Dissolved CO2 in Austrian Wines...

[TomHill]

Next week, at SantaFe W&C Fiesta, Val Masten will be giving a Seminar on Austrian wines. Below are some questions I’ve sent to her on the subject of Dissolved CO2 in Austrian Wines:

@Tom

Val,
I will be attending your Seminar on Austrian wines Fri morning. I have a few questions on
Dissolved CO2 in Austrian wines. You can address them in the Seminar or, preferably, to me
directly afterwards.

I first started observing dissolved CO2 in NZ SauvBlancs a fair number of yrs ago, but paid it little attention.
As I drink a lot of Austrian wines, over the last 3-4 yrs, I’ve been observing the presence of dissolved CO2
in Austrian wines with greater & greater frequency. Generally the tip-off of dissolved CO2 is a distinct “pop”
when the seal on the screwcap is broken.

Mostly, I observe the presence of CO2 by sight in the glass:

1. Sometimes there is a cloud of tiny/tiny bubbles that swirls around in the glass in almost a cloud, that persist for
   quite a long time (many/many minutes). This swirling cloud can be absolutly mesmerizing and interesting to watch.
2. Sometimes there is a cloud of less tiny bubbles that immediately cling to the side of the glass and only dissipate
   with persistent swirling of the wine.
3. Sometimes there is a cloud of tiny bubbles that immediately agglomerate to a chain of small bubbles that encircle the
   glass on the surface. Sometimes they dissipate very rapidly, othertimes not, even w/ persistent swirling.
4. Never do I observe a stream upwards of tiny/tiny bubbles like you get in a fully carbonated sparkling wine, indicating
   that the amount of dissolved CO2 is much less than a Champagne.

Then I observe the impact of the dissolved CO2 on the palate:

1. Sometimes there will be a distinct spritz on the palate, not unlike Lambrusco, that persists.
2. Sometimes there will be a tiny prickle on the palate on the front of the mouth that immediately disappears.
3. Sometimes this prickle will immediately disappear and leave behind an utterly vapid wine. It seems as if this
   prickle gives an ersatz acidity that disappears immediately, leaving nothing behind.
4. Sometimes this prickle will disappear immediately and leave behind a solid wine w/ a bracing acidity. This seems
   to be the majority of the cases. You get a brief prickle, it’s gone, and the wine is good…very little impact on the wine.

From what your read, leaving/imparting this dissolved CO2 in a wine is designed to impart a sense of acidity to the wine.
I don’t find this imparted acidity quite the same as the true acidity you get in a wine. It seems to be an ersatz acidity.
This dissolved CO2 can come (primarily) two sources:

1. The dissolved CO2 is left in the wine as a leftover product from the CO2 production during fermentation and the
   winemaker intentionally makes efforts to preserve this dissolved CO2 in the wine up to bottling.
2. The wine is actually sparged with CO2 at bottling to “freshen” the wine.

Of course we “know” (as we’ve been told by the experts) that #1 is a more “natural” process for achieving CO2 in the
wine and #2 is “not natural”, is interventionist winemaking. That, somehow, the dissolved CO2 leftover from fermentation
is somehow “better” than adding CO2 at the bottling time.

So, I have a few questions on this subject of dissolved CO2 in wines, specifically as it applies to Austrian wines:

1. Do your observations of dissolved CO2 in Austrian wines coincide with my observations above? Both the
   visual aspects and the tactile aspects?
2. Has there been a conscious effort by Austrian winemakers to preserve/add dissolved CO2 in their wine
   over the last few yrs?
3. When the winemakers prepare to bottle their wine, is the amount of dissolved CO2 something they
   actually measure or do they just let whatever happens/happen?
4. Is leaving dissolved CO2 in a wine a good thing or a bad thing? Or is it just simply a stylistic choice by
   the winemaker?
5. Is adding CO2 at bottling time an “unnatural” act, to be deprecated, and preserving the “natural” CO2
   from fermentation somehow more “natural” and, therefore, “better”?? I am, of course, baiting a bit the believers
   in “natural” wine, which I think many of your Skurnik wines are.

Don’t waste your time, Val, responding directly to these questions. But I would like to hear your thoughts on the subject
whilst you’re at the SFW&CF next week.

Would, of course, be interested in the thoughts of all the esteemed folks here on this board as well on the subject.
Should I have included the ??

Tom

[John_Morris]

Have you ever discussed this with German winemakers? It’s pretty common there, too.

I asked Dr. Carl von Schubert at Max. Grunhaus about it on a visit many years ago and he attributed it to the fact that they ferment in some kind of pressurized vessel (which I never understood). I asked Dr. Katharina Prum about the tendency of Prum wines to have more spritz than many Germans, and she said she wasn’t sure but thought it might be because they don’t move the wine around a lot, which tends to bring the CO2 out of solution.

Just a hunch, but I bet the temperature of the cellar might make a difference, with wines made in cooler cellars retaining more CO2.