Packaging and Closures Flashcards
Oxygen management when packaging:
The amount of oxygen in the final container will determine the shelf life and expected development of the wine
- Too much oxygen = premature browning and oxidised characters (loss of fruit, development of off-flavours including bruised apple).
- Too little oxygen = reductive characteristics (e.g. onion, rotten eggs).
Winemakers measure the total package oxygen. 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.
Packaging options:
Glass:
Advantages:
* 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.
Disadvantages:
*High carbon footprint (because of the heat needed to manufacture it)
* It is heavy to transport (high carbon footprint)
* 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. Green bottles give better protection and brown still better.
Packaging options:
Plastic
PET (polyethylene terephthalate) is a form of plastic
- light (about 1/8 the weight of glass)
- tough
- inexpensive
- recyclable
- It must be lined with a barrier to reduce the ingress of oxygen and therefore give a reasonable shelf life.
- 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.
- Special filling equipment is required as the PET bottles are inflated at filling.
Packaging options:
Bag in Box
This consists of a cardboard box that houses a flexible bag inside
- 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.
Advantages
- flexible pour size (one or more glasses)
- good protection from oxygen after wine has been poured (the bag collapses inside the box) - availability of a range of sizes from 1.5–20 litres, making it suitable for home and commercial use
- easy to store (they are less fragile than glass and can easily be stacked)
- low environmental impact (light to transport, can be recycled).
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.
Shelf life is in the range of 6–9 months
Very successful in certain markets: Australia, where it was pioneered, and in Sweden.
Packaging options:
Brick:
Aka Tetra Pak (after the leading manufacturer)
- made of paper card with plastic layers and an aluminium foil layer that excludes oxygen and light.
- Can be entirely filled with wine, thereby excluding oxygen
- Accepted by consumers at lower price points and does well in markets where price is a major driver (e.g. Germany).
- More attractive contemporary designs are appearing.
- The filling equipment is a big investment, and some producers outsource the filling of bricks.
Packaging Options:
Pouch
Similar to the bags inside bag-in-boxes.
Available in larger (e.g. 1.5 litre) and single serve sizes.
Packaging Options:
Can
Suitable for wine to be consumed early:
- light weight
- robust
- easy to open
- impermeable to oxygen
- recyclable.
- The aluminium has to be lined with a plastic to avoid being attacked by the acidity of the wine. - The filling equipment is a big investment, and producers will generally outsource the filling of cans
Closures options:
Natural cork:
- Light
- flexible (while requiring a specialised tool to remove it)
- inert (but can house harmful fungi)
- comes from a renewable, natural resource.
- Positive image in the eyes of consumers
- Range of length and quality
Disadvantages:
- TCA (affects 3–5% of bottles)
- Variable rates of oxygen ingress = different rates ageing in the medium to long term for 2 bottles of the same wine
Developments to reduce/eliminate TCA:
* cleaning corks with steam extraction
(by Amorim)
* 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 (championed by Diam) (This is a form of a technical cork.)
* much more rigorous quality control during cork production, including high-cost high-tech solutions (e.g. gas chromatography) to check for the presence of TCA
* introducing an inexpensive polymer barrier between the cork and the wine. This is an impermeable membrane between the cork and the wine that gives a wrinkled appearance on the end of the cork and excludes any aromas reaching the wine from the cork.
Closures options:
Technical corks
- Made from cork that has been subjected to a manufacturing process and are designed to address the issues of cost and avoiding cork taint.
- Agglomerated cork = cork granules are glued together (cheapest / suitable for inexpensive, youthful wines)
- One-plus-one cork = central section is inexpensive agglomerate + a disc of natural cork at both ends.
- Diam corks (available with different oxygen-ingress rates)
Closures options:
Synthetic closures
Plastic corks made of food- grade plastic with a silicone coating:
- Moulded closures (cheapest / rigid / limited protection from oxygen ingress / flavour scalping = plastic absorbs some flavour molecules)
- Extruded closures (more elastic, range of oxygen-ingress rates = suitable for ageing /
Closures options:
Screwcap
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)
- Permit almost no oxygen ingress = wines can become reductive after bottling (slightly lower SO2 levels at bottling needed)
- Can be opened without a special tool
- No TCA from cork
Closures options
Glass stoppers
Closure made from glass (actual seal is formed by a plastic ring)
- Wine can be stored for similar lengths of time as under closures such as natural cork
- As expensive as top-quality cork
- Often referred to by the Vinolok (brand)
Pre bottling analysis:
- free and total SO2
- volatile acidity
- alcohol content
- residual sugars
- total acidity
- pH
- malic acid and lactic acid
- total dry extract
- tartrates and proteins (stability analysis)
- turbidity (the amount of particles in suspension and therefore how clear a wine is)
- various minor acids: sorbic, ascorbic, metatartaric, citric
- trace metals such as copper, iron, potassium, calcium, sodium
- dissolved oxygen
- CO2
- microbial populations (various strains of yeast, bacteria)
- taints, e.g. TCA
