Wednesday, August 05, 2009

Should Wine be Bottled like Beer?

In the most recent issue of Wines and Vines English wine writer Jamie Goode has a very readable article on Oxygen and Wine. Jamie covers several aspects including a research initiative being funded by Nomacorc, bottle closures and the technology being used to measure oxygen in wine. One of his conclusions is that the variability of oxygen pickup during bottling can be a significant problem for wine. But the most interesting point he discusses is that the beer industry has spent considerable time and effort to avoid the presence of oxygen in its product. In relating this to wine Jamie notes

George Crochiere gives some examples of the sorts of levels of oxygen that might be introduced to wine bottles during different filling procedures. In the worst-case scenario, a gravity-filled bottle sealed with a cork without any vacuum will pick up 2.6ppm oxygen during filling and have a further 1.8ppm oxygen in the headspace, giving a total of 4.4ppm.

If a vacuum filler is used and the headspace is evacuated, this figure will fall to just under 1ppm. If a screwcap is used and the bottle is filled using a vacuum filler, then pick-up in bottle filling is 0.6ppm. If liquid nitrogen dosing is used, headspace pickup is 0.7ppm; without this it is as high as 4.75ppm, giving an initial TPO (Total Pack Oxygen) of 5.36ppm. Crochiere points out that in the beer industry, the best-run bottling lines give oxygen pick-ups of between 0.05 and 0.15ppm, while average lines are 0.2-0.4ppm.

Obviously bottling under a vacuum and using a screwcap cuts the level of oxygen dramatically but not to the level of the best bottling achieved with beer. Even an average beer bottling line reaches levels that are better than the best wine practices. So why is wine not bottled like beer?

Clearly one argument is that we still don’t know what level of oxygen wine requires especially for maturation (cellaring). And we also don’t know whether different wines may need different levels of oxygen when placed in bottle. There are companies producing liners for screwcap that allow different levels of oxygen to pass. Different levels of oxygen, that does make the imagination wander. Just picture, one day Penfolds Grange may come in screwcaps of different colors. One color will signify a liner that allows little or no oxygen ingress/egress so you can cellar the wine for decades, another color may signify a liner that allow a little oxygen to enter so that maturation is hastened over a decade or less, and another may let in even more so that you can quaff your Grange as soon as you get it home from the wine store. And, of course, seeing as the Fosters Group makes both beer and wine your Grange for the cellar is likely to come with a twist top crown seal!

1 comment:

Anonymous said...

First, when beer is bottled a 'fober' injects a single drop of room temperature water onto the top of the cold product. This single drop causes the headspace to foam pushing the oxygen from the bottle and displacing the headspace with foam and CO2. This premise can only work with wine when the product has been carbonated. Second, the filler valves in a pressure filler are designed for a double pre-evacuation meaning once the head seals to the bottle for filling there is a series of tiny cams that control vacuum, pressurize, level, vacuum and pressurize. The filler bowl and spouts on a 9 spout pressure filler are often of higher value than an entire 9 spout still filling line. Third, in wine the single drop liquid nitrogen doser is patented by one company ONLY and the cost of the machine to drop one drop of liquid nitrogen is in excess of $25,000 US. This price hardly justifies the .1ppm difference or the savings of nitrogen gas vs. liquid nitrogen ... that is unless your winery sells millions of cases. It is worth mentioning that a light vacuum on fill does not reduce the level of oxygen pickup when bottling wine; it speeds the rate of fill as the gravity fill does not have to overcome the oxygen being displaced from the bottle as the product goes in. The prevention of oxygenation during the fill of still product comes from a de-aeration of the bottle where the oxygen is removed and replaced with an inert gas such as nitrogen. finally, when bottling under screw cap it may be more ideal to bottle under argon rather than nitrogen. Argon is a much heavier gas and will sit better inside the headspace when a bottle moves down the line from the filler to the screwcapper. Lastly, there are many processes that take place prior to bottling that can cause the product to pick up oxygen like pressing the must, filtering, racking, transferring, and more. get the product in the bottle and keep the oxygen out is the golen rule but there are many more precautions that can be taken in terms of product preservation long before the product goes to the bottling line that can improve its shelf life and overall quality.