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Wine Production > 15. Finishing and Packaging > Flashcards

15. Finishing and Packaging Flashcards

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1
Q

Getting your wine ready for bottling day

What actions are done between 4-8 weeks bottling?

A
  • Assemble final blend
  • Full chemical analysis: alcohol, RS, free SO2 etc
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2
Q

Getting your wine ready for bottling day

What actions are done around 8 weeks before bottling day?

A

Final adjustments: alcohol, acidity, tannins if desired

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3
Q

Getting your wine ready for bottling day

What actions are done around 6 weeks before bottling day?

A

Protein stability trial and if necessary fine with bentonite

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4
Q

Getting your wine ready for bottling day

What actions are done between 4-6 weeks before bottling day?

A

Test for tartrate stability and, if necessary, treat

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5
Q

Getting your wine ready for bottling day

What actions are done around 4 weeks before bottling day?

A

Check protein stability and tartrate stability again, treat as necessary

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6
Q

Getting your wine ready for bottling day

What actions are done around 1-2 weeks before bottling day?

A

Add sweetening agents (eg RCGM) if using

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7
Q

Getting your wine ready for bottling day

What actions are done 72-48 hours before bottling?

A

Test filterability of the wine

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8
Q

Getting your wine ready for bottling day

What actions are done around 24 hours before bottling?

A

Adjust free SO2

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9
Q

Getting your wine ready for bottling day

What actions are done on bottling day?

A

Adjust dissolved oxygen and CO2

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10
Q

Getting your wine ready for bottling day

What actions need to be done during bottling?

A

Check dissolved oxygen (to ensure no pickup) and SO2 levels regularly and keep samples of bottled wines for quality assurance purposes

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11
Q

What is meant by sedimentation in post-fermentation clarification?

A

If the wine is stored in cool cellar conditions, suspended matter will gradually fall over time and form a sediment at the bottom of the container.
The wine can then be racked off, leaving the sediment behind.

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12
Q

What influences the number of rackings required to remove sedimentation?

A
  • The shape and size of the container
  • The volume of wine
  • The available labour
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13
Q

Why do some producers choose only sedimentation to clarify their wine?

A

Some winemakers believe that clarification by sedimentation avoids the potential loss of texture and flavour that may occur if the wine is fined and filtered.

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14
Q

What are the costs associated with sedimentation as a clarification method?

A
  • Labour
  • Sedimentation takes time, prolonging the time before the wine can be bottled and released. However if the wine is to be barrel aged, then sedimentation happens during the barrel maturation process.
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15
Q

What is centrifugation?

A

This is a rapid process that spins the wine at high speed to clarify it. It can replace depth filtration and allow early bottling. It is very effective with wines with a lot of matter in suspension.

It is only practised in high-volume wineries to spread the considerable cost of buying the machine.

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16
Q

Name the three methods used to clarify the wine post-fermentation.

A
  • Sedimentation
  • Centriguation
  • Fining

Producers typically use a combination of these methods, however some premium producers will only use sedimentation and racking.

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17
Q

What is fining?

A

Fining is a procedure in which a fining agent (protein or mineral origin) is added to speed up the process of the precipitation of suspended material in the wine.
Fining removes a small proportion of unstable colloids (microscopic particles too small to be removed by filtering) from the wine.

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18
Q

What is the difference between fining and filtration?

A

Fining is the addition of a fining agent to speed up the precipitation of suspended material in the wine. It can remove a portion of unstable colloids from the wine (where filtering cannot). Followed by racking.
Filtration is a physical separation technique used to eliminate solids from a suspension by passing it through a filter medium consisting of porous layers that trap solid particles, thus making the liquid clear.

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19
Q

Why do winemakers use fining as a technique to clarify their wines?

A

It helps to clarify the wine and to stabilise it against the formation of hazes later in the bottle.

Many fining agents are able to offer solutions to other problems, such as the removal of harsh tannins in red wines or browning in white wines.

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20
Q

What is an essential step before adding fining agents to the wine? Why?

A
  • Winemakers conduct laboratory trials before using fining agents to ensure that the minimum effective amount is used.
  • They then compare the fined sample with the original wine before proceeding.
  • Many fining agents can remove desirable compounds from wine or make the wine unstable when too much is added (over-fining) and therefore it is important to add only the minimum effective amount.
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21
Q

What are the three categories of common fining agents?

A
  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.
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22
Q

How do fining agents work?

A

The fining agent must have the opposite charge from the wine colloid to be removed. The fining agent and the colloid attract each other and form a solid large enough to be removed by racking or by filtration.

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23
Q

What are colloids?

A

Microscopic particles too small to be removed by filtering

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24
Q

Why are white and rosé wines commonly fined with bentonite?

A

To remove grape-derived proteins that can agglomerate into a visible haze if warmed up (e.g. in transit). This can be seen as a fault.

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25
Q

Why is it not necessary to remove grape-derived proteins from red wine (by fining with bentonite)?

A

They bind with tannins, precipitate naturally and are removed when the wine is racked.

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26
Q

What is bentonite used for?

A

Bentonite is used as a fining agent to remove grape-derived, unstable proteins.

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27
Q

What is bentonite and how does it affect the wine?

