15. Finishing and Packaging Flashcards
1
Q
What is used for protein stabilization?
A
Fining with bentonite
2
Q
How does CHARCOAL work as fining agent?
What type of wine is it commonly used for and why must care be taken?
A
- removes brown colors + some off-odors
- used to create Pale Cream Sherry
- eaily removes desirable aromas + flavors if over-used.
3
Q
Why is oxygen management one of the most important considerations when bottling?
What happens if there is too much / too little?
A
- amount of oxygen in final container determines shelf-life+expected development of wine.
- too much oxygen = premature browning + oxidized characters (loss of fruit, bruised fruit notes)
- too little oxygen = reductive characters e.g. onion, rotten egg aromas.
4
Q
What are the 4 ways to clarify post-fermentation?
A
1) sedimentation
2) centrifugation
3) fining
4) filtering
5
Q
In the context of HACCP, what is an example of a specific hazard and a preventive action plan to handle it?
A
e.g. In a bottling line there is a hazard of glass breaking + ending up in a bottle of wine = hazardous to customer.
Preventive Action Plan = have a detection system to identify the broken bottle and push out the next 3 neighboring bottles automatically.
6
Q
What are the 2 main exceptions to the overwhelmingly preferred option of glass bottles for packaging wine?
A
1) producer markets (e.g. France) where consumers collect wine directly from a local winery in plastic containers for early drinking.
2) bag-in-box markets (e.g. Sweden) where this packaging makes up 50%+ of consumption.
7
Q
Explain how the CONTACT PROCESS works (2):
Pros (4)?
A
- addition of potassium bitartrate to wine speeds up crystallizing process.
- crystals are filtered out before bottling.
- quicker, continuous, cheaper, more reliable.
8
Q
Explain how ELECTRODIALYSIS works:
Costs / Pros (3)?
A
- charged membrane is used to remove selected ions.
High initial investment, but cheaper in the long run.
Uses less energy + faster.
Removes both potassium + calcium ions
9
Q
What is HACCP (3)?
A
- Hazard Analysis of Critical Control Points
- a process in which the company identifies all the possible hazards that could affect final wine quality
- for each hazard, an HACCP document will state how serious it is and how it can be prevented and corrected
10
Q
What are advantages of bag-in-box packaging (5)?
A
- flexible pour size (1 or more glasses)
- protection from oxygen once opened (bag collapses around remaining wine)
- range of sizes,
- easy to store
- low environmental impact (light to transport + recyclable)
11
Q
How does ISINGLASS work as fining agent (2)?
Why must care be taken when using it (2)?
A
- removes phenolics that contribute undesirable colors + bitterness
- protein collagen derived from fish bladders that clarifies white wine = bright appearance.
- over-use = risk of protein haze + fishy smell.
- not suitable for vegetarians.
12
Q
What is bentonite?
How does it affect wine (3)?
A
Form of clay used as a fining agent to absorb unstable proteins/unstable colloidal colouring matter.
- minimal effect on flavor/texture of wine
- leads to some color loss in reds
- produces large amounts of sediment, so some wine is lost during racking.
13
Q
What causes VA to the point that it’s a fault? (3)
How does it affect the wine?
A
1) activity of acetic acid bacteria
2) inadequate levels of SO2
3) excess exposure to oxygen
Results in pungent smells of nail varnish/vinegar.
14
Q
What is pictured below?
What is its purpose?
A
- Membrane filters used for sterile filtration.
- used to remove yeasts and bacteria in order to render the wine microbiologically stable.
15
Q
What can reduce the threat of VA? (5)
A
1) sorting fruit to exclude damaged grapes
2) improving hygiene in winery
3) keeping vessels topped up
4) careful racking (avoiding too much O2 exposure)
5) maintaining adequate SO2 levels
16
Q
Why is a small amount of CO2 in finished (still) wine sometimes desired?
How can this be achieved (2)?
A
- some winemakers prefer a tiny spritz to add freshness, esp. for inexpensive, fresh white and rosé wines.
- either manually add CO2 or bottle wine while small amounts of CO2 remain dissolved from fermentation.
17
Q
What are membrane filters?
What are PROS (2) and CONS (3)?
A
- filters that catch particles (e.g. yeasts/bacteria) that will not go through pore size of filter
PROS: - ensures that wine is completely clear and microbiologically stable.
