Free Flashcards DipWSET D1: Wine Production – 10/Finishing

1. Amount of dissolved oxygen in the wine;
2. Oxygen in the head space (usually the greatest contributor);
3. Amount of oxygen in the closure;
4. Oxygen transmission rate (OTR) of the cork or closure

• Slightly higher SO₂ level to counter oxidation;
• Low dissolved oxygen level;
• No head space;
• Low carbon dioxide to avoid the bag from bulging or bursting

Food-grade plastic with a silicone coating

[q] Name two hazards that come with using synthetic closures

[a]

1. Limited protection from oxygen ingress;
2. Flavor scalping (the plastic absorbs some of the flavor molecules in the wine)

[q]

The seal in screwcaps that protects wine from oxygen can be made of two materials.

What are those materials, and how permeable/impermeable are they?

[a]

• Tin, which is impermeable to oxygen;
• Saran, which is a form of plastic with low permeability to oxygen

[q]

How do winemakers avoid their wine developing reductiveness after bottling their wine under screwcap?

[a]  

They use slightly lower levels of SO₂

[q]

Glass stoppers are really only suitable for:

• Inexpensive wines
• Mid-priced wines
• Premium and super-premium wines

[a]

• Premium and super-premium wines

[q]

Most wines that are based on fresh, fruity flavors are best consumed:

• within a year of bottling as maturing results in a loss of primary fruit flavors
• after several years because they’re not at their best immediately after bottling

[a]

Within a year of bottling as maturing results in a loss of primary fruit flavors

[q] Describe the ideal environment for bottle maturation.

[a]

The wine should rest undisturbed in a cool dark place with a constant temperature, around 10–15°C / 50–59°F. There should also be constant humidity.

If sealed with a cork, the bottles should rest lying on their sides, so the cork stays moist and keeps the bottle sealed (if the cork dries out, the wine will oxidize)

[q] What are the three hygiene procedures to follow in a winery?

[a]

1. Cleaning
   • this removes surface dirt
2. Sanitation
   • this reduces undesirable organisms to an acceptable level
   • made of water + detergent, another sanitising agent and/or steam
   • this uses ~10 liters of water for every liter of wine produced
3. Sterilization
   • this eliminates unwanted organisms
   • sterilization is done with high strength alcohol or with steam

[q] Briefly explain why HACCP (Hazard Analysis of Critical Control Points) is a common approach used in wineries to assess quality assurance

[a] It’s a process that examines all the potential hazards and everything that could go wrong in the winery so the winery can prevent and correct any issues before they happen

[q]

Why would a wine company seek to have their quality standards to be externally audited by a third party against the standards of the ISO (International Organization for Standardization)?

[a]

To give confidence to all the parties down the supply chain: the wholesaler, the retailers who will sell the wine, and the end consumer

[q]

The EU and many other markets require wines to be assigned lot numbers and to have those lot numbers printed on the wine’s label.

What does having a lot number enable the winery to do in the event of complaints or problems?

[a]

• To trace back:

  • Where the grapes came from;
  • What additives were used;
  • What processes the wine went through;
  • How the wine was transported

[q] What are the two main types of containers used for shipping bulk wine?

[a]

• Flexitank – a single-use, recyclable polyethylene bag that fits into a standard container (more common);
• ISO tank – a stainless steel vessel that can be reused many times that is built to the ISO standard; it may have additional insulation

[q] What is the advantage of shipping wine in bottle as a complete product?

[a]

Everything is controlled by the producer: the wine, the bottling, the labelling and any external packaging

[q] What are the disadvantages of shipping wine in bottle as a complete product?

[a]

1. Less wine can be shipped in one container, so the cost to ship is higher
2. The financial and environmental cost of shipping the weight of glass (as well as the wine)
3. Potential damage/spoilage to the wine due to sometimes high and fluctuating temperatures in transit
4. Potential damage of labels and packaging in transport
5. The shorter shelf life of inexpensive wine because it is bottled earlier than if it were bottled in or close to the final market

[q]

What are the advantages of shipping wine in bulk?