A
  • A form of clay that adsorbs unstable proteins and unstable colloidal colouring matter.
  • It has a minimal effect on the flavour and texture of wine. It does lead to some colour loss in red wines and produces large amounts of sediment, and so wine is lost when it is racked off.
  • Bentonite can be used to fine must as well as wine.
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28
Q

List six fining agents that remove phenolics that contribute undesirable colour and bitterness.

A
  1. Egg white
  2. Gelatine
  3. Casein
  4. Isinglass
  5. Vegetable protein products
  6. Polyvinylpolypyrrolidone (PVPPl)

These fining agents may be used in conjunction with bentonite for their own properties and to avoid risk of over-fining (which in itself could make the wine unstable).

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29
Q

What is a requirement when using egg whites as a fining agent?

A

As it is an allergen, it must be declared on the label if the wine is sold in the EU and other territories if present above a specified limit.

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30
Q

What kind of fining agent are egg whites typically used as?

A

Egg whites fall under the category of fining agents that remove phenolics that contrinute undesirable colour and bitterness.

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31
Q

Why are egg whites commonly used as a fining agent for high quality red wines?

A

It tends to be used for high-quality red wines because of its ability to remove harsh tannins and clarify wine. It is gentle to the wine.

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32
Q

What is gelatine and what is it used for?

A

A protein collagen extracted from pork that aids clarification, removes bitterness and astringency in red wine and browning in white wine pressings.

Fining agent (category 2)

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33
Q

What are the disadvantages to consider before using gelatine as a fining agent?

A

It must be added in the smallest effective amount as it is easy to over-fine with gelatine, stripping flavour and character, and creating the risk of a protein haze forming later.
It is not suitable for vegetarian or vegan wine as it is derived from animals.

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34
Q

What is casein?

A

Fining agent (category 2).

A milk-derived protein that removes browning from white wines and clarifies wines to some extent.

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35
Q

What is isinglass?

A

Fining agent category 2

A protein collagen derived from fish bladders that very effectively clarifies white wines, giving them a bright appearance.

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36
Q

What are the disadvantages of using isinglass as a fining agent?

A

The smallest effective amount must be added to avoid potential for the formation of a protein haze later and the creation of a fishy smell. It is not suitable for vegetarian or vegan wines as it is derived from fish bladders.

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37
Q

What is PVPP and what is it used for?

A

Polyvinylpolypyrrolidone is an insoluble plastic in powder form that removes browning and astringency from oxidised white wine. It is a gentler fining agent than charcoal. It is rarely used on red wines, but can reduce astringency and brighten the colour.

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38
Q

What are vegetable derived proteins, used as fining agents, made from?

A

Legumes or potatoes

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39
Q

What is charcoal used for in winemaking?

A

Charcoal is used as a fining agent that removes brown colours and off-odours.

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40
Q

What is the main risk of using charcoal as a fining agent? What can be done to mitigate this?

A

Care has to be taken as charcoal over-fines easily removing desirable aromas and flavours. One option is to treat only one batch of the affected wine and then blend it with the rest of the wine to reduce this effect.

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41
Q

What is filtration?

A

Filtration is a physical separation technique used to eliminate solids from a suspension by passing it through a filter medium consisting of porous layers that trap solid particles, thus making the liquid clear. Filtration is the most common way of clarifying wine.

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42
Q

What are the two main types of filtration?

A

Depth filtration
Surface filtration

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43
Q

What is depth filtration?

A

This method of filtration traps particles in the depth of the material that forms the filter

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44
Q

What are the advantages of depth filtration?

A
  • It can cope with fluid with many particles in it; for example, wine that has just been pressed or lees.
  • Does not block easily
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45
Q

Is depth filtration an absolute filter?

A

No.
If too much pressure is applied or if the filter is used for too long, some particles will make their way through the filter.

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46
Q

What is diatomaceous earth used for in winemaking?

A

Diatomaceous earth is used as a filter medium for depth filtration

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47
Q

What is the most common filter medium used in depth filtration?

A

Diamaceous earth

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48
Q

What is another term for diamaceous earth?

A

Kieselguhr

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49
Q

How is diamaceous earth used in depth filtration?

A

The DE is wetted and used as a filter medium. Wine is sucked by vacuum from the outside of a rotary drum, through the DE, to the inside of the drum.
Once the DE is processed, it is pure silica and inert.

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50
Q

What machinery can be used in depth filtration with diamaceous earth?

A

Rotary vauum filter (exposed to oxygen)
Enclosed DE filter (can be flushed with inert gases to avoid oxidation)

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51
Q

What is this?

A

Rotary vacuum filter with diamaceous earth stained with wine.

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52
Q

What type of filtration are rotary vacuum filters used for?

A

Depth filtration using diamaceous earth

Rotary vacuum filters use this method to filter very thick and cloudy wine (e.g. wine mixed with lees). It is an oxidative process as the drum is exposed to air.

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53
Q

Why might a winemaker choose to use an enclosed DE filter instead of a rotary vacuum filter?

Depth filtration with diamaceous earth

A

Enclosed DE filters can filter very thick and cloudy wine but can be flushed with an inert gas (e.g. nitrogen) to avoid oxidation taking place.

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54
Q

What are the costs associated with depth filtration using diamaceous earth?

