D1-VINI Quiz on Options for Winemaking

Question 1

Wine is made up of an array of different compounds, some of which come directly from the grapes and others which have been formed during the fermentation process or added as part of other winemaking procedures.These compounds can be roughly split into seven main groups. Identify six of these groups.

Answer 1

1. Water
2. Alcohol
3. Acids
4. Wine aromatics
5. Residual sugars
6. Glycerol
7. Phenolics

Question 2

The EU has a set of classifications for still wines. This means that wines are classified by the use of different labelling terms. Which of the following labelling terms are for DRY wines?

1. Doux
2. Süss
3. Moelleux
4. Halbtrocken
5. Sec
6. Trocken
7. Demi-sec
8. Lieblich

Answer 2

5. Sec
6. Trocken

up to 4g/l RS, or not exceeding 9g/l provided that total acidity expressed as grams of tartaric acid per litre is not more than 2g below RS content. For example, a wine with 9g/l RS can be labelled ‘Sec’ if it has 7g/l total acidity.

Question 3

The EU has a set of classifications for still wines. This means that wines are classified by the use of different labelling terms. Which of the following labelling terms are for MEDIUM DRY wines?

1. Doux
2. Süss
3. Moelleux
4. Halbtrocken
5. Sec
6. Trocken
7. Demi-sec
8. Lieblich

Answer 3

4. Halbtrocken
5. Demi-sec

more than 4g/l and not more than 12g/l RS, or up to 18g/l provided that the total acidity expressed as grams of tartaric acid per litre is not more than 10g below the RS content.

Question 4

The EU has a set of classifications for still wines. This means that wines are classified by the use of different labelling terms. Which of the following labelling terms are for SWEET wines?

1. Doux
2. Süss
3. Moelleux
4. Halbtrocken
5. Sec
6. Trocken
7. Demi-sec
8. Lieblich

Answer 4

1. Doux
2. Süss

at least 45g/l RS.

Question 5

The EU has a set of classifications for still wines. This means that wines are classified by the use of different labelling terms. Which of the following labelling terms are for MEDIUM SWEET wines?

1. Doux
2. Süss
3. Moelleux
4. Halbtrocken
5. Sec
6. Trocken
7. Demi-sec
8. Lieblich

Answer 5

3. Moelleux
4. Lieblich

more than 12g/l and not exceeding 45g/l RS.

Question 6

Wines contain aromatic and non-aromatic compounds which come from four main sources. Name the aromas created by fermentation due to the presence of aroma precursors in grape must?

Answer 6

Thiols and Terpenes

Question 7

Wines contain aromatic and non-aromatic compounds which come from four main sources. Name the Aromas from grapes?

Answer 7

Methoxypyrazines and Rotundone

Question 8

Wines contain aromatic and non-aromatic compounds which come from four main sources. Name other aromas (not from grapes, pre-cursors of fermentation)?

Answer 8

Vanillin and Eucalyptol

Question 9

What is the main aim of the interventions made during modern/conventional winemaking?

Answer 9

The aim is to produce stable wines which reliably show their fruit character and have no faults.

Question 10

In organic wine production in the EU, is the addition of SO2 (Potassium metabisulfite) to wines to stabilise them permitted?

Answer 10

Yes, but only in regulated quantities

Question 11

In the USA, is the addition of SO2 (Potassium metabisulfite) to wines to stabilise them permitted?

Answer 11

No

Question 12

In the USA, the amount of naturally-occurring SO2 must be below how much mg/l?

Answer 12

10 mg/l

Question 13

Exposure to oxygen can create unwanted aromas in wines. Name an aroma that is often considered an unwanted aroma compound as a result of oxidation?

Answer 13

Acetaldehyde

Question 14

Exposure to oxygen can create unwanted aromas in wines. Name an aroma that is often considered an unwanted aroma compound as a result of oxidation?

Answer 14

Acetaldehyde

Acetaldehyde can give nutty, cooked apple aromas, which may be unwelcome when trying to produce a fresh, fruity wine style

Question 15

If vessels are left unfilled, there is a risk wine will be exposed to oxygen. What is the word for the headspace of air between the wine and the top of vessel?

