18. Specific options for red winemaking Flashcards
What 3 factors affect extraction in red wine?
- Temperature
- Time on skins
- The medium in which it takes place
How does temperature affect extraction?
higher temps result in greater extraction
How does times on skins affect extraction?
generally, the longer the juice/wine remains in contact with the skins the great the extraction. The more the skins are mixed through the juice, the greater the extraction
How does the medium that extraction takes place affect it?
Tannins are most soluble in alcoholic solutions
Anthocyanins are most soluble in aqueous solutions (grape must)
What are anthocyanins?
The source of color in young red wines.
How can the color that anthocyanins provide be altered?
- altered or lost in the process of different winemaking procedures, such as lees aging or additions of So2
- become paler over time
Anthocyanins alone are unstable. How do they become more stable?
Combining with tannins. Oxygen facilitates this reaction, therefore winemaking processes that encourage gentle oxygenation of the wine can help promote color stability.
What are the two options for maceration before crushed fruit fermentation?
- Cold soaking
- macerations using heat
Describe cold soaking AKA pre-fermentation maceration
- Juice and skins chilled to 39-50F to reduce spoilage, oxidation, risk of spontaneous fermentation.
- 3-7 days, usually with punching down/pump over to mix skins and juice to aid extraction and to avoid acetic acid bacteria build up.
- cold temps = slow extraction
- Common on pinot noir to promote color intensity. PN has low levels of anthocyanins
- Takes time, uses tank space so suited for low-volume wine.
What are the two methods of macerations using heat
- Flash Detente
- thermovinification
Macerations at higher temps give what?
greater extraction
Describe Flash Detente
- Destemmed grapes heated to around 185-194F then rapidly cooled under a vacuum. Takes about 2 mins.
- Very rapid extraction
- Risk of cooked flavors
- Usually only used in high volume winery
- Used as a treatment for smoke taint
Describe thermovinification
- Heating must to around 122-140F for minutes to hours
- Higher the temperature, the shorter the maceration time
Besides heat, what do Flash Detente and Thermovinification have in common?
- Juice may be pressed off skins before fermentation if a low tannin, fruity style is desired. However, this leads to color instability bc not enough tannin to bind with anthocyanin
- Can be beneficial if grapes are affected by grey rot.
Name the 5 cap management techniques
- Punch down
- Pump over
- rack and return
- Ganimede tanks
- Rotary fermenters
Why is cap management important?
- It is important to mix the skins with the juice or wine during fermentation. Otherwise the skins would only macerate in the small volume of liquid surrounding them.
- Dry caps allows bacteria to convert alcohol into acetic acid
- helps aerate the must
- helps distribute heat
- influences wine style with tannin extraction, color extraction, avoids reductive sulfur compounds.
How does the timing of mixing within fermentation influence what compounds are extracted?
more mixing at the start of fermentation with less mixing at the end will extract more color and less tannin, whereas mixing more at the end of fermentation will extract a greater amount of tannin.
Describe the process of punching down
a plunger is used to submerge the cap of skins in the liquid
- either mechanized or by hand
- labor intensive by hand, so best suited to low-volume premium wines.
- carried out in small, open-top vessels
- gentle process
Describe the process of pumping over
- juice/wine is taken from near the bottom of the vessel and sprayed over the cap of skins.
- usually around 1/3 to 1/2 of the liquid is sprayed
- extraction is gentle and usually punching down or rack and return is required to extract enough color, flavor ad tannin
- Can be programmed
How can pumping over becomes an aerobic process?
-Splashing the juice/wine against the inside wall of the open vat which exposes the must to oxygen. This is beneficial for yeast health and avoiding off-flavors
How can pumping over become an anaerobic process?
inside closed vessels with a hose attached to a tap at the top of the vessel or by keeping the hose close to the cap in an open vessel.
Describe rack and return
- similar to pumping over
- juice pumped from one vessel into another and back into original
- more extractive than pumping over, use maybe 1-3 times
- often used along side pumping over
- most commonly used for extracting high levels of flavor, color, tannin (cab, syrah)
- cannot fully automate.
What is a Ganimede tank and how is it used?
- Specialized tanks that bubble CO2 up through must/wine
- Pressure builds, cap bursts, quickly breaks apart the cap
- very extractive
- oxygen can be used instead of CO2 if desired.
Describe rotary fermenters
- cap is mixed in a rotating tank
- very effective, highly programmable
- usually for high-volume
- expensive
- not as precise
In addition to cap management, what other two techniques can be used?
- must concentration (via Sagniee)
- Co-fermentation
What are the 3 types of whole berry/bunch fermentations?
- Carbonic maceration
- Semi-carbonic maceration
- Whole berry/bunches with crushed fruit
What are important considerations if a winemaker intends to use whole bunches?
- -grapes must be hand harvested.