A
  • Inital investment of machinery
  • Per litre cost of DE is small
  • Skilled labour
  • Used DE must be disposed of responsibly, which adds an additional cost.
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55
Q

Name two other terms for sheet filters.

A

Plate and frame filters
Pad filters

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56
Q

How do sheet filters work?

A

The wine is passed through a sheet of the filtering material. The more sheets there are in the filter, the quicker the wine can be filtered because any portion of wine only passes through one sheet. Very fine graded sheets can be used to remove any remaining yeasts at bottling.

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57
Q

What type of filtration method is sheet filtration?

A

Depth filtration

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58
Q

What two methods fall under the depth filtration category?

A

Diamaceous earth (using rotary vacuum filter or enclosed DE filter)
Sheet filters

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59
Q

What are the costs associated with sheet filters?

A

Sheet filter systems require investment initially (the frame must be very robust to withstand the pressures involved), although the cost of filter sheets is low. Trained personnel must operate them to work properly.

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60
Q

What are the two types of surface filters?

A

Membrane filters
Cross flow filters

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61
Q

What is the difference between depth filtration and surface filtration?

A

Depth filtration traps particles in the depth of the material that forms the filter (DE or sheet).
Surface filtration stops particles that are bigger than the pore size of the filter from going through. Known as an absolute filter.

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62
Q

What is this?

A

Sheet filter (depth filtration).

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63
Q

Why is depth filtration not considered an absolute filter?

A

They do not have a precisely defined pore size or structure whereas surface filtration does.

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64
Q

What is another term for membrane filters?

A

Cartridge filters

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65
Q

How do membrane filters work?

A

Membrane filters catch particles that will not go through the pore size of the filter.

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66
Q

What are the disadvantages of membrane filters?

A

They are slower than using a depth filter as the pores are smaller, often less than 1 micron. For the same reason, wine must be pre-filtered first (e.g. by depth filtration) as, otherwise, membrane filters can easily get blocked.

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67
Q

When are membrane filters usually used?

A

They are usually used as a final precaution immediately before the wine is bottled to ensure that the wine is completely clear with yeasts and bacteria removed and so it’s microbiologically stable (sterile filtration).

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68
Q

What does the term sterile filtration refer to?

A

Using membrane filtration systems as a final precaution to ensure the wine is completely clear of yeast and bacteria (therefore microbiologically stable) before bottling.

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69
Q

What are cross flow filters otherwise known as?

A

Tangential filters

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70
Q

How do cross flow filters work?

A
  • The unfiltered wine passes through the filter, while also cleaning the surface of the filter, avoiding blockages.
  • The filtered wine exits the filter, while the unfiltered wine passes through the filter again
  • The result is completely filtered wine, with seperated solids.
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71
Q

What does the term stabilisation refer to?

A

The term ‘stabilisation’ is used to refer to several winemaking interventions which, if not carried out, could lead to undesired effects in the finished wine. This includes tackling the potential for unwanted hazes, deposits in the bottle and rapid changes in the wine (browning).

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72
Q

What is protein stabilisation?

A

The removal of grape-derived proteins that can create a haze in white and rosé wines after bottling (when the wine gets warm, eg transport).
Removed with bentonite as a fining agent

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73
Q

What are tartrates?

A

Tartrates, principally potassium bitartrate and, less frequently, calcium tartrate, are harmless deposits of crystals that can form in the finished wine.

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74
Q

What are the six techniques used for tartrate stability?

A
  • Cold stabilisation
  • Contact process
  • Electrodialysis
  • Ion exhange
  • Carboxymethylcellulose (CMC)
  • Metatartaric Acid
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75
Q

What fining agent is commonly used for protein stability?

A

Bentonite

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76
Q

Outline the process of cold stabilisation.

A
  • Colloids must be removed by fining before the following process, as they can prevent the crystals from forming.
  • More reliably, wines are kept at -4°C for around 8 days, forming the crystals (they are more soluable in cold temperatures). Then filtered out.

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

77
Q

What is contact process? Outline the steps involved.

A

This is a quicker, continuous, more reliable and cheaper form of cold stabilisation. 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.

78
Q

What is electrodialysis and what is it used for?

A

This process uses a charged membrane to remove selected ions. It is allowed in the EU and other territories for tartrate stabilisation. It removes both potassium and calcium ions and, to a smaller extent, tartrate ions.

79
Q

How does the ion exhange method help in tartrate stabilisation? Disadvantages?

A

This process does not remove tartrates, but, instead, it replaces potassium and calcium ions with hydrogen or sodium ions, which will not drop out of solution.

This process is not allowed in some territories as it replaces the potassium with sodium, which is not conducive to health. However, the resulting levels in wine are well below the legal limit.

80
Q

What is carboxymethylcellulose (CMC)?

A

A method used in tartrate stability.

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

It is generally used for inexpensive white wines, and keeps wine stable for a few years (not suitable for wines intended for bottle ageing).

81
Q

Why is the CMC method for tartrate stability not suitable for red wines?

A

Carboxymethylcellulose (CMC) is not suitable for red wines as it reacts with tannins, rendering it ineffective and causes haze.

82
Q

How does adding metatartic acid help in tartrate stabilisation?

