alcohol content

[phoebe]

Our local wine shop recommended a 2002 Shiraz from South Eastern Australia (Marquis Philips) to go with a very rich mushroom, beef and barley soup we make. It was a terrific pairing. However, we were REALLY feeling the alcohol after only the first glass. Then we read the label and saw that it was 15.5%. That's got to be the highest alcohol content we've ever seen on a wine. Is it? Is it unusual? We've been told that California wines tend to be higher than French (and we actually prefer a lower one). What is this, an Australian version of macho?

[kokopuffs]

I'm from California and have drunk local wines having alcohol content at 14% - excluding ports - like a '75 Petit Syrah from Ridge Vinyards running at around the upper 14 or 15% in alcohol.

[Peachcreek]

Alcohol content is determined by the amount of fermentable sugars in the grapes. The more sugar, the higher the alcohol content. Geography, weather/climate and grape variety play an important role in how much sugar is contained in the fruit. Yeast fermentation will yield @ 16.5%/vol. of alcohol before the alcohol will poison the yeast and stop fermentation. Anything with an alcohol content higher than @16.5/ vol. is attained by adding distilled spirits like brandy or neutral grain spirits.
With high sugar content grapes, a vintner has a few choices: blend in other less-sweet fruit, leave some sugar in the wine, or ferment it out and end up with high alcohol. Grapes also contain unfermentable sugars that give wine its' fruit flavor.
Heres' a question- In high residual sugar wines, like reislings, are the residual sugars fermentable or nonfermentable?

[lsharrott]

Most red wines fall into the range of 12-14 %. This is usually do to wine style but it is often influenced by tax issues. Any wine over 14% is taxed as a much higher rate than the lower ones. So in order to avoid this tax wine makers stay below this threshold. Many wines are considered too “hot” with alcohol levels of 15.5%. It requires a full wine to counter that much alcohol.

Residual sugar in wines like Riesling could be fermented but the style of the wine is sweet and fruity. Too much alcohol and the fruitiness of Riesling would be diminished. This is what gives this particular fruit it character. Riesling is fermented with a yeast strain that is less alcohol resistant than strains that would produce 16.5% alcohol. The yeast begins to die and stops fermenting well before all sugar is consumed.

[kokopuffs]

Is it possible that a yeast inhibitor is added to reislings at some point?

[Peachcreek]

You can stop fermentation with sodium bisulfite or something similar to it. Sold in winemaking shops as "Campden tablets", it is also used to sterilize winemaking equipment, bottles, etc.
Look on the label and a lot of wines will say "contains sulfites".
I'm also curious about what other sterilizers are used nowadays since the larger problem of sulfite allergies is being addressed. I think Cakebread Cellars has sulfite-free wines.

[kokopuffs]

Just an fyi but I think that the chemical to which you refer is called sodium metabisulfite. Yet I'm thinking of another chemical used as a yeast inhibitor whose name I can't remember from my home winemaking daze.

[lamington]

My wine cellar (dusty cupboard ) here in Melbourne contains reds with alc/vol of 13-14.5%. The relatively high alcohol content in many Australian reds proved a problem, as far as a I know, during early attempts to establish the export market.

--lamington

[lsharrott]

Sodium metabisulfite in an acidic environment like wine converts to sulfur dioxide (SO2). This in high doses will stop fermentation. Potassium Sorbate may be the other chemical you are thinking of. This is not effective in stopping fermentation but does prohibit fermentation from restarting in wines that have been sweetened.

I believe that all wines in the US have to have to be label "contains sulfites". Even without the addition of SO2 the fermentation process actually creates some sulfites.

[mike]

If you mix it with boubon the ABV content goes through the roof. LOL you americans just dont know how to drink.

[mike]

ps sodium metabisulphate is evil stuff and is also used for potao whitening. I believe the cia used it in Afghanistan to subdue the rebels.