It started with white Burgundy. Both Scott and Benoit, who drink their fair share of the wines, noticed that many of the Grand Cru and Premier Cru bottles they opened were sealed with corks made by the French company, Diam. It got them to thinking.
Scott: “Burgundy is a place that’s pretty set in its ways, for good reason. So when we saw producers using Diam corks on their top wines instead of traditional corks, we did some research.”
Cork has been the closure of choice in the wine industry for centuries. Harvested from cork trees, it’s a natural, renewable resource, and has an elasticity that allows it to compress and rebound, making for a nice tight seal. It also lasts a long time and doesn’t degrade when it comes in contact with wine.
But as worldwide demand for corks has grown, the industry has run into trouble. The traditional method of producing cork, which is to punch it out of the harvested bark (think of a paper hole punch), results in vast inconsistencies in the product.
Benoit: “Corks produced in the traditional way inevitably introduce unwanted variation in the wine. The most infamous is TCA (2,4,6-trichloroanisole), the compound that can cause musty, basement-like aromas and flavors in wine. But standard corks can also introduce hundreds of other unwanted chemicals into the wine and can differ significantly in terms of elasticity and the amount of oxygen they allow into the bottle. One might be a great seal for 30 years, but another may only last six months. Using them is like playing the lottery; every bottle is going to be slightly different, which is a problem, especially with wines meant to age.”
Diam corks are made with natural cork from trees, but the processing is completely different. Rather than punching out the cork from the bark, Diam washes and grinds the cork (utilizing only the suberin, the choice part of the bark), and then uses its patented DIAMANT® Process to extract compounds that cause sensory deviations, including TCA. To these clean, uniform cork granules Diam adds water and a binding agent, reconstructing and molding the corks one by one. Many wineries, including Realm, use a plant-based binder made of castor oil and beeswax.
The result are corks that have a high level of sensory neutrality as well as consistency from one closure to the next. What’s more, because of its processing technique, Diam offers corks guaranteed to seal bottles for a certain number of years. A Diam10 will guarantee a bottle for 10 years, a Diam20 for twenty years and so on. Winemakers also have several options to choose from in terms of oxygen transfer, i.e., how much and how quickly the cork will allow oxygen to reach the wine in the bottle.
Benoit: “For aging you want some oxygen to reach the wine, and there are two factors. The oxygen initial release (OIR) is the amount of oxygen inside the cork that gets released into the bottle during the first six months. The oxygen transfer rate (OTR) refers to how much oxygen will enter the bottle each year. Diam has options that allow me to manage both. I can regulate how much oxygen is getting into our wines over a period of time, depending on that wine’s profile and how long I want it to be able to age. It’s another level of control.”
Realm bottled its 2020 Fidelio and 2020 La Fe Rosé with Diam corks and plans to expand their use with other wines in the portfolio, including The Bard and The Tempest, beginning with the 2021 vintage.