- initial invenstment of machinery is low
CONS: - slower than depth (pores are smaller)
- wine must be pre-filtered to not clog
- cartridges are expensive to replace.
18
Q
Why can a (still) wine have visible bubbles or spritz in the bottle (3)?
A
- re-fermentation caused by unfiltered yeasts + RS in bottle.
- conscious stylistic choice e.g. Muscadet sur lie or Vinho Verde.
- conscious producer decision to preserve/enhance freshness.
19
Q
Describe briefly the Chain of Certification from ISO to Consumer (5):
A
1) ISO sets the internationally recognized standards.
2) Certification body conducts the audit.
3) Wine company conducts its own audit to ensure conformity.
4) Retailer buys wine with assurance from external audit.
5) Customer buys wine with assurance.
20
Q
What is the total package oxygen of a wine a combination of? (4)
A
1) amount of dissolved oxygen in wine
2) oxygen in head space
3) amount of oxygen in cork/other closure
4) oxygen transmission rate (OTR) of cork/closure
21
Q
What is diatomaceous earth (2)?
2 AKAs?
How does it add cost to a wine?
A
- most common form of depth filtration
- soft sedimentary rock that is processed into pure silica, and therefore inert.
AKA “DE” / “Kieselguhr”
DE must be disposed of responsibly = additional cost.
22
Q
What is the difference between DEPTH FILTRATION and SURFACE FILTRATION?
A
DEPTH: method of filtration that traps particles in the depth of its material that forms the filter, e.g. Diatomaceous earth, Sheet filters.
SURFACE: method of filtration that stops particles that are bigger than the pore size of the filter from going through, e.g. Membrane filters and Cross-flow filters.
23
Q
How does EGG WHITE work as fining agent (3)?
What type of wine is it commonly used for and why?
What consideration must be taken when using it?
A
- Removes phenolics that contribute undesirable color + bitterness.
- used in fresh/powdered form
- high protein content removes harsh tannins + clarifies wine.
- used for high-quality reds because of its gentleness.
- must be noted on the label if sold in the EU due to allergen reasons.
24
Q
Explain the mechanics of Bag-In-Box packaging:
What considerations must be considered by the manufacturer (3)?
What is the shelf life of a wine packaged this way?
Where are wines packaged this way most successful?
A
- Flexible, very thin aluminum foil bag (lined w/plastic) housed within a cardboard box.
- needs slightly higher SO2 level to counter oxidation.
- v. low CO2 to avoid bag bulging/bursting.
- high-quality tap is needed to reduce oxygen ingress.
Shelf Life = 6-9 months.
most popular in Australia (where it was pioneered) + Sweden
25
What influences the number of rackings carried out for a wine (2)?
How does this affect the price of the wine?
What styles of wine are suitable for multiple rackings?
- Depends on size of containers + availability of labor.
- Larger the vessel = more rackings needed
- This adds cost to the wine (sedimentation takes time = wine can't be sold for a while / labor$$$)
- Therefore, sedimentation/racking is usually only suitable for premium/super-premium wines.
26
What are advantages of using a natural cork (4)?
What about its image?
- light, flexible, inert, comes from natural/renewable source
- mainly has a positive image in eyes of consumer; opening a bottle w/a corkscrew is seen as part of the enjoyment.
27
Where and when did bottling wine at the winery become an important means of quality control?
Why did this change happen?
How was wine trasported before this?
Began in Bordeaux in the 1920s as a means of quality control.
This way, the producer could guarantee that the final wine was as intended, not at the mercy of possible blending/alteration.
Before this, wine had been transported in animal skins, terracotta pots and wooden barrels.
28
What is a drawback of using sorbic acid for microbiological stabalization in wines?
- Some people can smell the effects of sorbic acid at very low levels.
29
What is surface filtration?
What are they often referred to as?
What are the two types?
- Method of filtration wherein a wine passes through a "surface" w/ a porous membrane to stop particles that are bigger than the pore size from going through.
- referred to as "absolute filters"
- membrane filters and cross flow filters
30
How does the proportion of wine shipped in bulk compare to that shipped in bottle, both in terms of volume and value?
Marjority of exported wine, both by volume and value, is transported in bottle (60-70% of volume.)
31
What are the 3 categories of common fining agents?