[a]

1. Environmentally friendly and cheaper (containers hold 2-2.5x as much wine as filled bottles, reducing the wine’s carbon footprint)
2. The greater thermal inertia of a whole container filled with wine, so there is less fluctuation of temperature (reducing the risk of oxidation)
3. Strict quality control: chemical analysis can be performed at the filling and emptying of the container
4. The wine can be adjusted at the point of bottling
5. The shelf life of a wine can be extended, which is most relevant for bag-in-box and its relatively short shelf life

[q] What are the disadvantages of shipping wine in bulk?

[a]

1. Loss of the direct relationship with the producer
2. Business and employment opportunities transfer from the producer’s country to that of the final market

[q]

Why is the majority of white wines made with no or minimal skin contact?

[a]

Because the most important aroma and flavor compounds in white grapes are found in the pulp, so skin contact isn’t required for aroma and flavor extraction

[q]

What are two negative effects if a white wine sees excessive skin contact?

[a]

The wine can:

• • Taste bitter
  • Feel coarse on the palate

[q]

[a]

1. If the wine is meant to express delicate, fruity flavors;
2. If the winemaker wants a smooth mouthfeel;
3. If the winemaker wants a light color on the wine;
4. If the fruit was picked under-ripe;
5. If the wine is inexpensive and meant to be drunk very young

[q]

[a]

1. Time;
   • longer time on skins = greater extraction of flavor + tannins
2. Temperature

[q]

How does a cooler temperature affect extraction during skin contact?

[a]

Chilled juice during skin contact (15°C /59°F or below) reduces the rate of extraction of flavors and tannins.

It also:

• allows more control;
• reduces the rate of oxidation and microbial spoilage, including likelihood of spontaneous fermentation

[q]

What are some white grape varieties on which skin contact is most effective?

[a]

Aromatic grape varieties like Riesling, Gewurztraminer, Viognier, Muscat and Sauvignon Blanc

• they have many aroma compounds that can be extracted from the skins;
• aromatic varieties are not often matured in oak, so skin contact is also a way of enhancing texture.

[q] Describe the profile of an ‘orange wine.’

[a]

• Fermented on their skins, usually without temperature control or sulfur additions;
• Notable levels of tannins;
• Main flavors and characteristics are tertiary, e.g. nuts, hay, and dried fruit, which emerge from aromatic and phenolic compounds extracted from the skins;
• Typically dry (though not always)

[q] What are the advantages of using whole-bunch pressing for white grapes?

[a]

1. Reduces the chance of oxidation before and during pressing
   • more so if an inert gas (e.g. nitrogen) is used in the press
2. Very gentle way of pressing grapes
3. Yields juice that is low in solids, tannins and color
4. Stems provide channels for the juice to drain

[q] What are the disadvantages of using whole-bunch pressing for white grapes?

[a]

1. Restricted only to hand-harvested grapes;
2. Whole bunches take up a lot of room in the press;
   • fewer grapes can be loaded for each press cycle;
3. Only really suited for smaller batches of premium wines;
4. Inefficient for grapes that need to be processed quickly and efficiently

[q]

What is the difference between “free run” juice and “press” juice?

[a]

Free run = juice from destemmed grapes that is drained off as soon as the grapes are crushed. It is lowest in solids, tannins, and color, and it’s higher in acidity (low pH). Good for lighter bodied style of wine.

Press juice = juice from the grapes being pressed. The first part of the first pressing is somewhat similar to free run in that solids, tannins, and color are low, but ultimately it has lower sugar and acidity than free run. As pressure is sustained and more is applied for each press fraction, the less like free run the juice becomes. Press juice makes wines with fuller body compared to wines made from free run

[q] What is the hyperoxidation technique, and what does it do?

[a]

[q]

When employing the hyperoxidation technique, how do winemakers remove the compounds that have turned brown?

[a]

[q]

In what other ways does hyperoxidation help winemakers when they make white wines?

Is hyperoxidation typically better suited for neutral or aromatic grape varieties?

[a]

1. Can remove bitter compounds from unripe grape skins, seeds and stems;
2. Can destroy some of the most volatile aroma compounds found in the must;
   • typically better suited to less aromatic grape varieties, e.g. Chardonnay

[q] At what points can clarification occur in winemaking?

[a]

• Between pressing and fermentation;
• After fermentation

[q] What is the aim of clarification?

[a]

To reduce the amount of suspended solids in the must

[q] Winemakers typically aim for the proportion of solids in the must to be somewhere between ___–___%.

[a]

0.5–2%

[q]

What does a higher proportion of solids in a white wine must lend to the finished product?

