Wine making 11~15 Flashcards
How reducing alcohol?
- Add water (but dilute aroma and acid)
- Reverse Osmosis (membrance seperation technique, water back)
- Vacuum Distillation(Vacumm-lower boiling point, lost volatile aroma back)
- Spinning Cone(Thermal distillation spreads the wine to a very think film)
Deacidification?
1.Calcium carbonate(chalk)
or
Potassium carbonate
formation n precipitation of tartrates
- Ion exchange
15.1.3 Fining?
1). Unstable proteins(Bentonite)
2). Phenolic (Unstable colour and bitterness)
3). Colour and off-odours (Charcoal)
2). Phenolic (Unstable colour and bitterness)
- A
- Egg white (fresh or powder form)
remove harsh tannin
// clarify wine (gentle) - Gelatine (protein collagen, pork)
removes bitterness n astringency in red
//removes browning in white
–strip flavour
–risk of protein haze forming later
M,W - Casein (milk derived protein)
removes browning from white
clarify wines
M,W
2). Phenolic (Unstable colour and bitterness)
- B
- Isinglass (protein collagen, fish bladders)
clarifies white, give bright appearance
–formation protein haze
–creation of a fish smell - Vegetable protein products (potato, legumes)
- PVPP (insoluble plastic in powder)
removes browning
// removes astringency from oxidised white
(gentler than charcoal, rarely in red but can reduce astringency and brightening colour)
3). Colour and off-odours (Charcoal)
removes brown colour n off-odours
–desirable aromas n flavour
->only one batch of the affected wine and then blend it with the rest to reduce this effect
- Filtration
Physical separation by passing it through filter medium
1) Depth filtration
A. Diatomaceous earth (DE)
B. Sheet filters
2) Surface filtration
A. Membrane filters (sterile filtering)
B. Cross-flow filters
1) Depth filtration
//Traps particles in the depth of the material
// Can cope w/ fluid with many particles (e.g. lees)
// X block easily
– X absolute filter
->too much pressure, filter used too long
->some particles make their way through the filter
A. Diatomaceous earth (DE)
B. Sheet filters
A. Diatomaceous earth (DE)
Pure silica & inert (most common form of depth filtration uses DE)
//DE is wetted and used as a filter medium
//Wine is sucked by vacuum from the outside of rotary drum through DE to inside of drum
//Filter thick n cloudy wine (e.g. lees)
//Oxidative process (drum is exposed)
//Enclosed DE filter (inert gas like nitrogen)
//DE comes in a range of particle size
->remove large or very small (yeast) particles
//Initial investment, per litre cost is small
B. Sheet filters
aka ‘plate n fram’ or ‘pad’ filters
//Pass through a sheet of filtering material
//More sheets = quicker the wine
//Very fine graded sheets can remove yeast
//Initial investment, filter sheets cost is low
//Trained personnel must operate
2) Surface filtration
//Stops particles that bigger than the pore sie of the filter
//Absolute filters
A. Membrane filters (sterile filtering)
B. Cross-flow filters
A. Membrane filters
aka ‘sterile filtering’ or ‘cartridge filters’
//Slower than depth filter <- pores are smaller -> must be pre-filtered(depth filtration) if not blocked
//Usually for final precaution
//Yeast n bacteria removed ->microbiologically stable -> common in bottling n packaging
//Initial is small but cartridge expensive n ongoing cost (differ from depth)
B. Cross-flow filters
aka ‘tangential filters’
//Wine pass through filter, cleaning the surface of the filter
//High load of particles or less very quickly
// x replacement sheets, cartridges or earth but machine is expensive
//Suit for large or well-funded wineries
15.2 Stabilisation
Several winemaking interventions -> avoid undesired effect in the finished wine
//Inc. unwanted hazes, deposit and rapid changes in the wine(browning)
- Protein Stability (Fining with bentonite)
- Tartrate Stability (+fining n filtering = clarification n stabilisation)
- Microbiological Stability
15.2.2 Tartrate Stability
- A
Harmless deposit of crystal
- Cold stabilisation
tartrates are less soluble at cold temp then filtered out
//requires equipment n energy
//colloids must be removed by fining as could prevent crystals forming - Contact process
quicker, continuous , more reliable, cheaper than cold stabilisation
//potassium bitartrate added -> speed up crystallisation process (usually cool around 0)
->after 1~2 hours filtered out - Electrodialysis
uses a charged membrane(막) to remove selected ions
//high initial investment n less energy n Faster (total cost are lower than cold)
15.2.2 Tartrate Stability
- B
- Ion exchange
x remove tartrates but replace potassium n calcium ions w/ hydrogen or sodium ions
-> not drop out of solution - CMC (Carboxymethlcellulose)
cellulose from wood
//prevent tartrate from developing to a visible size
//widely for inexpensive white, x suit for red (react w/ tannins ->cause haze)
//cheaper than chilling -> keep wine stable for a few years - Metatartaric acid
prevent growth of (potassium, calcium) tartrate crystal -> x need cold stabilisation
//but compound is unstable, effect lost over time (esp. stored at high temp) -> good for early consumption
//quick and easy process
//for red (CMC is effective and last long for white)
15.2.3 Microbiological stability
residual sugar -> liable to re-ferment in bottle -> removing yeast through sterile filtration OR add sorbic acid n SO2 (inhibit yeast growing) (some people smell sorbic at low level)
few microbes can live in low pH, high alc level (except
1. lactic acid bacteria -> malo -> cloudiness
//malo completed or filter
2. acetic acid bacteria
3. Brettanomyces (a spoilage yeast)
//filtering or DMDC before bottling (inactivate Brett)