Give a specific example of each:
1) those that remove unstable proteins (ex. Bentonite)
2) those that remove phenolics that contribute undesirable colour/bitterness (e.g. egg white)
3) those that remove colour and off odour (ex. charcoal)
32
What are advantages of using a can (5)?
Why does the inside of the can have to be lined w/plastic?
- lightweight,
- robust,
- easy to open,
- impermeable to oxygen,
- recyclable
Plastic is needed to prevent the wine's acidity from attacking the aluminum.
33
What are some PROS (2) and CONS (2) of using screwcap closures?
PROS: - Ease of opening, no special tools required.
- No chance of cork taint.
CONS: - Different markets view w/different levels of acceptance (e.g. Australia/NZ/UK are more on board)
- Still seen as synonomous w/cheap wines by some (e.g. USA/China)
34
Explain the 2 pictures below:
1) Sacks of diatomaceous earth that can be wetted and used as a filter medium.
2) A rotary vacuum filter; wine is sucked by a vacuum from outside the drum =\> passes through DE to the inside of the drum
35
What are 3 different circumstances in which wines should/shouldn't receive post-bottling maturation?
What are the costs involved with post-bottling maturation at the winery?
- Many wines, e.g. Veneto PG based on fresh, fruity flavors, are best consumed within a year of bottling. This is because maturing them results in a los of primary fruit flavors.
- Others (e.g. German Riesling, Vintage Port, First Growth Bordeaux) develop positively for many years and are at their best after a number of years following bottling.
- Some PDOs have bottle-maturation requirements before sale is allowed e.g. Chianti Classico Riserva DOCG.
Post-bottling maturation at the winery increases insurance and storage costs (having/building suitable facilities).
36
Explain how COLD STABALIZATION works (2):
Costs / Considerations (3)?
- wine is held at cold temps (-4 C / 25 F) so that tartrate crystals form.
- crystals are filtered out before bottling.
Requires equipment and energy$$$ for refrigeration.
Only removes potassium bitartrate, not calcium tartrate.
Fining must occur because colloids can prevent from crystals from forming.
37
What is the advantage of shipping wine in bottle?
The entire product (wine/bottling/labelling/external packaging) is controlled by the producer.
38
The ideal closure for a wine bottle has these properties (4):
5 e.g.s of wine bottle closures:
- protects from rapid oxidation
- is inert (doesn't affect quality of wine adversely)
- easy to remove + re-insert
- cheap, recyclable, free of faults
Natural Cork / Synthetic Cork / Technical Cork / Screwcap / Glass Stopper
39
Explain how CARBOXYMETHYLCELLULOSE (CMC) works:
Costs / Considerations (3)?
- cellulose prevents tartrates from developing to a visible size.
- widely used on inexpensive whites + rosés
- not suitable for reds due to reaction w/tannins + causes haziness.
- much cheaper.
40
What is pictured below?
How does it work (2)?
Wine passing through a Sheet Filter.
- wine passes through a sheet of filtering material.
- the more sheets in the filter, the quicker the total amount of wine can pass through because any portion of wine only passes through 1 sheet.
41
What can reduce the threat of Brett (3)?
1) excellent hygiene in the winery and cleaning of barrels.
2) maintaining effective SO2 levels
3) keeping pH levels low and adding SO2 as soon as possible after malo
42
What are ideal circumstances for post-bottling maturation (4)?
- cool, dark place
- constant temperature between 10-15 C / 50-59 F
- constant humidity
- lying on their sides so corks remain moist
43
What is the difference between quality control and quality assurance?
- quality control: a set of practices by which the company ensures a consistently good quality product
- quality assurance: broader concept that includes quality control -- complete way a business organizes itself to deliver good product consistently and protect itself from legal challenge
44
How does CASEIN work as fining agent (2)?
What is a consideration that must be taken when using casein?
- removes phenolics that contribute undesirable color + bitterness.
- milk-derived protein that removes browning from white wines.
Casein must be declared as an allergen in certain territories.
45
What is depth filtration (2)?
What is the most common form?
- method that traps particles in the depth of the material that forms the filter
- small particles become trapped w/in irregular channels of the filter.
- most common is diatomaceous earth (DE)
46
What is filtration (3)?
What are the 2 main types?