A

Adding this compound prevents the growth of potassium bitartrate and calcium tartrate crystals, reducing the need for cold stabilisation.

83
Q

What are the disadvantages of using metatartaric acid for tartrate stabilisation?

A

The compound is unstable, and its positive effect is lost over time, especially when wine is stored at high temperatures (25– 30°C, meaning it is best used for wines designed for early consumption.

84
Q

What methods of tartrate stabilisation are not suitable for wines intended for bottle ageing? Why?

A
  • Carboxymethylcellulose (CMC): Prevents tartrates growing to a visible size (does not remove them). Keeps wine stable only for a new years.
  • Metataric acid: The compound is unstable and its postive effect is lost over time.
85
Q

Why is ion exchange not permitted as a method of tartrate stability in some areas?

A

It replaces the potassium with sodium, which is not conducive to health. However, the resulting levels in wine are well below the legal limit.

86
Q

What are the costs associated with cold stabilisation?

A

Cold stabilisation requires the equipment and the cost of energy to refrigerate the wine.

As it also requires fining to remove colloids, it will also add to the total cost.

87
Q

Is electrodialysis cheaper or more expensive that cold stabilisation?

A

After the high intial investment, electrodialysis is cheaper than cold stabilisation as it is faster and uses less energy.

88
Q

Is contact process cheaper or more expensive than cold stabilisation?

A

Contact process for tartrate stabilisation is a cheaper, faster and more reliable option in comparison to cold stabilisation.

It requires less energy (wine is chilled to 0°C rather than -4°C, and the tartrates form much quickly with the addition of potassium bitartrate.

89
Q

What is microbiological stability?

A

The removal of undesirable microorganisms to ensure the stability of the wine post-bottling.

For example, wines with residual sugar are at rick of refermenting in bottle if yeast bacteria are still present.

90
Q

What are three options to remove yeast bacteria for microbiological stability?

A
  • Sterile filtration (widely used).
  • The addition of sorbic acid and SO2 (less prevalent due to the smell of the effects of sorbic acid at very low levels)
91
Q

What microbes are tolerant to low PH and high alcohol levels, and are a risk to the wine’s microbiological stability?

A
  • Lactic acid bacteria
  • Acetic acid bacteria
  • Brettanomyces
92
Q

How does lactic acid bacteria pose a rick to the wine’s microbiological stability?

A

Wines with lactic acid bacteria where malolactic conversion has not been carried out or completed are liable to malolactic conversion starting up again in the bottle. (This would result in cloudiness in the bottle.)

93
Q

How can a winemaker prevent malolactic conversion from starting up in the bottle?

A

The solutions here are to ensure that malolactic conversion has been completed or to filter the wine to remove the bacteria.

94
Q

When will a winemaker typically conduct a full chemical analysis? What will it measure?

A

Before the final finishing options are carried out. About 4-8 weeks before bottling.

They will measure at least alcohol, residual sugar and free SO2.

In light of the analyis, final adjustments will be made.

95
Q

What are the typical levels of free SO2 in white, red and sweet wines?

A
  • White: 25–45 mg/L (lower than for red wines due to lower pH)
  • Red wine – 30–55 mg/L
  • Sweet wine – 30–60 mg/L
96
Q
A
97
Q

What is sparging?

A

The removal of dissolved oxygen in wine by flushing the wine with an inert gas.

98
Q

Why is dissolved oxygen generally removed?

A

Oxygen dissolved in wine can accelerate the speed of ageing of the wine and thus reduce its shelf life.

Sparging (flushing the wine with inert gas) can remove dissolved oxygen.

99
Q

Why would a winemaker choose to add carbon dioxide to their wine before bottling?

A

Especially for inexpensive youthful white and rosé wines, some winemakers will prefer a tiny bit of spritz from CO2 in the bottled wine for added freshness. If desired, CO2 is added just before bottling.

100
Q

What are the possible reasons for cloudiness and hazes in bottled wine?

A
  • The growth of yeast or bacteria in wine coupled with failure to filter adequately.
  • Poor filtering of wine (e.g. pumping wine at too high a pressure through a depth filter so that some unwanted molecules pass through the filter).
  • Protein haze where fining is not effective, where the wrong type of fining agent has been used or the wine has been over-fined
101
Q

What is the remedy of cloudiness due to the presence of yeast/bacteria in bottled wine?

A

Better hygiene in the winery, pre-bottling chemical analysis and, as necessary, filtering wine to remove yeast or bacteria before bottling.

102
Q

How can a winemaker prevent cloudiness due to unstable proteins in bottled wine?

A

Fine correctly and conduct analysis after fining.

103
Q

If a wine is cloudy accompanied by bubbles or spritz, what can be a sign of? How can it be avoided?

A

Refermentation in bottle.
Stabilise and clarify/filter the wine adequately.

104
Q

What causes volatile acidity?

A

The activity of acetic acid bacteria, inadequate levels of SO2 and excess exposure to oxygen.

105
Q

How can volatile acidity be avoided?

A

The threat can be reduced by sorting fruit to exclude damaged grapes, scrupulous hygiene in the winery, keeping vessels topped up, careful racking (to avoid excessive exposure to oxygen) and maintaining adequate SO2 levels.

106
Q

What causes reductive flavours in wine?