Answer 15

Ullage

Vessels containing wine must be topped up regularly to avoid ullage. Ullage is especially common in wooden vessels due to evaporation.

Question 16

Grape growers may choose to transport grapes to the winery in small crates or large hoppers/bins. SO2 (Potassium metabisulfite) is often used at the point of transportation for grapes in small crates to avoid microbial spoilage and minimise oxygen contact. True or false?

Answer 16

False

Question 17

Grape growers may choose to transport grapes to the winery in small crates or large hoppers/bins. SO2 (Potassium metabisulfite) is often used at the point of transportation for grapes in small crates to avoid microbial spoilage and minimise oxygen contact. True or false?

Answer 17

False

The grapes in the large hoppers/bins are more at risk of getting crushed, therefore exposing them to oxidation and potentially microbial spoilage.

Question 18

Briefly describe the options that are available to a winemaker when it comes to sorting the grapes for quality wines. How might these options differ to those used on inexpensive wines?

Answer 18

The options for the winemaker are as follows:
Prior to harvest, any diseased, damaged and unripe fruit can be removed by hand in the vineyard or at harvest time, if picked by hand.
On arrival in the winery sorting the grapes on a table or conveyor table that vibrates can be carried out by hand.
Optical sorting has a high cost but can be carried out either on a machine harvester or in the cellar. The criteria for the grapes are set by the winemaker and the machine scans the berries, rejecting any berries that do not fit the criteria.
Sorting is generally only carried out on quality wines as it is expensive. If sorting is carried out on inexpensive wines it may be at harvest time and only if the grapes are handpicked.

Question 19

What type of press would be most appropriate for making high quality wines?
(And name other type of presses available in winemaking)

Answer 19

Pneumatic press
(Continuous press, Horizontal screw press)

Pneumatic presses can be programmed to exert different amounts of pressure, and the amount of time the skins spend in contact with the juice can be altered. Oxidation can be managed more efficiently by the use of inert gases before pressing.

Question 20

The process of enrichment usually takes place before or during fermentation, and the aim is to increase the alcoholic content of the final wine. List 4 forms of enrichment.

Answer 20

1. Vacuum evaporation
2. Cryoextraction
3. Reverse osmosis
4. Chaptalisation (addition of dry sugar)
5. Addition of rectified concentrated grape must (RCGM)

Question 21

Grapes (particularly those grown in hot climates) often dramatically drop in acidity when ripening. Different acids are frequently added during processing to raise the acidity levels.
What acid is not permitted to be used for the purposes of acidification in the EU?

Answer 21

Citric acid

Question 22

In contrast to hot climates, the grapes grown in cold climates often contain HIGH or LOW levels of acidity?
This often occurs when grapes have to be picked BEFORE or AFTER they are fully ripe due to poor weather?

Answer 22

High

Before

Question 23

From what can Wine makers choose to deacidify?

Answer 23

1. Calcium Carbonate
2. both of these methods deacidify by forming tartrates in the wine.

Question 24

What is a more modern version that requires considerable investment in deacidifying?

Answer 24

Ion Exchange

Question 25

What is the term for the cost-effective method of exposing wine to oxygen by bubbling oxygen through the wine?

Answer 25

MOx, Micro Oxygenation

Question 26

From what can Wine makers choose to deacidify?

Answer 26

1. Calcium Carbonate
2. Potassium Carbonate
   both of these methods deacidify by forming tartrates in the wine.

Question 27

Specifically for what processes is ‘blending’ often used in winemaking?

Answer 27

Blending grapes from different vessels together
Blending grapes from different vintages together
Blending grapes/must that have been treated differently in the winery together
Blending grapes (from different locations vineyards, regions or countries) together
Blending different grape varieties together
Blending the grapes/must from different grape growers together

Question 28

What is the term for the cost-effective method of exposing wine to oxygen by bubbling oxygen through the wine?