A physical separation technique used to remove solids from a suspension
=\> by passing it through a filter medium consisting of porous layers that trap solid particles,
=\> thus making liquid clear (most common way for clarifying)
Depth filtration / Surface filtration
47
Who carries out and inspects a company's HACCP plan (2)?
How does this effect the winery financially?
- HACCP is carried out by the company w/no checking/auditing by a third party.
- However, the plan itself and actions to implement it are available for inspection.
- This adds considerable time investment, and therefore $$$.
48
What are the two types of container for bulk shipping?
How do they compare to each other?
1) flexitank (more common): single-use, polyethylene bag that fits into standard container, cheaper.
- bag is coated w/barrier to prevent taint and oxygen ingress.
2) ISO tank: stainless steel vessel built to ISO standard that can be used many times and have additional insulation (incurs additional cost, aka 'reefers').
49
What are the 2 main issues with using natural corks?
- can taint wine through creation of TCA (trichloroanisole).
- variable rates of oxygen ingress, meaning the same wine ages at different rates depending on the cork.
50
What is ISO Certification?
Who is the certifier?
What is its purpose?
- External verification of quality standards as set by the ISO (International Organization for Standardization.)
- Certification itself is carried out by separate certification bodies (third parties).
- Purpose = assurance of quality to all parties down the supply chain (wholesaler =\> retailer =\> consumer)
51
How do glass stoppers work?
What are PROS (2)/CONS (2)?
- glass closure w/a seal formed by a plastic ring.
PROS: - wine can be stored for similar length of time as natural cork.
- attractive look
CONS: - special bottles must be used to ensure a perfect fit.
- as expensive as top-quality cork = usually premium/super-premium wines only.
52
What are disadvantages of shipping wine in bulk (3)?
specific e.g. of where this has been a problem?
- loss of direct relationship with producer
- transfer of business and employment opportunities from producer countries to countries closer to final market
- only viable for larger brands
e. g. in South Africa, shipping wine in bulk to be bottled closer to market has sparked protests complaining about the loss of business and jobs.
53
What are some arguments FOR (3) and AGAINST (2) filtering wines?
FOR: - belief that wine recovers from shock of filtration after some months.
- less chance of faults developing (bacteria/yeasts are removed)
- belief that fruit+terroir of wine are expressed better in properly fined/filtered wine.
AGAINST: - belief that filtering negatively affects wine's character, texture + flavor.
- belief that terroir is stripped away.
54
How does GELATIN work as fining agent (3)?
What are some disadvantages of using it (3)?
- removes phenolics that contribute undesirable color / bitterness / astringency.
- protein extracted from pork
- also removes browning in white wine.
- can easily strip flavor / character from wine if over-used.
- risk of protein haze forming later.
- not suitable for vegetarians.
55
Explain how METATARTARIC ACID works:
Ease of use / Considerations (3)?
- compound that prevents growth of potassium bitartrate + calcium tartrate crystals.
- quick and easy process
- compound is unstable = effect is lost over time esp. if wines are stored at warm temps.
- tends to be more effective on reds than whites/rosés
56
What are the differences between cleaning, sanitization and sterilization?
- cleaning: removal of surface dirt
- sanitation: **reduction** of unwanted organisms, typically w/ water +detergent
- sterilization: **elimination** of unwanted organisms, typically w/high strength alcohol/steam.
57
How is the fault of oxidation caused in wines (2)?
How does it affect the wine (3)?
- caused by excessive exposure to oxygen either during winemaking process or due to faulty bottling/packaging.
- wine becomes brown in color, loses primary fruit notes, gains a vinegary smell.
58
What is a Technical Cork?
What are 3 different examples and how are they made?
A closure made from pieces of cork that have been subjected to a manufacturing process.
1) Agglomerated cork; cheapest option made from cork granules glued together, only suitable for inexpensive wines for short-term consumption.
2) one-plus-one cork; central section is agglomerated cork, finished with natural cork on both ends.
3) Diam corks; made from traditional cork that has been broken down into particles, cleaned and put back together using food-grade binding agents.
59
What are the components of a screwcap made with?
What is an issue that has come up in regards to screwcap usage, and how are winemakers responding to it?
- Aluminum closure w/ a seal made from either impermeable tin or low-permeability Saran.
- Issue of reductive odors (rotten egg, onion) forming from near impenetrability to oxygen.
- To combat this, winemakers are adapting the final wine to have a slightly lower level SO2.
