If you’re a wine producer, what do you want your customers to be drinking? Presumably, you want them to taste the wine you made. And if so, you should want every bottle to be consistent with the next.
Think about it from the wine drinker’s perspective. You’ve just discovered a fantastic bottle, so you buy another one to take to a friend’s house for dinner the following week. But when you open it, the bright, fresh fruit you had the first time feels a bit more like jam or baked fruit. Not that it’s necessarily bad, but it’s not the wine you got so excited about.
So what gives?
There could be a variety of factors at work in producing wine bottle variation. Part of it could be circumstantial, like the food you’re having (or not) with the wine, or even your mood, fatigue level, etc. Some people would say that the weather or the biodynamic calendar could influence how the wine shows. More likely, however, more practical factors are at work, including the way the wine was handled at bottling, the closure used, and storage conditions.
How to Keep it the Same
Avoiding cork taint is certainly one clear way to increase consistency, but there are also other questions at hand. In statistics from the International Wine Challenge, a major wine competition held every year in London, cork taint generally represents over a quarter of the questionable faulty bottles, but oxidation and reduction represented well over half of the problems reported. So getting oxygen ingress and sulphur levels under control at the bottling stage can be very important to making sure wines consistently present themselves as intended, from one bottle to the next.
Addressing specific mechanical issues at the moment of bottling can have a significant impact, too. As Malcolm Thompson, vice-president of strategy and innovation at Nomacorc, indicated at a Wine Science Forum held in Napa, California, bottling line audits conducted by Nomacorc have shown great variations in oxygen ingress from one wine—and one bottle—to the next.
The bottling contribution found through these audits—headspace oxygen and dissolved oxygen resulting from bottling—varied from 0.5 ppm to 13 ppm. This may not seem like much, but considering that a Classic+ Nomacorc closure lets in 2.6 ppm of oxygen per year, this means that the impact of bottling can be equivalent to one to three years of aging or even more.
Different on the Shelves
Other tests conducted on wines picked off store shelves showed that these differences can indeed be significant. One test conducted by Wines and Vines magazine in 2012 showed significant variations in oxygen levels found in bottles bought directly from retail, showing that all these bottles were likely to show variations in aromas and taste. Nomacorc conducted similar tests in 2014, in France, buying 25 different wines in retail (10 bottles per wine), before doing a series of tests on the wines. Forty percent of the 10-bottle sets showed significant differences in free SO2 levels (4 mg/L or more, with 3 sets showing differences of over 10 mg/L), revealing variations in oxygen exposure from either the closure or handling at the time of bottling. Sensory tastings showed perceptible variations within six lots, meaning that almost a quarter of the wines were basically inconsistent from one bottle to the next.
As Malcolm Thompson pointed out at the Wine Science Forum, taking care of these variations at bottling is “low-hanging fruit”—meaning relatively easy to accomplish. Steps like using neutral gases in the tanks, bottling line, and bottles, for instance, as well as using a closure that provides a predictable and reliable amount of oxygen ingress, can help reduce bottle-to-bottle variations.
Working for greater consistency is a way to ensure that the months of work spent growing grapes, and the further months of work spent turning these grapes into wine, are reflected as they should be in the final product—every time you open it.