Answer 28

MOx, Micro Oxygenation

Micro-oxygenation is generally carried out in stainless steel tanks for a number of months post alcoholic fermentation. Initially, micro-oxygenation was generally used on inexpensive and mid-priced wines; however, a growing number of wineries producing premium and super-premium wines are using the technique.

Question 29

Wines are often matured in stable conditions to control the rate of oxidation. Briefly describe how a winemaker may moderate these conditions. Remember to include details on the optimal conditions for maturation and the adverse effect experienced if these conditions are altered.

Answer 29

Temperature plays a key role in the rate of oxidation. The recommended temperature for white wine maturation is 8-12ºC (46-54ºF) and for red wines 12-16ºC (54-61ºF). These cooler temperatures ensure the rate of oxidation is slow, constant and stable which slows down the maturation rate. With warmer temperatures the rate of oxidation increases which leads to undesirable aromas and flavour profiles in the wine. If wines are matured in barrel, humidity is a key factor and should be kept above 70% to control the rate of evaporation. Increased evaporation rates affect the volume of wine in barrel.

Question 30

Using bullet points, briefly detail the basic production processes which are usually undertaken when making an oak barrel intended for wine maturation. Give details on why these production processes are completed and what effect they have on the wine.

Answer 30

Depending on the origin of the oak, the process of making the staves is very different. For American oak, the wood is sawn which is a cheaper process as more staves can be produced from a log; for European oak, the staves are split.
The staves need to be seasoned, preferably outside, to reduce humidity levels, reduce the bitter flavours and increase some desired aroma compounds (e.g. cloves) in the wood.
The staves are then heated so they can be bent into shape which also impacts the tannin and aroma compounds in the oak. The temperature and length of ‘toasting’, as the heating process is referred to, will vary from light-, medium- or heavy-toasted.
Aromas of spice, caramel, roasted nuts, char and smoke are imparted from the ‘toasting’ process. The level of toasting will impart more or less of these aromas to a wine.

Question 31

What the the term for the process when the yeast cells will very slowly die post-fermentation and start to break down?

Answer 31

Autolysis

Wine is often matured on these dead yeast cells since thy contribute flavours, body and texture to the wine.

Question 32

Fining speeds up the process of the precipitation of suspended material in the wine with the use of a fining agent. There are three categories of common fining agents:

1. those that remove unstable proteins
2. those that remove phenolics that contribute undesirable colour and bitterness
3. those that remove colour and off-odours.

Name the one that removes brown colours and some off-odours. Over-fining can easily remove desirable aromas and flavours.

Answer 32

Charcoal

Question 33

Explain the seven main reasons for blending wines. A winemaker may choose to blend for more than one of these reasons; give brief details on why each of the reasons may be required.

Answer 33

Balance can be many things in a wine including acidity i.e. blending high acid grapes with lower acid grapes, blending high sugar grapes with lower sugar grapes, blending different grape varieties that add different aromas and characteristics to the overall wine i.e. Cabernet Sauvignon blended with Merlot.
Consistency is key for certain wine styles i.e Sherry and non-vintage Champagne but also for inexpensive large volume still wines. The consumer wants a guarantee of quality and consistency of flavour when they buy these wine styles; vintage variation is not an option.
Style can be tied in with consistency, certain wine styles have a perceived style which is expected each year, irrespective of vintage variation.
Complexity can be increased by blending different varietals and different wines that may have been treated differently in the cellar, increasing the range of flavours in the finished wine.
Minimising faults is only when the fault is minimal to start with i.e. higher than accepted levels of volatile acidity (VA) blended with a wine with no perceived VA.
Volume can be increased by blending with grapes, must or wine that has been bought in from another producer.
Price can be maintained by blending more expensive varietals with less expensive varietals, Chardonnay has a higher market value and will get more money if sold as such even if it is blended with a lesser (inexpensive) grape variety like Semillon.

Question 34

Fining speeds up the process of the precipitation of suspended material in the wine with the use of a fining agent. There are three categories of common fining agents:

1. those that remove unstable proteins
2. those that remove phenolics that contribute undesirable colour and bitterness
3. those that remove colour and off-odours.