60
Why can a wine be cloudy/hazy (2)?
What are some remedies for cloudiness/hazes? (3)
Growth of yeast/bacteria / inadequate or poor filtering.
1) better hygiene in winery
2) chemical analysis
3) filtering
61
Why is a formal system of traceability necessary for a wine company to have (2)?
1) to respond/investigate complaints about wine, which can come from any point in the supply chain.
2) to improve practice so similar problems don't arise in the future.
62
What are pouches similar too?
What sizes do they come in?
- Similar to the bags housed within bag-in-box packaging.
- Available in larger (1.5L) and single-serve sizes.
63
What are options for tartrate stability (6)?
1) cold stabilization
2) contact process
3) electrodialysis
4) ion exchange
5) carboxymethylcellulose (CMC)
6) metatartaric acid
64
Outline the actions that will be taken in the final months of a wine before packaging:
1) 4 months - 8 weeks ahead (2)
2) 8 weeks
3) 6 weeks
4) 4-6 weeks
5) 4 weeks
6) 1-2 weeks
7) 72-48 hours
8) 24 hours
9) Bottling day
10) During bottling
1) Assemble final blend / Full chemical analysis – alcohol, residual sugar, free SO2, etc.
2) Final adjustments: alcohol, acidity, tannins if desired
3) Protein stability trial and if necessary fine with bentonite
4) Test for tartrate stability and, if necessary, treat
5) Check protein stability and tartrate stability again, treat as necessary
6) Add sweetening agents e.g. grape concentrate, if using (for mouth feel and finish)
7) Test filterability of wine
8) Adjust free SO2
9) Adjust dissolved oxygen and CO2
10) Check dissolved oxygen (to ensure no pickup) and SO2 levels regularly and keep sample of bottle wines for quality assurance purposes
65
What are some methods of transport for shipping large amounts of wine?
- Road+Rail for containers (24K Liters), e.g. from southern Europe to markets in northern Europe.
- Container ships to carry wine from Australia / NZ / S. Africa / Chile / Argentina to final markets and bottling plants in the northern hemisphere.
66
Free SO2 is the part that contains ____ SO2.
The ____ the wine's pH, the more \_\_\_\_SO2 is present.
Therefore, wines with \_\_\_\_pH require ____ amounts of SO2.
- molecular.
- lower / molecular.
- lower / lower.
67
What are Synthetic closures?
What are the 2 main types?
What are some drawbacks (2)?
aka Plastic corks, these are made of food-grade plastic w/a silicone coating.
Molded closures; cheap, rigid and hard to re-insert.
Extruded closures; more elastic, made w/external firm layer of plastic covering a plastic foam.
Limited protection from oxygen ingress = only suitable for early-consumption wines.
"Flavor Scalping"; plastic absorbs flavor molecules.
68
What are advantages of shipping wine in bulk? (5)
- more environmentally friendly and cheaper than shipping in bottle (24-25K bottles vs 9-10K)
- less fluctuation of temperature
- strict quality control (both at filling and emptying of container)
- wine can be adjusted at point of bottling, closer to consumer
- shelf life is therefore extended b/c it is calculated from time of bottling vs. time of production.
69
What is cork taint?
What is it caused by?
Wine fault that causes wine to smell of moldy, wet cardboard and lose fruit character.
Caused by TCA (2,4,6-trichloroanisole) infecting cork and then tainting wine.
70
What are disadvantages of shipping wine in bottle? (4)
- smaller amount per container = higher cost
- financial and environmental costs from weight of bottles
- potential damage to wine due to high fluctuating temperatures
- shorter shelf life of inexpensive wine because bottled earlier
71
What is Light Strike?
What causes it to occur (2)?
How can it be prevented (3)?
A fault caused by UV radiation reacting w/wine compounds to form volatile sulfur compounds = dirty drain odors.
Occurs w/wines left in direct sunlight, near fluorescent lights.
Storing wine away from direct sunlight, away from fluorescent, using darker (green, brown glass)
72
How is the cork industry working to reduce cork taint (5)?
1) coming up with alternative closures
2) cleaning corks with steam extraction
3) more rigorous quality control during production
4) creating corks from recomposed cork particles that have been cleaned + reconsituted.
5) introducing a barrier btw/cork and wine; impermeable membrane that gives the end of the cork a wrinked appearance.
73
What is centrifugation?