A

The smells are caused by high levels of volatile, reductive sulfur compounds.
These sulfur compounds can be produced by yeast under stress (due to low nitrogen levels) in the winemaking phase. Reduction also can be due to the near complete exclusion of oxygen during ageing in closed vessels, especially when lees ageing. Sometimes these odours evolve when wine is closed with the impermeable type of screw cap.

107
Q

When is reduction considered a fault?

A

At higher concentrations the reductive sulphur compounds causing reduction will produce undesirable aromas (e.g. rotten egg) that will always be regarded as a fault.

108
Q

How can reduction be avoided?

A

Reduction can be avoided by making sure yeast is not stressed. This is done by ensuring it has sufficient nutrients and oxygen, and that the must is at an adequate temperature. SO2 may need to be lowered, especially if the closure used allows very little oxygen ingress.

109
Q

What causes light strike?

A

Light strike is caused by UV radiation and certain wavelengths of visible light reacting with some compounds in the wine to form volatile sulfur compounds, giving odours such as dirty drains.

110
Q

How can light strike be avoided?

A
  • Keeping wines out of direct sunlight and flurescent lighting
  • Packaging wines in dark glass provides more protection than clear glass.
111
Q

What are the key ways to avoid brettanomyces?

A
  • Excellent hygiene
  • Maintaining effective SO2 levels
  • Keeping pH levels low and keeping the period between the end of alcoholic fermentation and malolactic conversion as short as possible so that SO2 can be added as soon as possible.
112
Q

Why is brettanomyces difficult to eradicate from the winery was present?

A

Wood can host the organism and can be very difficult to clean.
It can be present in old or new barrels.

113
Q

How can a wine that has been affected by brettanomyces be treated?

A

If wine has been affected by Brettanomyces it can be treated either by filtration or with DMDC (dimethyl dicarbonate, commercial name: Velcorin) before bottling, which inactivates Brettanomyces.

114
Q

What is dimethyl dicarbonate used for in the winery?

A

Dimethyl dicarbonate (aka Velcorin, it’s commercial name) can be used to treat a brettanomyces affected wine as it inactives the yeast.

115
Q

What considerations must be made when selecting the packaging and closure for wine?

A
  • The wine’s place in the market (early consumption vs longevity).
  • The markets where the wine will be sold.
116
Q

How is a wine affected by:
1. Too much oxygen at bottling
2. Too little oxygen at bottling

A
  1. Too much oxygen will lead to premature browning and oxidised characters (loss of fruit, development of off-flavours including bruised apple).
  2. Too little oxygen may lead to reductive characteristics (e.g. onion, rotten eggs).
117
Q

What does the term ‘oxygen transmission rate’ refer to?

A

Oxygen transmission rate (OTR) is a measure of the volume of oxygen that diffuses through a barrier over a given period of time. For bottled wine, the barrier for oxygen permeation is the closure. For bag-in-box, canned wine or wine in pouches, the barrier is the entire vessel or the weakest pathway for oxygen diffusion.

118
Q

What does the term ‘total package oxygen’ refer to?

A

This is the combination of:

  • The amount of dissolved oxygen in the wine
  • The oxygen in the head space (below the cork or other closure) – usually the greatest contributor
  • The amount of oxygen in the cork or other closure
  • The OTR of the cork or closure.
119
Q

Name two markets where glass bottles are not the preferred option for packaging.

A
  • Producer markets (e.g. France) where inexpensive plastic (PVC) containers are used to collect wine from a local winery for short term storage and early drinking
  • The dominance of bag-in-box in some markets, such as the Swedish market (nearly 60 per cent)2.
120
Q

What are the advantages of glass bottles?

A
  • It is inert and conveys no taint to the wine.
  • Bottles can be delivered to wineries in a near sterile condition, having been shrink-wrapped when still hot.
  • It is inexpensive to manufacture and comes in a range of colours.
  • In principle it is 100 per cent recyclable, but some colours are easy to recycle, others less so.
  • Glass remains the best packaging option for the ageing of wine as it is impermeable to
    oxygen.
121
Q

What are the disadvantages of glass bottles?

A
  • Glass has a high carbon footprint initially because of the heat needed to manufacture it.
  • It is heavy to transport, again contributing to its carbon footprint, especially if it is transported thousands of kilometres/miles to its final market.
  • It is fairly fragile.
  • Glass bottles are rigid; therefore, once a bottle of wine has been partly drunk, air fills the headspace and the wine is subject to rapid oxidation.
  • Wine packed in clear bottles can be spoiled by light strike from fluorescent (e.g. in supermarkets) and natural light, producing sulfur-related off-aromas.
122
Q

What kind of plastic is used for wine packaging?

A

PET (polyethylene terephthalate)

123
Q

Give some examples of scenarios where wines with PET packaging are suitable?

A

It is well suited to wines with a limited shelf life and for quick consumption and in informal settings (outdoor eating, travel) or on planes where breakage is a hazard.

124
Q

What are the advantages of PET packaging?

A
  • It is light (about 1/8 the weight of glass)
  • Tough
  • Inexpensive
  • In principle, recyclable.
  • Has a reasonable shelf-life if lined with a barrier to prevent oxygen ingress.
125
Q

What is ‘bag-in-a-box’ packaging?

