Here is an aide memoire for the range of bottle closure solutions in use today. Their aim is to overcome the risk of premature oxidation and cork taint (TCA), whilst allowing a desired rate of oxidative ageing, or not, as required by the winemaker.
Where a product is claimed (essentially) TCA taint-free, this equates, at least in the case of Diam, to be taint free below the limit of quantification of 0.3 ng/l.
As usual this is a work in progress, as new products are launched/discovered, in alphabetic, rather than order of introduction …
|name / manufacturer||brief description, example application|
|1+1 technical cork, and again||These are used for wines with a consumption period of 2-3 years. I used to call this a 2+1 technical cork, but the industry term is 1+1. It consists of essentially TCA taint free components, comprising a very dense agglomerate central cork body, closed at each end with a disc of high quality natural cork. Example. Other variants include 2+2, with 2 discs at each end, and 2+0 with 2 discs at just one end, the latter being used for sparkling wine closure.|
|Diam||An essentially cork taint risk free, agglomerate, natural cork based granule closure, available for still (in a range of permeability) and sparkling wines and spirits. Examples, still and sparkling wine.|
|Nomacorc||A closure created from sugarcane-based polymers, so recyclable. It is available at six levels of oxygen ingress, termed OI, to facilitate a particular rate of oxidative ageing. Example.|
|Procork||A gas permeable membrane is applied to both the top, and bottom, surfaces of the cork. Image. Example.|
|Screw cap, and again||The screw cap for wine was launched onto the market in 1959, and patented in 1976, Known as Stelvin, it has been increasingly popular since the 1990s, and is widely used in New Zealand and the new world, with varying degrees of resistance elsewhere, for reasons such as customer expectation of a traditional cork, and the cost of adapting conventional bottling lines.
The cap consists of an aluminium shell, lined with a synthetic seal, with a specifiable gas permeability. For wines requiring the maintenance of freshness over a short drinking window, the permeability will verge on gas tight.
Given their relatively recent adoption in the sphere of fine wine, performance in terms of extended wine ageing, is still being evaluated. Research has shown that, in many cases, there seems no significant difference between wines aged under screw cap and under natural cork. However, whilst the difference between wines of the same lot bottled under screw cap will be relatively insignificant, those under cork will differ, to some degree – which to me is one of the beauties of cork – who wants a wine to taste the same every time, which is why I prefer vintage, to NV champagne.
Their popularity has driven cork closure producers to improve their processes, to reduce the risk levels of TCA assocoayted with natural cork.
In 2017, Coravin launched a screw cap variant of their wine sampling mechanism.
|Vinolok||An elegant, recyclable, glass stopper-like closure, with a synthetic sealing ring, the specification of which either excludes, or permits gas exchange at some desired level. Example.|
|Zork||Originating in Australia, introduced in 2010, it is a synthetic closure with, the convenience of a screw cap combined with the ‘pop’ of a cork, resealable in both still and sparkling wine variants. It consists of 3 elements – a tamper proof locking mechanism, a synthetic seal, and a pop up opening and push down resealing piston. Example. Image 1, 2 and 3. I am not convinced that this remains in production today.|