What are its major advantages (2)?
What types of wineries use it?
- Rapid process that spins the wine at high rotational speed to clarify it.
- Replaces depth filtration + allows early bottling.
- V. effective w/wines that have a lot of suspended matter.
- Usually only practised by high-volume wineries that can absorb the cost of the machine
74
What is fining (3)?
What is it useful for (3)?
- procedure in which a fining agent (e.g. egg white) is added to a wine to speed up the process of the precipitation of suspended material.
- fining agent must have opposite charge from wine colloid
--\> they attract each other and form solids large enough to be removed.
- especially useful in removing microscopic particles that are too small to be removed by filtering.
- clarifies wine
- stabalizes wine against formation of hazes later in the bottle.
75
What are the advantages of using glass bottles? (4)
1) inert material (best for aging)
2) can be delivered in near sterile condition
3) inexpensive to manufacture, comes in range of colours
4) 100% recyclable
76
What are the PROS (2) and CONS (2) of Sheet Filtration?
PRO: - Cost of filter sheets is low
- Customizable; sheets of different grades can remove different levels of material
CON: - Initial investment is high (v. robust frame require to withstand pressure)
- Trained personnel must operate them = $$$
77
What are 3 examples of finishing adjustments?
1) adjusting level of SO2 (making sure within legal limits)
2) reducing dissolved oxygen (to extend shelf life)
3) adding CO2 (adding a "spritz" before bottling)
78
How does a winery maintain a consistent system of traceability (4)?
- each consignment of wine receives a lot # (requirement in EU / many other markets).
- lot # enables company to trace where the grapes came from, what additives were used and what processes the wine went through.
- records kept of activities at every step.
- library of samples of batches are kept so they can be compared to faulty bottles and investigated.
79
What are tartrates?
What chemicals make them up (2)
Why are they regarded as undesirable?
Harmless deposits of crystals that form in finished wine.
Principally potassium bitartrate / sometimes calcium tartrate.
Less knowledgable customers regard these as a fault.
80
Why are most present day wines technically fault free (7)?
Because of the care taken at every stage of the production process:
- sorting out moldy/damaged fruit
- exclusion of oxygen at key points.
- temp. control
- scrupulous hygiene.
- stabalization
- SO2
- fining+filtering
81
Why would a winemaker want to reduce the amount of dissolved oxygen in a finished wine?
What method can solve this?
AKA?
- dissolved oxygen speeds up aging / decreases shelf-life of wine.
- can be removed by flushing the wine with an inert gas to remove it.
- This is called "sparging"
82
Explain Sedimentation in 3 steps:
Wine is allowed to stand in cool cellar conditions
--\> higher density particles will form sediment at the bottom of the container
--\> wine can be racked off, leaving sediment behind
83
When is reduction considered a fault?
What causes it?
What can reduce threat of reduction (2)?
Considered a fault when sulfur-like aromas are strong enough to emulate onion/rotten egg aromas.
Caused by lack of yeast nutrients e.g. nitrogen, which causes yeast stress / exclusion of oxygen in closed vessels, esp during lees aging.
1) ensuring yeast has efficient nutrients and oxygen
2) ensuring the must is at adequate temperatures
84
What are different viewpoints on Brettanomyces being a fault?
What promotes its growth (3)?
- at low levels, some tasters enjoy the spicy, animal, farmyard smells it imparts.
- at high levels, when the flavors dominate/eliminate fruit flavors it is considered a fault.
Caused by lack of SO2 to kill spoilage yeast / unhygienic conditions / lack of cleaning of wooden barrels
85
What are advantages of plastic bottles (5)?
When is it most appropriate as a packaging option (4)?
- range of sizes available (standard, single serve RTD (ready to drink)
- tough, inexpensive, recyclable, light.
Best-suited for wines w/limited shelf life, for quick consumption, informal settings, in situations where breakage is a hazard (planes, concert venues)
86
What are some examples of fining agents that remove phenolics that contribute undesirable colour/bitterness (6)?
1) egg white
2) gelatin
3) casein
4) isinglass
5) Vegetable protein products (from potatoes / legumes)
6) PVPP
87
How does the length of a cork influence its efficacy?
Shorter corks = cheaper, used for inexpensive wines meant for early consumption.
Longer corks = better quality, more expensive, meant for higher-priced wines that will be aged in bottle.