A
  • This consists of a cardboard box that houses a flexible bag inside. It is usually made of a very thin aluminium foil (which acts as a barrier to oxygen) covered on both sides by a suitable plastic.
  • Alternatively, the bag can be made from a plastic that gives some protection from oxygen and is resistant to cracking, unlike aluminium foil.
126
Q

What are the advantages of bag-in-a-box wines?

A
  • Flexible pour size (one or more glasses)
  • Good protection from oxygen after wine has been poured (the bag collapses inside the box)
  • The availability of a range of sizes from 1.5–20 litres, making it suitable for home and commercial use.
  • The boxes are easy to store (they are less fragile than glass and can easily be stacked)
  • Low environmental impact (light to transport, can be recycled).
127
Q

What is the typical shelf life of bag-in-a-box wines?

A

Shelf life is in the range of 6–9 months depending on the quality of the manufacture, although the best may protect wine for up to a year.

128
Q

In what markets are bag-in-a-box wines successful?

A

Australia (where it was pioneered)
Sweden

129
Q

What is required when bottling wine in bag-in-a-box packaging?

A

The wine must have a slightly higher SO2 level than in glass to counter oxidation, a low dissolved oxygen level, no head space and low carbon dioxide (the last to avoid the bag bulging). Producers must use a high- quality tap as this is where most oxygen ingress occurs.

130
Q

What is ‘brick’ packaging?

A

Often referred to as a Tetra Pak, after the leading manufacturer, this is made of paper card with plastic layers and an aluminium foil layer that excludes oxygen and light.

131
Q

What is the main disadvantage of brick packaging?

A

The filling equipment is a big investment, and some producers outsource the filling of bricks.

132
Q

What are the advantages of cans for wine packaging?

A

They are light weight, robust, easy to open, impermeable to oxygen and recyclable.

The aluminium has to be lined with a plastic to avoid being attacked by the acidity of the wine.

133
Q

What are the main options for packaging in the wine industry?

A
  • Glass
  • Plastic (PET)
  • Bag-in-a-box
  • Brick
  • Pouch
  • Can
134
Q

What are the main properties that producers look for in closures?

A
  • Protect the wine from rapid oxidation
  • Be inert so that it does not affect the quality of the wine adversely
  • Be easy to remove and to re-insert
  • Be cheap, recyclable and free from faults.
135
Q

What are the most common closures for bottles?

A
  • Natural cork (the most popular option, with around 60% of bottles).
  • Technical corks
  • Synthetic closures
  • Screw cap
  • Glass stoppers
136
Q

What are the advantages of natural corks?

A
  • Light
  • Flexible
  • Inert (although can house harmful funghi)
  • Made from renewable, natural resource
  • Positive image
  • Come in a range of length and quality (cheaper corks for inexpensive, early consumption wines; quality corks for premium wines intended for ageing).
137
Q

What are the two challenges associated with natural cork?

A
  • Cork taint (TCA)
  • Variable rates of oxygen ingress, can lead to bottle variation amongst the same wine after bottle ageing.
138
Q

What causes cork taint?

A

TCA (2,4,6-trichloroanisole)

139
Q

How common is cork taint

A

An estimate of 3-5% of bottles closed with cork are affected by cork taint

140
Q

What efforts have been made to eliminate the incidence of cork taint?

A
  • Cleaning corks with steam extraction
  • Creating closures from recomposed cork particles that have been cleaned and reconstituted with a plastic; the result is a closure that looks and behaves like natural cork
  • Much more rigorous quality control during cork production
  • Introducing an inexpensive** polymer barrier** between the cork and the wine.
141
Q

What are technical corks?

A

These are made from cork that has been subjected to a manufacturing process and are designed to address the issues of cost and avoiding cork taint.

142
Q

Give three examples of technical corks.

A
  • Agglomerated cork
  • One-plus-one cork
  • Diam cork
143
Q

Describe Diam corks.

A

Diam corks are made from recomposed cork particles that have been cleaned and reconstituted with a plastic; the result is a closure that looks and behaves like natural cork

144
Q

Describe agglomerated corks.

A

Cork granules are glued together.

These are the cheapest option are are only suitable for inexpensive wines intended to be drunk quickly after purchase.

145
Q

Describe one-plus-one corks.

A

A development from the agglomerated cork.

The largest, central, section is inexpensive agglomerate (cork granules glued together), but it is finished with a disc of natural cork at both ends

146
Q

What is the largest producer of cork products? How are they trying to eliminate cork taint?

A

Amorim

  • They are cleaning corks with steam extraction (naturity and xpür, the latter for granulated corks).
  • Quality control screening technology (NDTech) that individually analyses and validates each stopper.
147
Q

Name two techniques used in cork production to check for the presence of TCA.

A

Gas chromatography such as NDTech (Amorim screening technology)

148
Q

What are synthetic corks?

A

Popularly known as plastic corks, synthetic closures are made of food- grade plastic with a silicone coating.

149
Q

What are the two types of synthetic corks?

A
  • Moulded Closures
  • Extruded closures
150
Q

What is the difference between moulded and extruded synthetic closures?