Wine at what price point is best suited for using this technique?

[a]

[q] What is a risk of having too many solids in white wine must during fermentation?

[a]

Off-flavors developing from reactions between compounds within the solids

• at lower levels, they can smell like reductive sulfur compounds;
• at higher levels, can smell like rotten egg.

[q]

1. Why is it good to have some solids in your must?
2. What is a risk of having low to no solids in your must?

[a]

1. Solids provide nutrients for yeast;
2. Low to no solids can lead to stuck fermentations; these musts also need careful management, and yeast nutrients may need to be added

[q]

What are the four options winemakers have to clarify must?

[a]

1. Sedimentation (simplest form);
2. Flotation;
3. Centrifugation;
4. Clarifying agents.

[q]

Bentonite:

1. How does sedimentation work?

[a]

1. The must is chilled to 4°C / 39°F to reduce oxidation and microbial spoilage, and to avoid spontaneous fermentation;
2. Suspended solids in the must are left to fall over time with gravity

[q]

What does the rate of sedimentation depend on?

How long does sedimentation typically take?

[a]

Size and shape of the vessel

Large, tall vessels = longer sedimentation;
Smaller, shorter vessels = shorter sedimentation.
Sedimentation takes 12-24 hours

[q] What happens to the must and solids after sedimentation?

[a]

[q]

How does flotation work?

[a]

An inert gas (like nitrogen) is bubbled up through the must and as it rises it brings with it solid particles; those particles are then skimmed off.

If oxygen is used as the gas, this is a method of hyperoxidation

[q]

[a]

Speeds up the rate of clarification

[q]

What needs to be added to the must in order for flotation to work?

[a]

Fining agents, which help bind the particles together

[q]

Flotation can be used:

• on both must or wine
• only on must
• only on wine

[a]

Only on must

[q]

Flotation can be used:

• Only as a continuous process
• Only as a batch process
• Either as a continuous or batch process

[a]

Either as a continuous or batch process

[q]

Centrifugation can be used on:

[a]

Wine as well as must

[q]

How does centrifugation work?

[a]

It’s a machine that has a rapidly rotating container which uses centrifugal force to separate solids from liquids

[q]

What are the advantages of centrifugation?

[a]

1. It clarifies must quickly;
2. Can be used continuously, which saves time and money

[q]

What are the disadvantages of centrifugation?

[a]

• Equipment is expensive to buy;
• Used only in wineries that need to process large volumes of must quickly;
• Increases the must’s exposure to oxygen unless the machine is flushed with inert gas

[q]

What is the common clarifying agent added to must which helps break down pectins in the must?

[a]

Pectolytic enzymes

• • They only aid the clarification of must, not wine;
  • They encourage rapid separation between the liquid juice and solids

[q]

White wines ferment at cooler temperatures than red wines, but winemakers can use very cool or slightly warmer fermentation temperatures for their white wines.

What are the benefits of each?

[a]

Very cool fermentation temperatures (~15°C / 59°F) help produce desired fruity, volatile aroma and flavor compounds;

Slightly warmer temperatures (17–25°C / 63–77°F, or higher) promote yeast health and avoid the production of certain esters, e.g. isoamyl acetate (banana). Slightly warmer temperatures are favored for wines that will see oak

[q]

Stainless steel tanks are the vessels of choice when a winemaker is making which style of white wine:

• Fruity, floral whites
• Neutral white wine
• Orange wines

[a]

Fruity, floral whites

[q]

What are the advantages (and one disadvantage) of fermenting in small oak barrels?

[a]

1. 1. More labor intensive due to monitoring several barrels instead of one large vessel, which can drive up costs

      Advantages:

      1. Wines have deeper color, fuller body, more integrated oak-derived aromas;
      2. Small size of barrels increases lees contact, which contributes texture;
      3. Provides more blending options since every barrel will be different.

      Disadvantage:

       – More labor intensive due to monitoring several barrels instead of one large vessel, which can drive up costs

[a]

• Reduction in acidity;
• Increase of pH;
• Increase in microbiological stability;
• Modification to the flavors of wine (butter)

[q] Why is malolactic conversion avoided in certain white wines?

[a]

To preserve the distinctive, primary aromatics of the grape

[q]

What are the aims of aging wine sur lie?

