The above apparatus is used to run an Aeration/Oxidation test for free sulfur dioxide (SO2), a winemaker's primary tool in fighting oxidation and to a lesser extent microbial spoilage. It looks pretty 'mad-scientist'-like but it's relatively practical chemistry at work.
The pear-shaped flask at the bottom contains the wine and a big dose of acid, which combined with aspiration (pulling some air though the solution with a vacuum pump) liberates the free SO2. The free SO2 essentially travels up through a condenser (cold water) and is trapped in the solution in the top flask. The top flask contains hydrogen peroxide (H2O2) and an indicator solution/dye. It begins the test a green color and turns purple in the presence of the SO2. We can then titrate this solution with Sodium Hydroxide (NaOH) to calculate the free SO2. Ill spare you the boring details of the chemistry, its pretty easy and fairly accurate; it's downside is that it takes 10 minutes of aspiration to run a test.
We began another round of racking in the cellar this week. Ryan racked our 2006 wines from the Camel Hill Vineyard(Merlot, Cab Sauv, Cab Franc and our Lexington Meritage (so far 68% Cab Sauv/20% Cab Franc/12% Merlot)) to tank yesterday. While he was washing the empty barrels i ran analysis (Free SO2, VA (Volatile Acidity), pH and TA) on the wine in tank. We are going to do a little blending, correct the SO2 and return the wines to barrel.
I feel like I have a pretty good gauge on where these wines are going at this point in their life. 2006 is a much more classically styled vintage, especially when compared to 2005. The 05's needed ever day of the almost 2 year we gave them in barrel, while the 06's should be ready for bottling in another 4-5 months. The are much more suave and nuanced; the 05's are much more structured.
The Lexington and Cab Franc have darker and denser flavors- think blackberry and coffee. We only have a single barrel of Camel Hill Cab Sauv and it is getting blended into the remaining Camel Hill Merlot. It added a little more heft to the Merlot and filled in the mid-palate nicely.
I am headed up to Tahoe early tomorrow for a little snowboarding action; got a new board last week and am super excited to try it out.
More soon....
Wednesday, January 9, 2008
SO2 and Camels
Labels:
2005,
2006,
blending,
Cabernet Franc,
Cabernet Sauvignon,
Camel Hill,
Meritage,
Merlot,
racking,
SO2
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2 comments:
I like your Aeration/Oxidation Test Setup where did you get it?
Ken,
Thanks, its my favorite out there as well. The gentlemen at R&D Glass in Berkeley, CA have it. I buy as much of my lab glass from them as i can- great people.
R&D Glass
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