A

Moulded Closure
* Cheaper
* Relative rigidity, difficult to reinsert into the bottle
* Limited protection from oxygen ingress - more suitable for wines intended for early consumption

Extruded closure
* More flexible, being made by an external firm layer of plastic covering a plastic foam.
* Range of oxygen ingress rates

151
Q

What is the leading producer in synthetic corks?

A

Nomacorc (Vinventions).

Sustainable practices, materials and innovations, TCA free, controlled oxgen ingress over a range of closures.

152
Q

What is the most important issue regarding plastic, synthetic corks?

A

Flavour scalping, the loss of some flavour intensity because plastic absorbs some flavour molecules.

This has been demonstrated in labratory conditions, but unclear if it is noticeable to the consumer.

153
Q

What is a screwcap?

A

The screwcap is an aluminium closure rolled onto the outside of a bottleneck that has been specially designed for this purpose. The seal with the wine is a wad of either tin (impermeable to oxygen) or Saran (a form of plastic with low permeability to oxygen, better known for its use as cling film).

154
Q

What are the main issues with screw caps?

A
  • Require different equipment (if switching from an in-bottle closure).
  • The low-no oxygen ingress means that wines can become reductive after bottling, leading to onion-like aromas upon opening.
155
Q

How can a producer prevent reduction in screw cap wines after bottling?

A

Winemakers need to adapt the final wine to have slightly lower SO2 levels.

156
Q

Outline the consumer’s general point of view on screw caps.

A
  • Wine can be opened without a corkscrew and there is no risk of TCA
  • High degree of acceptance in UK, Australia, New Zealand etc
  • Some countries percieve wines bottled under screw cap to be inexpensive (such as the USA and China) although this is changing.
157
Q
A
158
Q

What is the major producer of glass closures?

A

Vinolok

159
Q

Glass closures
* What are they?
* Advantages and disadvantages.

A

Made from glass, but the actual seal is formed by a plastic ring

Advantages
* Wine can be stored for similar lengths of time as under closures such as natural cork
* Attractive looking

Disadvantages
* Special bottle must be used to ensure a perfect fit
* Expensive as a top quality cork; only suitable for premium-super premium wines

160
Q

What does a pre-filling (bottling) analysis check for:

A
  • If the wine is stable
  • Meets any technical specification set by the winemaker or the client
  • conforms to the required legal standards such as limits on SO2 and trace metals (e.g. copper and iron).
  • Test for any issues such as protein instability etc (if anything is found, the wine will need to be retreated).
161
Q

What is a wine’s technical specification?

A

A list of the wine’s main measurable chemical parameters.
If the wine is being made for a retailer, it will form part of the purchasing contract. This ensures that the wine remains the same—or within the limits specified—from year to year.

162
Q

16

What does a wine’s technical specification report?

A
  1. Free and total SO2
  2. Volatile acidity
  3. Alcohol content
  4. Residual sugars
  5. Total acidity
  6. PH
  7. Malic and lactic acids
  8. Total dry extract
  9. Tartrates and proteins (stability analysis)
  10. Turbidity
  11. Various minor acids (sorbic, ascorbic, metatartaric, citric)
  12. Trace metals (copper, iron, potassium, calcium, sodium)
  13. Dissolved oxygen
  14. Co2
  15. Microbial populations
  16. Taints
163
Q

What is a wine’s turbidity?

A

The amount of particles in suspension and therefore how clear a wine is

164
Q

How does a winemaker complete a wine’s technical specifiation?

A
  • In the winery with the producer has invested in the necessary lab equipment (such as High Performance Liquid Chromatography (HPLC) and Fourier Transform Infrared Spectroscopy (FTIR) which can achieve results within minutes).
  • Samples can be sent to an external labratory for a fee
165
Q

What is High Performance Liquid Chromatography (HPLC) used for?

A

High Performance Liquid Topography (HPLC) analyses the wine for its technical specification.

166
Q

What is Fourier Transform Infrared Spectroscopy (FTIR)?

A

Fourier Transform Infrared Spectroscopy (FTIR) is used to analyse wine for its technical specification.

167
Q

What are the two options for winemakers to eliminate potentially harmful yeast and/or bacteria from a wine at bottling?

A

Sterile Filtration/cold bottling
Heat treatments

168
Q

Give an example of how a winemaker might apply heat treatments before bottling to eliminate microbial threats?

A

Flash pasteurisation in which the wine is heated to a high temperature (80°–90°C for a few seconds and then cooled rapidly. The wine is then bottled.

169
Q

How are bottles typically prepared prior to bottling?

A

On a modern bottling line, before being filled with wine, the bottles are rinsed with sterile water and steam-cleaned (i.e. subject to being heated to 82°C for 20 minutes).

170
Q

What is the main difference between traditional bottling and modern bottling practices?

A

Traditional bottling practices typically involved minimal treatment (provided the wine is fermented to dryness so to inhibit microbial growth. Producers siphon the wine directly in the bottle before sealing.

Modern practices is commonly referred to as ‘aseptic’ bottling, as it involves practices to ensure any potentially harmful yeast/bacteria is eliminated.

171
Q

What are the advantages of sterile filtration/cold bottling?

A

No heat is applied to the wine and therefore there is no deterioration of quality or premature ageing of the wine.

172
Q

What are the disadvantages of sterile filtration/cold bottling?