[a]

1. Give the wine more body
2. Soften the mouthfeel
3. Help to stabilize the wine
4. Protect the wine from oxygen

[q]

Lees stirring is also called ___.

[a]

Bâtonnage

[q] What are some of the beneficial effects from bâtonnage?

[a]

• Increases the release of yeast compounds into the wine;
• Introduces oxygen exposure;
  • this increases the effects from the lees and decreases fruity flavors;
  • reduces the development of reductive sulfur compounds and off-aromas

[q]

What are the three main ways of producing wine with residual sugar?

[a]

1. Concentrating the sugar in the grape must;
2. Stopping the fermentation before dryness;
3. Blending a sweetening component into the wine

[q] What are the four methods of concentrating grape must?

[a]

1. Drying grapes on the vine;
2. Drying grapes off the vine;
3. Noble rot;
4. Freezing the grapes

[q]

What happens to grapes when they’re left to dry on the vine?

[a]

1. They shrivel;
   • water is lost by grape transpiration and the sugars concentrate;
2. Flavors develop into very ripe or extra-ripe flavors

[q] What is the benefit of cutting or breaking off a cane of the vine a short time before harvest in order to dry out the grapes that are still attached to that cane?

[a]

1. The grapes shrivel more quickly than they would if they were still attached to the rest of the vine, concentrating the grapes’ sugars, acids and flavors faster;
2. Reduced hang time lowers risk of grey rot;
3. Some grapes will exhibit very high levels of sugar without extra-ripe flavors

[q]

What happens in the process of drying grapes off the vine?

[a]

1. Causes water inside the grapes to evaporate, thereby concentrating the acids, sugars and flavors
2. Speed up drying
3. Avoids the development of grey rot

[q]

What are the conditions needed for Noble Rot to develop?

[a]

Humid, misty mornings followed by sunny, dry afternoons

[q]

How does Botrytis cinerea attack grapes?

What are the distinctive aromas attributed to Noble Rot?

[a]

Damp, humid mornings allow the fungus to develop on the grapes;

The fungus punctures the grape skin, leaving tiny holes;

Warm sunny afternoons slow the development of the rot and cause water to evaporate from the grape, concentrating its sugars, acids and flavors.

[q]

How can Botrytis cinerea go from being Noble Rot to Grey Rot?

[a]

If conditions are too damp, the fungus will develop too fast and split the grapes, encouraging infections

[q]

Grapes affected by Noble Rot are not easy to process in the winery.

What steps do winemakers have to take in order to process these grapes?

[a]

1. Chilling the must;
2. High doses of SO₂;
3. Use inert gases to minimize the oxidation of the must

[q]

What happens to the water in grapes if they’re left to freeze on the vine?

[a]

The water freezes and turns to ice, so when the grapes are picked and pressed this ice stays behind in the press and the sugars of the resulting juice is intensely concentrated

[q] At what temperature can Canadian Icewines be harvested?

[a]

−8°C / 18°F or below

[q]

What are some of the characteristics needed for vines used in Ice Wine production?

[a]

The vines need to:

• Be winter-hardy;
• Produce grapes with resilient skins that give protection from disease;
• Withstand the strain of freeze–thaw cycles

[q] Picking grapes in the autumn and then freezing them at a winery to later be used for sweet wine production is called ____.

[a]

Cryoextraction

[q] What is the most common way of stopping fermentation to create a sweet wine?

[a]

• By chilling the wine to below 10°C /50°F and/or adding a high dose of SO₂to inhibit the yeast
• It is then racked off its sediment and sterile filtered to ensure fermentation does not start again later on

[q]

[a]

Blending in a sweetening component

[q]

What are the most common sweetening components used to make sweet wines?

[a]

1. Sugar
2. Rectified concentrated grape must (RCGM)
3. Unfermented grape juice

[q] What are the benefits of using RCGM as a sweetening component?

[a]

• Neutral in flavor as it’s just the sugar from the grape
• Can use less of it to sweeten wine
• Inexpensive

[q]

Many of the choices involved in red winemaking are focused on the extraction of ____, ____, and ____.

[a]

Anthocyanins, tannins, and flavors from the grape skins

[q] Many of the choices involved in red winemaking are focused on the extraction of ____, ____, and ____.

[a]

Anthocyanins, tannins, and flavors from the grape skins

[q] What four factors affect extraction in red winemaking?