88
How does PVPP work as fining agent (4)?
- polyvinylpolypyrrolidone
- removes phenolics that contribute undesirable colors + bitterness.
- insoluble plastic in powder form
- removes browning + astringency from oxidized white wine.
89
What do winemakers do before using fining agents (2)?
Why (2)?
- conduct lab trials to ensure that the min. effective amount is used.
- then fined sample is compared to original.
WHY:- many fining agents remove positive compounds from wine.
- sometimes wine is made less stable when too much is added.
90
Explain how ION EXCHANGE works:
Consideration?
- replaces potassium+calcium ions w/hydrogen / sodium ions, which will not drop out of solution.
- not allowed in some regions due to sodium's effect on health, though levels are well below legal limit.
91
What are the PROS (2) and CONS of Depth Filtration?
PROS: - can cope w/fluid w/many particles in it (e.g. lees)
- does not block easily
CONS: - not absolutely reliable b/c some particles will work through the filter if used for too long / too much pressure is applied.
92
What are the general amounts of free SO2 found in red/white/sweet wines?
White wine: 25-45 mg/L; lower due to lower pH
Red wine: 30-55mg/L
Sweet wine: 30-60mg/L; higher due to decreased microbial stability in wines w/RS
93
Explain what is happening in the picture below (4):
1) A fining agent is added to an unfiltered wine.
2) The fining agent has an opposite charge from the wine colloid, so they attract each other and form a larger solid.
3) This new solid is heavier and falls to the bottom.
4) These solids can now be removed by racking/filtration.
94
What is stabilization?
3 e.gs?
Refers to several winemaking interventions which prevent undersired effects on finished wine.
e.g. Protein stability / Tartrate stability / Microbiological stability
95
What are the disadvantages of using glass bottles? (5)
1) high carbon footprint because of heat needed to manufacture
2) heavy to transport (contributes to footprint)
3) fragile
4) rigid -- once open, subject to rapid oxidation
5) clear bottles are subject to light strike
96
Why is it necessary to use a fining agent to remove unstable proteins from white/rosé wines but not reds (2)?
- the proteins bind w/tannins in red wine, so will preciptate naturally and be removed with racking.
- in whites/rosés = proteins agglomerate into a visible haze =\> fault in most wines.
97
Explain the mechanics of Brick packaging:
Where are wines packaged this way most successful?
The Brick is made of paper card w/plastic + aluminum foil layers that exclude oxygen + light.
Does best w/wines at a lower price points in markets where price is a major driver (e.g. Germany)
98
Why would a winemaker choose sedimentation / racking as a method of clarification over others (2)?
Why not (2)?
FOR: - gentlest form of clarification.
- some winemakers believe that sedimentation retains textures/flavors that are lost by fining/filtering.
- if wine is barrel-aged, sedimentation happens naturally.
ANTI - $$$ for labor
- racking takes time; high-volume wine production will want to accelerate speed of processing.
99
What is a side effect of using a rotary vacuum filter w/DE?
How can this be avoided, if so desired?
- it is an oxidative process (drum is exposed to air)
- to avoid this, winemakers can use enclosed DE filters which can be flushed w/inert gas, e.g. nitrogen.
100
What are some factors that influence the levels of SO2 in finished wines (4)?
- winemaking approach (e.g. "natural" / Biodynamic)
- wine style (red/white/sweet)
- pH
- intended drinking period (early drinking vs. cellar aging)
101
How does a cross-flow filter work?
What are PROS (3) and CONS (1) of using one?
- allows wine to pass through filter while uniquely cleaning surface of filter as it works
PROS: - can filter wine with high load of particles very quickly
- does not clog as quickly as membrane filters.
- no replacement sheets / cartridges / DE to buy or dispose of.
CONS: - machinery is expensive; only suitable for large/well-funded wineries.
102
What are some reasons to ensure a wine is microbiologically stable (3)?
What can be done to address these problems (3)?
- to prevent re-fermentation from happening in wines w/RS. =\> filter out yeasts / add sorbic acid+SO2, which inhibits yeast growth.
- to prevent MLF from restarting in wines w/lactic acid bacteria. =\> ensure MLF has been fully completed / filter out bacteria
- to remove undesired spoilage yeasts e.g. brett. =\> treat w/DMDC (Velcorin) before bottling.
