Chapter 18 - Red Winemaking Flashcards
What are the 3 main components winemakers are most focused on extracting in red winemaking?
Tannin
Anthocyanins
Flavors from skins
3 factors that affect extraction:
- Temperature - the higher the temp, the greater the extraction
- Length of time on skins - the longer time the skin is in contact with the juice (and evenly spread out throughout the juice), the greater the extraction
- The medium in which extraction takes place - anthocyanins are more soluble in water solutions, tannins are more soluble in alcoholic solutions
Describe the relationship between anthocyanins, tannins, and oxygen
Anthocyanins provide the color of the wine. However, it is unstable by itself and can easily be lost during lees aging, and by SO2. Tannins can stabilize color by binding to anthocyanins and oxygen aids this process (hence why oxygenation is promoted in red wine fermentation and aging)
What is a con to producing low tannin, fruity reds with macerations using heat? What else can you do with this juice?
If the juice is pressed off the skins before fermentation because a low tannin, fruity style is desired, color instability becomes a common problem because not enough tannins were extracted
Therefore this is only used to make cheap to mid-priced wines meant to be consumed shortly after production
You can also blend this juice into higher quality wine and bring juicy, fruity flavors to the blend
What is the key aim of maceration before fermenation? What are the 2 methods?
Extract color and flavors without extracting tannins
cold soak
Maceration using heat (flash détente and thermovinification)
Describe the process of cold soaking
Crush the berries
Juice and skins are chilled to 4-10C (reduces oxidation, spontaneous ferm, and microbial spoilage)
Lasts 3-7 days
Usually uses punching down and pumpking over to mix up the skins and juice to aid extraction - this also prevents growth of spoilage organisms that need O2 like acetic acid bacteria on the caps
Gentle technique suitable for premium wines
Slow extraction that can be monitored and controlled
Costly - energy required to chill the wine, taking up valuable tank space for a period of time
Whats the main difference between cold soak and maceration with heat?
`maceration using heat extracts high levels of anthocyanins and flavors quick;y
Describe flash détente
Destem the grapes (don’t crush)
Quickly heat to 85-90C for a couple minutes and then rapidly cool under a vacuum
This causes the skins to bust, allowing the rapid color and flavor extraction
Short time prevents ‘cooked’ flavors
Costly bc of vacuum system
Generally only used by high volume wineries
Describe Thermovinification
Crush the berries
Heat the must to 50-60C for a number of minutes to several hours
When would you prefer using maceration using heat?
If the grapes have been affected by botrytis (grey rot) bc the high temp denatures laccase (the enzyme produced by the rot that oxidizes wine components and is relatively unaffected by SO2)
Flash détente can be used to treat smoke taint
Why do some critics not like maceration using heat?
Causes a reduction in more suble varietal characters
Maceration during fermentation techniques:
- Cap Management
- Must Concentration
- Co-fermentation
What is the cap during fermentation?
The grape skins that rise to the top of the liquid and remain there bc of CO2
Why is it important to mix the cap and juice?
- Without mixing, the skins macerate only in teh same small volume of liquid they’re in contact with. This liquid becomes saturated with color, flavor, and tannins and no longer extracts more
- A dry cap allows bacteria to convert alcohol into unwanted acetic acid (O2 exposure)
- Avoids over production of reductive sulfur compounds
- Helps distribute the heat produced during fermentation
What aspects of cap managment impact the style of wine made?
- The cap management technique used
- The frequency of mixing and duration of mixing
- The timing of the mixing influences the compounds extracted
During cap management, how does the timing of the mixing incluence what compounds are extracted?
More mixing at the start of fermentation with less in the end will extract more color and less tannin
Vice versa
Cap Management Techniques:
- Punching Down
- Pumping over
- Rack and return
- Ganimede tanks
- Rotary fermenters
French term for Punching Down
Pigeage
Describe Punching Down
A plunger submerges the cap by hand or mechanized
Doing it by hand is labor intense and taxing and therefore ony suited to low volume, premium wines
Small open top vessels must be used (only way to physically punch down teh cap and ensure adequate mixing)
Gentle process
Used on several grape varieties
Describe Pumping Over
Juice is taken from near the bottom of the vessel and sprayed over the cap
As the juice passes through the cap, it extracts color, flavor, and tannins
Very gentle and generally must be paired with punching down or rack and return for enough extraction
Can be done aerobically and anaerobically
Commonly used on all varietals
For wines of all price points and qualities
Suitable for large vessels
Can be mechanized - can be pre-programmed to occur at a certain time for a certain duration
French term for Pumping Over
Remontage
Describe Rack and Return
Similar to pumping over but the juice is pumped into another tank and then returned
As the juice is pumped back into the tank, it is sprayed over the cap, breaking it up and mixing the juice and skins thoroughly
More extractive than pumping over or punching down - therefore can only be used 1-3 times during fermentation
Used for reds with medium to high levels of falvor, color, and tannin desired (cab, syrah)
Cannot be fully automated
Requires another clean vessel to be available
French term for rack and return
Delestage
Describe Ganimede Tanks
Specialized takms that bubble CO2 up through the must, causing pressure build up under the cap and bursting the cap
Relatively extractive like Rack and return
Used for wines with medium to high tannin, color, flavor extraction (cab, syrah)
Can be fully automated
Tanks are expensive
O2 can be used instead of CO2
Describe Rotary Fermenters
Horizontal, closed, SS tanks where the tank rotates and has internal blades that break up the cap
Horizontal position increases the surface area of skins that touches juice
High level of extraction
Used for med to high level color, flavor, tannin extraction wines (cab, syrah)
Highly mechanized - can be programmed to rotate at certain times for a certain amount of time
Commonly used for high-volume, inexpensive, or mid-priced wines with ok quality
Costly
What are the gentle cap management techniques?