Name the one that Clarifies white wines, giving them a bright appearance. Can form a protein haze and produce a fishy smell if overused.

Answer 34

Isinglass

Question 35

Fining speeds up the process of the precipitation of suspended material in the wine with the use of a fining agent. There are three categories of common fining agents:

1. those that remove unstable proteins
2. those that remove phenolics that contribute undesirable colour and bitterness
3. those that remove colour and off-odours.

Name the one that Removes bitterness and astringency in red wine and browning in white wine pressings. Can strip flavour and character, and create protein haze forming later.

Answer 35

Gelatin

Question 36

Filtration is the most common way of clarifying wine. The wine is passed through a filter medium to eliminate the solids in the wine.

What is the technique that Uses pure, inert silica also known as Kieselguhr. Comes in a range of particle sizes, so can remove large or small yeast particles. Must be disposed of responsibly, which carries a cost.

Answer 36

Diatomaceous earth

Question 37

Filtration is the most common way of clarifying wine. The wine is passed through a filter medium to eliminate the solids in the wine.

What is the technique that catch particles that will not go through the pore size of the filter, which are often smaller than 1 micron. For the same reason, wine must be pre-filtered first to avoid blockage. The initial investment is small, but the cartridges are expensive. Often done just pre-bottling.

Answer 37

Membrane filters,

also called cartridge filters.

Question 38

Filtration is the most common way of clarifying wine. The wine is passed through a filter medium to eliminate the solids in the wine.

What is the technique where the wine is passed through layers of filtering material. Requires investment initially but the cost of upkeep is low.

Answer 38

Sheet filters,

Also known as ‘plate and frame’ or ‘pad’ filters.

Question 39

Filtration is the most common way of clarifying wine. The wine is passed through a filter medium to eliminate the solids in the wine.

What is the technique where Wine passes through the filter while uniquely cleaning the surface of the filter as it works. Solid particles cannot pass through the filter. No parts or equipment need to be replaced, but the machinery is expensive.

Answer 39

Cross-flow filters,

Also known as tangential filters.

Question 40

Tartrates are deposits of crystals, usually formed from potassium bitartrate and sometimes calcium tartrate. Although these crystals are harmless they are often regarded as a fault. Therefore, many wineries try and prevent them, name the following method:

This process uses a charged membrane to remove selected ions. It removes both potassium and calcium ions and, to a smaller extent, tartrate ions.

Answer 40

Electrodialysis

Question 41

Tartrates are deposits of crystals, usually formed from potassium bitartrate and sometimes calcium tartrate. Although these crystals are harmless they are often regarded as a fault. Therefore, many wineries try and prevent them, name the following method:

This process does not remove tartrates, but replaces potassium and calcium ions with hydrogen or sodium ions (as they will not drop out of solution).

Answer 41

Ion exchange

Question 42

Tartrates are deposits of crystals, usually formed from potassium bitartrate and sometimes calcium tartrate. Although these crystals are harmless they are often regarded as a fault. Therefore, many wineries try and prevent them, name the following method:

Potassium bitartrate is added to the wine and speeds up the start of the crystallisation process. Wine is usually cooled to around 0°C (32°F) and after one or two hours the resulting crystals are filtered out.

Answer 42

Contact process

This is a quicker, continuous, more reliable and cheaper method

Question 43

Tartrates are deposits of crystals, usually formed from potassium bitartrate and sometimes calcium tartrate. Although these crystals are harmless they are often regarded as a fault. Therefore, many wineries try and prevent them, name the following method:

The wine is held at -4°C; this causes the tartrates to form before bottling so they can be filtered out.

Answer 43

Cold stabilisation

This process only removes the more common potassium bitartrate, not calcium tartrate.

Question 44

For how many days is the wine held at -4°C in Cold stabilisation?

Answer 44

8 days

Question 45

What must be removed by fining before cold stabilisation as they could prevent the crystals from forming at this stage?

