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