Punch Down
Pumping Over
What are the extractive cap management techniques?
Rack and return
Ganimede tanks
Rotary Fermenters
Describe must concentration
increasing color, flavor, and tannins by drawing off the juice thats lighter in color, flavor, and tannin
This concentrates the remaining must but decreases overal volume (price implications)
Drawn off juice usually used to make rosé (saignée method)
Describe co-fermentation
Fermenting usually a small percentage (up to 5%) of white grapes to take advantage of some of the phenolic ocmpoudns found in white grape varietals that can increase color intensity adn stability through binding with anthocyanins
Popular in Cote Rotie (Syrah and Viognier)
No cost incurred
3 types of whole berry/bunch fermentation
- Carbonic maceraiton
- Semi carbonic maceration
- Whole berries/bunch with crushed fruit
Whats important about the stems in whole bunch fermentation? What varietals do you usually not use it for?
Must be ripe
Contribute spicy, herbal flavors and tannins
Unripe stems give green flavors and bitterness
Varietals naturally high in tannins (ie cab)
What is the objective and what happens during whole berry/bunch fermentation?
Create an oxygen free environment for the uncrushed fruit
Grapes change from aerobic respiration to anaerobic metabolism, casuing some of the sugar to convert to alcohol without yeast (intracellular fermentation)
Malic acid also breaks down to create ethanol (up to 50%) (increases pH)
Glycerol levels rise - adds texture and aromas (kirsch, banana, bubble gum, cinnamon)
Describe Carbonic Maceration process
Placing whole, uncrushed bunches into a vessel filled with CO2
Intracellular fermentation starts and produces ~2% alcohol by volume
Grapes are then crushed normally or the grape skins start to split and juice is released
Normal fermentation commences
Juice is drained and grapes pressed - blended
Fermentation via yeast completes the process
What is the style of wine that results from carbonic maceration?
High color extraction
Low tannin extraction
Distinctive notes from intracellular fermentation & fruity varietal notes
Oak gnerally not used
Describe intracellular fermentation
Alcohol conversion without yeast
Grapes change from aerobic respiration to anaerobic metabolism, causing the sugar in the grapes to convert to alcohol
Describe the Semi-Carbonic Maceration process
Vessel is not filled with CO2
Whole bunches added in
Bottom grapes are crushed by the weight of the grapes and some juice is released
yeast starts to ferment that juice, producing CO2 that fills the vessel and the remaining intact grapes undergo carbonic maceration
When teh intact grapes begin to split and release their juice, the grapes are pressed and the yeast complete the fermentation on or off the skins
Post fermentation maceration and maturation in oak optional to add complexity
This can help better integraiton of aromas from intracellular fermentation with aromas from teh grape variety
Result: wines with more fruitiness and a softer mouthfeel than crushed fruit fermentation
Used to make fruity style wines of all varieties
Describe Whole Berries/bunches with crushed fruit
Mix whoel berries/bunches with crushed fruit in the fermenting vessel at the start of fermentation
Intracelluluar fermentaiton happens bc the whole bunches are submerged in the crushed grape juice
More carbonic characteriestics can be achieved by increaseing hte amount of whole berries/bunches used
Whoel berries progressively crushed as cap is regularly pumched down
Post-fermentation maceration and oak optional
Gives smoother texture and more vibrant and fresh primary aromas than crushed fruit fermentation
Used on a wide variety of grapes
What kind of oak is generally used for red winemkaing and in what orientation?
Generally large vats
Barrels are kept on their sides with one of hte heads removed to form a very small open top fermenter
Why do winemakers ferment in oak?
Gives a rounder mouthfeel and leads to better integration fo oak compounds during maturation
Why do winemakers ferment in cement and SS?
Retain fruit flavors
How long can post-fermentation maceration last?
A few days to a few weeks
Why do post-fermentation maceration?
Further extract tannins and encourage the polymerisation of tannins
This improves tannin structure nad texture and the wine’s aging potential
Why have MLF occur in oak?
Better integration of oak characteristics during maturation
Whats the typical amount of time mid - premium wines mature in barrel?
6months - 2 years
Why mature in barrel?
Soffen tannins
Develop tertiary aromas and flavors for complexity and quality
Pros and cons of aging red wines on lees?
Pro: soften tannins
Con: loses color intensity
*Not typical to leave gross lees or stir the lees in reds