A

The considerable amount of investment required (in comparison to flash pasteurisation) and the need to employ the highly-trained staff to supervise the technology used.

173
Q

What is flash pasteurisation?

A

A heat treament used to eliminate microbial threats to the wine before bottling.

The wine is heated to a high temperature (80°–90°C)for a few seconds and then cooled rapidly. The wine is then bottled.

174
Q

Outline the typical filling process of bag-in-a-box and pouch packaged wines.

A
  • Care is taken to avoid oxidation due to slight permeability of packaging
  • The wine is sterile filtered and sterile packed (to avoid refermentation).
  • The bags are put under vacuum before filling.
  • The wine must have a slightly higher SO2 level than in glass to counter oxidation, a low dissolved oxygen level, no head space and low carbon dioxide (the last to avoid the bag bulging).
175
Q

Outline the typical process of filling for wines in brick packaging.

A

For ‘bricks’, the packaging material is sterilised with UV radiation and the filling takes place in a sterile enclosure.

176
Q

How are wines packaged in cans usually filled?

A

Packaging in cans is a specialist operation typically done by an external partner.

177
Q

What are the three procedures for hygiene in the winery?

A
  1. Cleaning; removal of surface dirt
  2. Sanitisation; the reduction of unwanted organisms with water and a detergent or other sanitising agent and/or steam;
  3. Sterilisation; the elimination of unwated organisms with high strength alcohol or with steam. (particularly with high risk areas such as equipment.
178
Q

What is the difference between quality control and quality assurance?

A

‘Quality control’ in a winery is the set of practices by which the company ensures a consistently good quality product.
‘Quality assurance’ is the complete way a business organises itself to deliver a good product consistently and to protect itself from legal challenge (includes quality control).

179
Q

What is HACCP?

Quality Assurance

A

**Hazard Analysis of Critical Control Points
**
It is a process in which the company identifies all the possible hazards that could affect final wine quality; in effect, everything that could go wrong. For each hazard, the HACCP document will state how serious it is, how it can be prevented and how it can be corrected.

180
Q

What is ISO and what is it’s purpose?

A

ISO (International Organization for Standardization).

ISO is a external certification body that verifies companies quality standards through auditing.

The purpose of this is to give assurance to all the parties down the supply chain: the wholesaler and the retailers who will sell the wine and, finally, the end consumer.

181
Q

How does a company achieve ISO certification?

A
  • ISO sets the standards (9000 and 9001).
  • External auditors from the certification body will review the company’s own quality management system, management structure, physical and human resources and how it measures, analyses and improves its performance. This is a rigorous process for which a professional fee must be paid.
182
Q

Why might a wine company require a formal traceability system?

A
  • Respond to and investigate complaints about its wine. Complaints can come from any point of the supply chain, including the final consumer
  • Improve its practice so that similar problems do not occur in the future.
183
Q

What is the purpose of a wine’s lot number?

A
  • The lot number enables a company to trace back where the grapes came from, what additives have been used and what processes the wine went through. The winery must keep a detailed record on each step of the production process.
  • Larger firms and those concerned about traceability will keep samples of every batch so that they can investigate what has gone wrong and compare returned bottles with their library of samples. Common problems include cork taint, tartrate crystals and faulty or missing labels.
184
Q

What are the two types of containers used for bulk shipping of wine? What is the difference?

A

Flexitank; a single-use, recyclable polyethylene bag that fits into a standard container. Coated with a barrier to prevent taint from an external source and to reduce oxygen ingress.
ISO tank; A stainless steel vessel built to the ISO standard. Reusable.

Insulated with temperature control (known as reefers) available at an extra cost.

185
Q

What is the main advantage of shipping wine in glass bottles?

A

The advantage of shipping wine in bottle is that the entire product – the wine, the bottling, the labelling and any external packaging – is controlled by the producer.

186
Q

What are the disadvantages of shipping wines in glass bottles?

A
  • The smaller amount of wine that can be shipped in one container and therefore a higher cost
  • The financial and environmental cost of shipping the weight of glass as well as the wine
  • Potential damage to the wine due to high and fluctuating temperatures in transit, and potential spoilage of labels and packaging in transport
  • The shorter shelf life of inexpensive wine because it is bottled earlier than if it were bottled in or close to the final market.
187
Q

What are the advantages of shipping wine in bulk?

A
  • More environmentally friendly
  • The greater thermal inertia of a whole container filled with wine; meaning less fluctation of temperature
  • Strict quality control: the key parameters of a wine can be measured at the point of filling the container and again on emptying it
  • The wine can be adjusted at the point of bottling close to the final consumer
  • The shelf life of a wine can be extended as this is calculated from the time of bottling
188
Q

Why is shipping wine in bulk more environmentally friendly compared to shipping wine in glass bottles?

A

One container can hold the equivalent of 32,000 bottles in liquid rather than 12,000- 13,000 filled bottles, reducing the carbon footprint of the wine; it is cheaper, for the same reason

189
Q

What are the main disadvantages of shipping wine in bulk?

A

Loss of the direct relationship with the producer and the transfer of business and employment opportunities from producer countries to the countries close to the final market.
Shipping in bulk is only commercially viable for larger companies.

Wine Production (22 decks)

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