The Champenois were the first to embrace this idea. Up until the end of the 1960s champagne did its second fermentation on natural cork. Then, in the late 1960s the crowncap was introduced, which at the time had a cork liner.
“Producers found it was much easier to work with crowncaps,” says Benoît Gouez, chef du cave of Moët & Chandon. “This was perfect for non-vintage or young vintage releases, but they found they weren’t ageing as well as wine bottled with natural cork.”
These days Moët uses crowncaps with different liners, depending on the wine. For wines destined to be aged on lees for a long time, it uses crowncaps with lower oxygen transmission liners.
But for their own private collection they still use natural cork, in part because the crowncap liners can’t match the low oxygen transmission rate (OTR) of good corks, and also because Gouez believes that cork brings something to the wine: “A layer of flavours.”
Now this idea of using OTR as a winemaking tool post-bottling is catching on with other closure types. Diam was the first to adopt it, offering its engineered technical corks at a range of OTR levels. The cork is made from a mix of cork flour, synthetic microspheres and food-grade binding agent, and varying the ingredients changes the OTR. Diam is available in very low, low or medium OTR forms.
Significant research
Nomacorc has invested significant sums in sponsoring research into the effect of varying levels of OTR on wine development across a wide range of wines.
The idea behind this work is both proof of concept and also to provide a data framework from which it can offer winemakers specific advice about which product from its portfolio would best suit their wines. Now it offers a range of OTR levels in its Select series of synthetic cork.
Significantly, the company has made two further steps that look likely to breathe life into the synthetic category.
The first is a dramatic improvement in the visual appearance of the closure, with end printing and a grain effect. The new generation of Nomacorc looks very impressive indeed, and is a million miles away from the horrible aesthetics of first generation plastic corks.
The second is the development of Select Bio, a range made with a proportion of plant-derived rather than petroleum-derived plastic. “We have been certified by Vincotte in the 60%-80% plant-based polymers category,” says Nomacorc’s brand communications manager for the Americas, Katie Myers.
The next generation Select Bio has just been launched and is a stunningly good-looking closure. And now screwcaps have joined the engineered OTR party with the two biggest players both announcing a new range of liners with a spread of OTR levels.
Screwcaps consist of two components: the cap itself, and the liner or wadding. The liner is important: it is this that determines the oxygen transmission properties of the closure.
Silver lining
For a long time, screwcaps came with only two liners for wine use – Saranex and Saran Tin. You can tell the two apart quite easily. The former has a white appearance, while the other is shiny silver. The first (the white one) is composed of a polyethylene (PE) wadding with an inert Saranex layer (referred to as Saranex). This is a multilayer film developed by the Dow chemical company that acts as a gas/water barrier.