Answer 45

Colloids

Question 46

What is added to the wine and speeds up the start of the crystallisation process in the contact process?

Answer 46

Potassium bitartrate

Question 47

Tartrates are deposits of crystals, usually formed from potassium bitartrate and sometimes calcium tartrate. Although these crystals are harmless they are often regarded as a fault. Therefore, many wineries try and prevent them, name the following method:

This cellulose is extracted from wood and prevents tartrates from developing to a visible size.

Answer 47

Carboxymethylcellulose (CMC)

It is much cheaper than chilling.

Question 48

On what type of wines is the Carboxymethylcellulose (CMC) process used and on what wines not.

Answer 48

Often used on inexpensive White and Rosés wines, but is not suitable for Red wines, ‘as it reacts with tannins (rendering it ineffective) and causes haze.’

Question 49

Tartrates are deposits of crystals, usually formed from potassium bitartrate and sometimes calcium tartrate. Although these crystals are harmless they are often regarded as a fault. Therefore, many wineries try and prevent them, name the following method:

Adding this compound prevents the growth of potassium bitartrate and calcium tartrate crystals. However, the compound is unstable, and its positive effect is lost over time, especially when wine is stored at WHAT temperatures.

Answer 49

Metatartaric Acid

High temperatures

Question 50

The vast majority of wine sold is fault-free due to enhanced production processes in the winery. However, they do still occur. What fault is briefly described by:

Wine has a pungent smell of nail varnish and/or vinegar.

Answer 50

Volatile acidity

Question 51

The vast majority of wine sold is fault-free due to enhanced production processes in the winery. However, they do still occur. What fault is briefly described by:

Wine has a mouldy, wet cardboard smell, which also reduces the fruit character and finishes short on the palate.

Answer 51

Cork taint

Question 52

The vast majority of wine sold is fault-free due to enhanced production processes in the winery. However, they do still occur. What fault is briefly described by:

Wine has sulfur-like odours similar to onion or rotten eggs.

Answer 52

Reduction

Question 53

The vast majority of wine sold is fault-free due to enhanced production processes in the winery. However, they do still occur. What fault is briefly described by:

Formation of colourless or white crystals in the bottom of bottle that can be mistaken for fragments of glass.

Answer 53

Tartrates

Question 54

The vast majority of wine sold is fault-free due to enhanced production processes in the winery. However, they do still occur. What fault is briefly described by:

Visible bubbles or spritz in wine, accompanied by cloudiness.

Answer 54

Re-fermentation in bottle

Question 55

The vast majority of wine sold is fault-free due to enhanced production processes in the winery. However, they do still occur. What fault is briefly described by:

Wine can smell like dirty drains.

Answer 55

Light-strike

Question 56

The vast majority of wine sold is fault-free due to enhanced production processes in the winery. However, they do still occur. What fault is briefly described by:

Wine can have a range of off-aromas from animal, sticking plaster or farmyard smells.

Answer 56

Brettanomyces

Question 57

The vast majority of wine sold is fault-free due to enhanced production processes in the winery. However, they do still occur. What fault is briefly described by:

The wine is prematurely brown in colour, with a loss of primary fruit and caramel aromas.

Answer 57

Oxidation

Question 58

Briefly describe the optimum conditions for maturing premium German Riesling. Make sure you cover the following areas and describe why other options have not been chosen:
Packaging/closures
Effect of oxidation
Storage and storage conditions

Answer 58

This wine will develop positively in bottle for many years, so the ingress of oxygen needs to be slow and controlled. Glass will be the choice of packaging as they are impermeable. The choice of closure will be assessed based on its oxygen transmission rate (OTR); different closures including natural/technical corks and screwcaps, have different rates. The most likely choice will be a high-quality cork allowing a slow ingress of oxygen over a period. This small amount of oxygen will have a positive impact on the aroma and flavour profile of the wine.
The recommended environment for ageing wine in bottle is a cool dark room with a constant temperature of between 10-15ºC/50-59ºF and humidity levels of approximately 70%. The wine bottles should be stored on their sides to protect the corks from drying out.