Flashcards in Wine making options for Red/White/Sweet Wine Deck (49)
What is the main purpose of Leaving crushed white grapes on the skins?
To enhance the extraction of aroma and flavor compounds
What are some of the reasons why winemakers may choose not to have skin contact on white wines?
- Any tannins extracted would have little to no time to soften
- Not suitable for wines meant to be drunk early
- If the fruit is under-ripe, skin contact could cause the extraction of bitter flavor and astringent tannins
- Slows Processing
- Another procedure that requires time and labor
Name some of the benefits of
pressing white grapes whole clusters?
- Lowers the chance of oxidation, especially if inert gases/dry ice is used in the press
- One of the gentlest forms of pressing
-Provides juice that is low in solids, tannins, and color
- Stems help break up the grape skins and provide channels for the juice to drain
Is whole cluster pressing an option for machine-harvested grapes?
No, machine harvested fruit is already de-stemmed
What is the free run juice? How does it differ from the press juice?
- It is the juice that escapes from the grape as soon as it is crushed
- It is typically the juice that is lowest in solids, tannin, and color.
- Press juices contain more solids, and contains lower acidity and less sugar
Describe what press fractions are and how they may be used in the final wine (can apply to both red and whites)
- Press fractions are juice pressed at different levels
- The press fractions and generally higher in phenolics and color pigments
How can different levels of solids in the must during fermentation affect the final wine?
- Higher portions of solids can add texture (skins and stems will add tannins)
- High levels of solids can also give a greater range of flavors
- Lower level of solids are better for retaining fruity aromas
- High solid fermentations can also lead to reductive flavors (could be a positive or negative)
- Low levels of solids could lead to a stuck fermentation due to lack of nutrients for the yeast
What is DAP?
Diammonium Phosphate, an additive used to feed yeast nitrogen to avoid a stuck fermentation
Does clarification happen before or after alcoholic fermentation in white wines?
It generally happens before alcoholic fermentation
What steps are involved with clarification?
- The suspended solids fall to the bottom of the container over time (generally between 12-24 hours)
- During that time the must is chilled to 4°C/39°F to avoid any kind of spoilage and spontaneous fermentation
What is it called when the winemakers separate the solids and clear juice/wine
Does Sedimentation take longer in tall vessels or short vessels?
Sedimentation may be the cheapest way to clarify wine/must, but what is the trade off?
- It is much more time consuming
- It is a batch process
- The cost of keeping the wine chilled must also be factored into the final price
What are two other ways to clarify the must aside from sedimentation in white wines?
Flotation and Centrifugation
Flotation is where different gases are used to create bubbles. As the bubbles rise up, they bring some of the solids in the must up with them.
What else must be added to the must for flotation to be effective?
Some kind of fining agent must be added so that particles can bind together
Flotation can be used on must and wine, right?
No, it is used to help clarify the must of white wines
What is a centrifuge?
A machine that has a rapidly spinning container with uses centrifugal force to separate the solids and liquids
What are the key ways of producing wines with some residual sugar?
- Concentrating sugar in the grape must
- Stopping the fermentation before dryness
- Blending in a sweetening component to the wine
What is the German term for unfermented grape juice?
Describe what RCGM is
RCGM is just the sugar from the grape, therefore it is more neutral. Smaller amounts are need to sweeten a wine this way
True or False,
Anthocyanins are stable as single molecules?
False, they are not stable and the color they provide can be lost.
Anthocyanins become stable when they bind with tannins which happens when the anthocyanins are exposed to oxygen.
Most of the red wines produced are crushed and de-stemmed before fermentation. What are the different maceration options for winemakers?
- Cold Soaking
- Flash Detente
What is cold soaking?
A cold maceration where the juice and skins are chilled down between 39-50°F to reduce instances of oxidation, microbial spoilage and spontaneous fermentation.
It generally last 3-7 days with the juice being punched down or pumped over.
How is thermovinification carried out?
The must is heated up to 122-140°F and left there for either a number of minutes up to several hours.
What is Flash Detente?
De-stemmed grapes are rapidly heated up to 185-194°F and then cooled under a vacuum. The whole process takes as little as 2 minutes to avoid cooked flavors.
This process also burst the grape skin cells open, allowing a rapid extraction of tannin and color.
What are the main issue with wines made via Flash Detente and Thermovinification?
They tend to have issues with color stability.
Flash Detente and Thermovinification can help manage grapes afflicted with what fungal disease and vineyard hazard?
Flash detente can help with grapes afflicted with smoke taint and grey rot.
Thermovinification can only help with grey rot.
What are the different cap management techniques winemakers can use during fermentation?
- Punch downs
- Pump overs
- Rack and return
- Ganimede Tanks
- Rotary Fermenters