[a]

1. Temperature
   • higher temperatures result in greater extraction;
2. Time on skins
   • the longer the skin contact, the greater the extraction;
3. Cap management
   • the more the skins are mixed through the juice, the greater the extraction;
4. The extraction medium
   • is the solution more water (read: grape must) or more alcoholic (wine)?

[q]

Anthocyanins as single molecules are not that stable. However, when they combine with ___, they become more stable, thereby increasing color stability.

What helps to facilitate this reaction?

[a]

• Tannins
• Oxygen helps facilitate this reaction (this means that processes that encourage oxygen into the wine – barrel aging, microoxygenation – help with color stability)

[q] The broad majority of red wines are made using whole cluster or destemmed berries?

[a]

Destemmed berries

[q]

What is the chief aim of pre-fermentation maceration?

[a]

Extract color and flavor without extracting tannins

[q]

Anthocyanins are soluble in

[a]

Both must and wine

[q]

Tannins are more soluble in

[a]

Alcoholic liquids

[q]

[a]

roughly 4–10°C / 39–50°F

This reduces:

• the rate of oxidation
• microbial spoilage
• spontaneous fermentation

[q]

Cold soaks, or pre-fermentation macerations, usually last about how long?

[a]

3–7 days

[q]

During the 3-7 days of cold soaking, the grapes are punched down and/or the fresh must is pumped over the grapes.

What does this help with?

[a]

• Slower extraction which can be monitored and controlled
• Inhibits the growth of spoilage microbes that need oxygen

[q] Name two maceration techniques that use heat in aiding extraction

[a]

1. Flash détente;
2. Thermovinification

What are the five major cap management techniques?

• The winemaker can change the frequency of mixing and the time spent mixing, determining extraction;
• When the mixing occurs during fermentation the winemaker can influence which compounds are extracted;
• Temperature during mixing can affect which compounds are extracted and to what degree

Why are rotary fermenters so effective at extracting color, flavor, and tannin?

When a winemaker is employing whole bunches in their fermentation, why do they need to ensure the bunches are fully ripe?

2%

[q]

In carbonic maceration, how is that 2% alcohol achieved within the berries (where does it come from)?

What effect does this have on the must?

[a]

Malic acid within the grape is broken down to create ethanol, which reduces malic acid levels lowering the total acidity (and raising the pH) of the must

• the must can see malic acid reductions of up to 50%

[q]

[a]

1. Intensely colored;
2. Low in tannin

[q]

Why isn’t new oak used on wines that have been fermented with carbonic maceration?

[a]

Because the flavors of the oak (vanilla, toast) would interefere with the fruity, low tannin, candy-like flavors of the wine.

Wines made with carbonic maceration also are meant to be drunk within a year of harvest, so it doesn’t make financial sense to use new oak on these wines

[q]

What is the main difference between carbonic maceration and semi-carbonic maceration?

[a]

No CO₂ is added to the tank in semi-carbonic maceration.

In semi-carbonic maceration, the ambient yeasts start to ferment the juice that has been released from the grapes, which have burst under the sheer weight of all the whole bunches. CO₂ is produced from those ambient yeasts metabolizing the sugar in the released juice which fills the tank, and then the remainder of the whole berries/bunches undergo carbonic maceration

[q] If a winemaker uses semi-carbonic maceration but they want to produce a more serious wine with slightly more concentration, body and tannin, what can they do after the semi-carbonic maceration has completed?

[a]

1. Continue alcoholic fermentation on the skins and incorporate punching down or pumping over;
2. Post-fermentation maceration and/or maturation in oak to add complexity

What is the thought behind adding whole berries/bunches to crushed fruit and how that affects the final wine?

When are red wines pressed?

• The barrels impart flavors of the oak (vanilla, clove);
• Barrels provide gentle oxidation:
  • helps soften tannins;
  • helps develop tertiary aromas and flavors that can enhance complexity and quality

[q]

[a]

Blended after they’ve already fermented

[q]

[a]

Cool temperatures (12–16°C / 54–61°F)

[q]

Which vessel is most often used in rosé production?

[a]

• Stainless steel tanks

[q] How do rosés with residual sugar typically get their sweetness?

[a]

1. By stopping the fermentation before it reaches dryness;
2. By blending a sweetening component into the dry rosé

Malolactic conversion in rosé wines is usually: