The Wine Foils War
Bottle Capsules and their Environment Impact
This is quite a technical newsletter, which has to cover a fair bit of science to explain the wider ramifications of different types of bottle closures on the environment. As such I have added a wine based cocktail recipe at the end so if you are getting bogged down in detail you can skip to the end for a moment and perhaps fix yourself a cocktail to steel yourself before coming back to the details.
Capsules are the plastic, foil, or composite sleeves that cap the top of wine bottles that are sealed with a cork (by cork I mean natural corks, composite, and plastic corks). Nearly all wine bottles have them. For now, I will ignore screw caps, in which the bottle is designed so the cap apparatus does the role of the capsule.
Due to costs and, aesthetics, most capsules are made of plastic, with some more expensive wines using plastic coated metal foil. As they tend to have a plastic component, capsules can be used as part of the design of the bottle for it is not to hard to print a design onto the plastic, or use a specific coloured plastic.
Historically they were made of lead foil and were an alternative to capping the bottle in wax. The reason for some sort of additional layer over the cork was mainly to stop anything getting at the cork and to add a further protection against air seeping through the cork and so oxidizing the wine.
For instance, if you had lots of wine in a cellar you would want something to stop any possible rodents etc having a nibble of the corks. And if wine was to be aged for a decade or so, the tiny seepage of air through even the best cork might start to have an impact.
There is also a suggestion that these seals meant that the wine could not be adulterated, as with just a cork it could be removed, the wine swapped for something cheaper, and then the cork replaced. I do not think this is a major reason for their use, however, as even capsules can be faked and if you are worried that wine is being adulterated there are bigger issues that just the bottle closures at play.
In terms of the purpose of bottle closures, the simplest function is to keep the wine in the bottle.
As all closures fullfill the basic job of keeping the wine in the bottle, it is worth thinking about other reasons for them. Most closures, along with the bottle, are made to lower the chances of the wine spoiling over time. The major reason for wine to spoil with time is oxidation, caused by air getting to the wine. There are other wine faults that can be cause by bad storage, but most will not be linked to the closure.
The only other major fault linked to closures is corking. Corked wine is a term which describes wine that has notable levels of a few complex organic compounds (mainly 2,4,6-trichloranisole, aka TCA and 2,4,6-tribromoanisole, aka TCB) which smells a bit like mouldy carboard or wet dog. This is typically cause by fungi, most often from infected corks, although the wine can be infected before bottling if the barrel etc is infected.
Oddly enough these would not happen naturally as the fungi has to digest complex chlorine or bromine containing molecules which are rare in nature but commonly used as cleaning agents or pesticides. Â They can also be created when things like bleach react with organic compounds in wood, so can become present in a cork either as the cork tree grows or in later treatment.
Anyway, this is meant to be an article about capsules and the like, rather than the issues of cleaning agents altering the chemistry of wine. So back to closures. Corking will not be caused by the exterior closure and is rather rare. Indeed, that is why wine is stored on its side as damp corks are less likely to shrink and let in air, but are slightly more likely to develop fungal infections. Because of this it is possible to argue that air tight capsules, which could permit the wine to be stored upright would help to stop corking being an issue.
As well as corks there are other forms of bottle closure that are suitable for wine. The most common alternative is a crown caps (like what you get on most beers). These do not tend to need any further sealing, but sometimes are dipped in wax to ensure the seal is fully air tight. They provide a good seal but are not normally as good, in terms of air seepage, as a properly fitted cork with some sort of extra level of external seal. With that said, I have drunk considerably aged beer, sealed only with a crown cap, that had aged very well without any notable degradation from oxidation.
Screwcaps work in a similar way to capsules but the top part is designed to come off without much work and is built to be firm and to screw into a threaded patterned moulded into the top of the glass neck. Many also try to mimic the look of capsules as wine sealed with corks, and capsules tend to be associated with quality. As they have no other method of closure the idea that the use of foil and plastic is wasteful makes less sense. Both crown caps and screwcaps tend to only use a single part and so are less wasteful in terms of resources.
Screwcaps are also an interesting closure as they are one of the few that are easily resealable (though of course once opened do not provide such a tight seal and will not stop oxidation from the air now in the bottle). Another resealable closure is the type of glass stoper, with a small plastic seal, called a vinolok after the main brand, or more generically a glass-on-glass closure, or simply a glass stopper. These are useful as they can be reused on almost any standard glass bottle, but other than with some German wines (for the company to invent them was German) are not common, most likely due to cost.
Note that these closures and non-natural corks avoid most of the issue of corking, but can have flaws in regards to other methods of spoilage, such as oxidation.
The vast majority of wine bottled is drunk within a year of purchase. This means that for most bottles, the closures should be chosen with mind to the likeliness of wine faults developing. As oxidation through a well fitted cork without a further seal is very slow, if the wine is drunk in a year or two it is highly unlikely that the absolute tiny amount of oxidation will have caused an issue. Also, as most wine drunk within a few years is not stored in dank cellars for long periods the need for a seal to prevent rodents and other critters getting at the cork is virtually non-existent.
Note that as most use metal and plastic they are very hard to recycle, plus as most are not fully removed, the small top piece often cut off before serving is almost never recycled, with the remaining part discarded when the bottle is recycled. If this is only done for a few wines made to be aged for significant periods of time, which makes up only a few percent of the world’s wine, it would be excusable as it would then be worth using a small amount of resources to avoid considerable spoilage. But as most wine is drunk within a year, there are millions of capsules being binned each year.
This might not seem like much of an issue as each capsule itself is tiny and so you might think that it is negligible in terms of global waste. First of all, even if it were negligible in global terms it would still be worth thinking about minimising that little bit of waste. However, because so many bottles of wine are wine are consumed each year the cumulative effect of binning lots of little bits of plastic is significant.
Of course, it would be too simple to say that just because capsules are not needed for the preservation of wine, they are unnecessary and should be scrapped for their obvious use of resources.
As I mentioned capsules are very good at protecting bottles against tampering, especially if they include a brand specific design and are a notable colour. For instance, it would not be hard to buy plain black capsules and use those on standard sized bottles that had been adulterated, but to mimic a capsule in a proprietary colour with a specific logo, would take far more effort than adulterating the wine would normally be worth. Â
It could also be justified that by adding an extra layer of protection they stop the cork being contaminated if stored badly, but if this is needed, perhaps by legislation, it would be better to focus on not storing wine where it is likely to come into contact with contaminants in the first place.
However, other than legislative reasons based on those justifications, I do not think this plays a major part in why capsules are used. Wine is not a simple foodstuff, it has so much cultural baggage that needs to be addressed. If you have grown seeing all good wine having capsules it might make you associated wine with capsules as being good.
Linking into this is the importance of wine bottle design. I think anyone would be lying if they said they bought wine without thought of the packaging, at least when buying in person. As most wine is bought by the bottle, the way it is designed is a key part of any brands marketing. Wine labels are limited by law, in that they have to contain certain information. This means that producers are not fully at liberty to play around with their designs, for they cannot avoid including certain things. This means that every small part of the bottle will often be used to reinforce the brand’s signature look and feel.
As such the capsule is often used as a striking way to add a bit of colour to the top of the bottle, without having to worry about how it will make text legible or not. With sparkling wine especially, the capsule will cover a fair amount of the neck of the bottle and so give plenty of space for design.
All in all, I am not convinced by any argument for the need for capsules for the vast majority of wines. I do understand that if you are bottling something made to be aged for a further 20 years, and so often quite an expensive product, it makes sense to use a closure system that minimises the change of spoilage. But for most wines, this is not the case, and it is frankly lazy to suggest that it is needed aesthetically. If the capsule is the only thing that draws the eye to a bottle, a new design is needed.
However, the issue of legislation, which often calls for capsules, and the fact that unilaterally changing the way bottles have been presented will not change expectations around how wine looks, means that it is very unlikely that single producers can make much change.
What is needed is lobbying and an examination of any legislation that mandates capsules, to balance any risks of contamination or spoilage with the environmental aspects. Plus, the larger wine producers need to communicate and decide as a block to move away from capsules. This will help to provide wide spread change to the expectations of what wine looks like, and so let smaller producers do similar things without having to worry about consumers avoiding their wine for that reason.
This is not the only issue that wine needs to address to avoid contributing further to the environmental crisis, but it would be a good start. Also, by rethinking what a wine bottle should look like, other issues with bottles such as unnecessary punts and excessively thick bottles could be changed.
Such change is vital if wine is to continue as a functioning industry for with climate warming vines will not be able to grow as they did and some styles of wine might even become impossible to make. It is also important for wine producers, and consumers, to think about the world as a whole and think about what a glass of luxury means for the future.
As promised here is a Cocktail for you:
The New London Sour:
50ml London Dry Gin
25ml Lemon Juice
15ml Sugar Syrup
25ml Rosé (ideally something fruity and quite dark in colour) Â
Shake the gin, juice and syrup with ice, and strain into a tumbler filled with ice. Then float the wine on the top of the drink, by carefully pouring it over the back of a spoon, so there is a notable colour difference between the pale bottom portion and the bold colour of the wine.
For far more informed and better written discussions of the environmental impacts of wine have a look at, the wine maker, Jas Swan’s writing and tweets. It was this twitter thread that inspired this newsletter.
For a perspective of similar environmental concerns about beer and how they can be address have a look at this brilliant article for Pellicle by Emma Inch.
For a lovely Valentines focused idea of wine paring, with an infectious sense of fun have a look at this article for Burum Collective by Rachel Hendry.
As always I hope you enjoyed reading this and so please do share it and sign up for free to get emails each time I post something, if you have not done so already.