Dissolved CO2 in Wine??

Howie wrote;
Home wine makers who use kits (wines made from concentrated grape juice) seem to have a greater problem with dissolved CO2 and the directions even include a de-gassing step, which involves stirring the wine vigorously for several minutes. I don't know why wines from concentrates would be more prone to dissolved CO2.

Hi Howie,
A lot of the kits claim to be a 4, 6, or 8 week kits (ready to drink).

Salute

Andrew,

do you happen to know how the initial 'charge' of CO2 dissipates in the wines you're referring to? I am curious because in my area (I import Italian wine) there's always quite a bit residual at bottling (enough to be visible, in any case).

Oliver, I'm afraid I don't know the chemical specifics of dosage rates or dissipation and retention, my awareness of the technique doesn't extend to the chemistry. The instance I have the closest knowledge of involved making the addition in the leadup to bottling, to ensure the CO2 didn't just dissipate again.

I've wondered too if sparging bottles or tanks just prior to use involves some CO2 takeup, but have no idea of the chemistry there either.

cheers

Andrew

Andrew wrote;
I've wondered too if sparging bottles or tanks just prior to use involves some CO2 takeup, but have no idea of the chemistry there either.

Besides up-take of CO2 maybe during bottling using a certain inert gas might strip the wine of some CO2. Like Mark W and Mark L stated it all depends upon application and what you are trying to achieve.

Salute

Places that do long, cool fermentations will wind up with aqueous solutions saturated (i.e. holding the maximum amount soluble) with CO2.

As someone who ferments under cool - to - cold conditions I can attest to this. The temperature in my wine cellar is around 50 degreed F in the fall during fermentation and drops to nearly freezing in winter. At that point a thermostat turns on a couple of good old incandescent light bulbs that supply more heat than light. Now, in March, it's still only about 35 degrees. All my wines are characteristically spritzy. I've tried a couple of ways to degas but haven't come up with one that's both satisfactory and inexpensive. Suggestions?

Hi Dan,
I got buddies that make more whites than reds and they too have tried all sorts of things to degas their wines. The stirring with the handle of a fermentation spoon, the “paddle type” device or long stainless steel whisk attached to a variable speed hand drill. One even modified a carboy bung to attach the “Vacum-Vin” hand pump device to the carboy. (But then again Downstate we don't have your Upstate temperatures to deal with).

Salute

As has been said, all wines contain a fair amount of dissolved CO2. In general we see about 900mg/L in white wines and 500mg/L in red wines for them to feel "right". Wine with no dissolved CO2 tastes pretty flat. The gas does two things. It adds a bit of spritz, sometimes barely perceptible. Secondly, some of the CO2 becomes carbonic acid, which makes the wine taste slightly more acidic.

White wines that are made and stored in steel tanks with little racking will have more dissolved CO2 than red wines stored in barrels. I would suggest that all winemakers know how to increase or reduce the level of CO2 and there is nothing wrong with this. One might argue that it is slight manipulation to sparge C02 into a wine that has lost too much but I cannot see any harm or skulduggery in doing so. Alice F would probably disagree, but she's not a winemaker.

CO2 can be removed by sparging the wine with nitrogen. This is done while racking through a long hose. It's a very common method. CO2 can be added in the same way, just connect the sparger to the CO2 tank.