Tartrate Stability Flashcards
KHT
Potassium Hydrogen Tartrate
Crystallization Phenomena in wine
Because supersaturation is a metastable condition, the system needs energy to pass to a more stable configuration. Wine needs energy to crystallize KHT
What are the two variables for measuring the supersaturation domain
- Conductivity
- temperature
What affect does temperature have on crystallization
The soluability of a liquid is lowered with the temperature so there is more precipitation at lower temperatures.
What role does wine aging play on crystallization
Wine aging can modify the stability resulting in potential precipitation
Role of proteins with tartrate holding capacity in wine
We have a larger supersaturation domain
Role of Protein and tannin with tartrate holding capacity
We have a more narrow supersaturation domain
Role of protein and more tannin with tartrate holding capacity
We have the narrowest supersaturation domain
Nucleation
essentially crystallization, when we have clusters that combine into a nucleus.
True or Flase: In every wine there is exceeding KHT
True
How to predict KHT instability (3)
Chemical method
Physical method
Freeze Test
How to check stability (2) and 3 benefits
- Minicontact test
- Saturation temperature test
- no operator error
- computer data managment
- Graphed results
How to check stability (2) and 3 benefits
- Minicontact test
- Saturation temperature test
- no operator error
- computer data management
- Graphed results
Minicontact test
Assessment of KHT stability at 0 degrees C in the conditions of the wine in that precise moment. If the wine is within 5% of a drop in conductivity, its stable, any more and it is considered unstable. Lesser degrees indicate the wine as being more stable
Role of Crystallization and saturation temperature
The farther apart they are the more difficult to stabilize
Crystallization Temperature
Crystallization is closer to stability with higher temps and wines that have saturation at high temps
Saturation Temperature
White and Rosés are stable until 12 while reds are stable until 15. Reds have more natural stability
two other devices to check stability
- Stabilab
- Mextar
Process by which to stabilize
Rapid Cold Stabilization
Different approach to the problem: non subtractive methods
Colloids as Adjuvants
4 Colloidal Adjuvants
- Metatartaric Acids
- Arabic Gum
- Manoproteins
- carboxymethylcellulose