- stems must be fully ripe otherwise they can add unpleasant green flavors and bitter tannin
- ripe stems can add spicy and/or herbal aromas and tannin
- Stems can also be added to crushed fruit fermentations to provide some tannins and spice
What is the objective of whole berry/bunch fermentations?
-To create an oxygen-free environment for the uncrushed fruit
What are the outcomes of the lack of oxygen with whole berry/bunch fermentation?
- Grapes change from aerobic respiration to anaerobic metabolism. In the anaerobic process, some sugar in the grape is converted to alcohol - this occurs without involvement of yeast and is called “intracellular fermentation.”
- Malic acid is broken down to create ethanol which reduced magic acid levels by up to 50%
- Glycerol levels increase which add texture and a range of distinctive aromas - kirsch, bubblegum, etc
Describe the process of carbonic maceration
- Uncrushed berries are placed into vats which are filled with CO2 to remove oxygen.
- Grapes are either crushed by their own weight or manually. Fermentation begins.
- Grapes are pressed
- Press juice and free run are usually blended
- Yeast completes fermentation off the skins
- Extract color, but very little tannin
- Resulting wines are fruity, low tannin, distinct but not necessarily complex
Describe Semi-Carbonic maceration
- Similar to carbonic maceration, but here, the CO2 produced by fermentation fills the tank.
- Ambient yeast starts fermentation, cultured yeast may be added
- Grapes pressed, yeast completes fermentation off the skins
- Produces a wine with slightly more concentration, body, tannin, and longer aging potential
- Alcoholic fermentation continues and may involve punching down/pump over
- Alc fermentation may be followed up by post-fermentation maceration or maturation in oak for complexity
- This approach can lead to better integration of aromas from intracellular fermentation, more fruitiness, softer mouthfeel than crushed fruit fermentations
- EX: Pinot noir, gamay, tempranillo
Describe mixing whole berries/bunches with crushed fruit
- A further variation is to mix whole berries/bunches at the start of fermentation
- stems must be ripe if using whole bunches
- More “carbonic” characteristics can be achieved by increasing proportion of whole berries/bunches
- cap is regularly punched down
- similar to semi-carbonic, a period of post fermentation maceration and/or oak maturation may follow
Describe the effects of fermentation temps and vessels for red wines
- high temps = high extraction, but high temps can evaporate volatile fruity aromas
- Fruity, low-tannin wines = cool temps
- higher concentration = warm temps
- temp can be monitored throughout fermentation to control extraction and promote health fermentation to dryness
- stainless steel, concrete, large wooden vessels can be used.
- Vessels can be open or closed
- Oak is thought to give a rounder mouthfeel and better integration of oak compounds during maturation
- Stainless and concrete help retain fruit flavors
Describe post-fermentation maceration
- Thought to further extract tannins and encourage polymerization of tannins with the aim of improving tannin structure, texture, wine’s aging potential
- Generally for premium and super-premium wines intended for aging
When does pressing take place?
-when no more extraction is desired.
What happens during pressing?
- press wine may be blended with free run as a blending component to add color, flavor, tannin
- the quality of the fruit management and of the press are important considerations with high quality grapes and the gentle first pressings’ ability to enhance tannin structure of a wine
How does the wine style determine the timing of pressing?
- carbonic maceration styles, pressingly occur when the fermenting must reaches 2% abv to produce a wine with medium levels of color but low levels of tannin
- After post-fermentation maceration to maximize tannin structure
- straight after alcoholic fermentation or just before the end. Thought to lead to a better integration of oak flavors and rounder mouthfeel
Describe MLC for red wines
- routine for red wines
- vessel in which is happens may vary
- conversion in oak may lead to better integration of oak characteristics during maturation
- winemaker can decide if it takes place during or after fermentation
- Winemaker may adjust acidity at this stage
Inexpensive red wines usually get what as oak treatment?
staves or chips
Oak maturation in red wines is a gentle form of what?
oxidation
What does gentle oxidation of red wines during maturation lead to?
development of tertiary aromas and flavors, softening of tannins
Why might new oak be used for red wine maturation?
if the winemaker feels the flavor of oak (vanilla, clove, etc) would enhance the complexity
Why might a winemaker choose not to mature in oak o use a minimal amount of aging in old oak?
winemaker wants focus to be on primary aromas and flavors
What can lees aging do for red wines?
- can help soften tannins
- can possibly reduce color intensity
- not typical to stir lees when making red wines
What processes are usually combined with pumping over?
- Rack and return
- punching down
What processes are usually combined with cold soaking? Why?
Punching down and pumping over
To mix skins with juice and to aid extraction and avoid acetic acid bacteria from building up
What two fermentation choices does a winemaker have after grape reception?
Crushed fruit fermentation
Whole bunch/berry fermentation
How are the vast majority of red wines made?
By destemming and crushing the fruit before fermentation.
In crushed fruit fermentations, when may pre-fermentation must adjustments be made?
adjustments can be made to the acidity, sugar, and tannin levels as needed.
