
- Trockenbeernauslese
- Tokaji
*only use white grapes
What are the pitfalls/risks of Noble Rot
- never uniform spread of rot (- need selective harvesting and skilled workforce )
- very low volume of juice obtained
- doesn’t occur every year so makes wine scarce and expensive
- if conditions are too damp then fungus will develop too rapidly and cause grey rot
What is the processing process for wines make from Noble Rot?
- not easy to process in winery
- fungus contributes an enzyme (LACCASE) which is capable of oxidising a number of components in grape must and wine
- relatively resistant to SO2
- chilling, high doses of SO2 and use of inert gases all options to minimise oxidation of must
- thick, high sugar content must also difficult to press, clarify and ferment
What is the maturation process for wines made from Noble Rot?
- matured in either old or new oak if using neutral grape variety (e.g. semillon)
- gives broader texture to wine
- adds in some flavour (e.g. vanilla)
- use stainless steel or concrete for aromatic varieties
What is the process for freezing grapes on the vine?
- grapes left to hang on vine into late autumn and winter months
- when freezing temps arrive, water in grape pulp turns to ice
- when picked and pressed, the ice remains in the press and sugar content of juice is concentrated
- fermented and stored in stainless steel to retain aromas and flavours of grape varieties
- can use some oak to add extra flavours (vanilla, clove)
- highest quality/low yield: picked late in winter season
- juice yield very low so command prem or super-prem prices
- only in a few regions where weather conditions allow (ones with good freeze/thaw cycles)
- vines needs to be winter hardy and produce grapes with resilient skins that offer protection from disease and can withstand strain of freeze-thaw cycles
- Riesling
- Vidal
- Cab Franc
What is Cryoextraction?
- grapes picked in Autumn and then frozen in the winery
- used by winemakers where don’t have conditions for Eiswein or Icewine
- no risk of leaving grapes for long time on vine which could be lost due to disease or pests
- can’t use Eiswein or Icewine on label
- cheaper than typical eiswein production
Freezing grapes on the vines produces two types of wine:
Eiswein (Germany/Austria)
Icewine (Canada )
- protected terms
- need to follow various regulations in order to use these terms
- e.g. Icewine must be harvested at -8 degrees
What are the advantages and disadvantages of stopping the fermentation so wine is left with residual sugar?
Advantage:
- winemaker has control over level of sugar in final wine
- earlier the ferm is halted, higher the level of residual sugar will remain (but lower level of alc)
- quick, simple, low risk
- good for wines that are inexpensive or mid-priced
Disadvantage:
- don’t get same level of intensity and/or complexity of wines produced
- not really that good quality
What are the two method options for stopping the fermentation?
Chilling:
- chilling must below 10 degrees
and/or
adding high dose of SO2 to inhibit the yeast
- wine then racked off sediment and sterile filtered to ensure fermentation doesn’t start again later
Fortification:
- addition of alcohol to kill the yeast
- radically changes style of wine
What are the benefits of producing a sweet wine by blending in a sweet component?
- easiest way of producing wine with residual sugar
- dry wine is stored until ready to be bottled and then sweetening component blended in
- dry wine less susceptible to microbial spoilage than wines with residual sugar
- winemaker can trial, measure and add amount of sweetener needed to produce style of wine desired
- allows high level of control so can make high volumes of consistent product
- possible to maintain or increase volume of wine that can be produced
- good for high vol inexpensive wines
What are the two sweetening components that can be used to blend into a wine to make it sweet?
- Rectified Concentrated Grape Must (RCGM)
- Unfermented Grape Juice (Sussreserve)
- both are inexpensive
- substance which can be used is often determined by local regulations or PDO laws
- e.g. EU: PDO wines, unfermented grape juice must come from same wine region as wine being made
What is RCGM?
Rectified Concentrated Grape Must
- processed so that just contains sugar from the grape
- neutral
- just need small amounts
- inexpensive
