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We observed that grape vines that are stressed in some way
can produce juice that has a higher
level of undesirable chemicals.
So that can make the wine taste bad.
I'm a Flavor and Aroma Chemist with Oregon State University,
Food Science and Technology Department.
I'm also a core faculty member with the Oregon Wine Research
Institute.
Basically, at OSU.
My job is to study aroma and the flavor compounds in your food,
including wine.
One of the projects is to investigate
the off flavor associated with stress of the vine.
People describe these off aromas with words
like tequila, gasoline, shellfish, peanut, or ashtray.
We do not know which stresses to the vines
are responsible for these off flavors and aromas.
In my research, I'm identifying the chemicals
that are responsible for these off flavors.
This instrument is a gas chromatograph mass
spectrometer.
It is our primary tool for the work we do here.
We take a sample of our bad-tasting wine
and extract the flavor compounds into a small vial.
Then, we inject it into the GC instrument.
The instrument analyzes the chemical components.
Everything happens inside of the instrument,
but it will identify about 1,000 chemical components
in the wine.
It takes about one hour.
As each chemical is scanned by the GCMS,
a little puff of the odor of that chemical
comes through this cup and I can smell whatever it is.
These are the chemicals that make up aroma and the flavor
in the wine.
Ethyl butyrate-- apple, fruity.
Ethyl hexanoate-- pear and fruity.
If the wine has high concentrations
of hydrogen sulfide, it we have a sulfur smell
like rotting eggs.
Now, we are looking at good-flavored wines.
We can identify some of the viticulture practices that
have produced those compounds.
We found that when the leaves around that cluster
were removed, there were higher concentration of compounds
that have produced desired aroma such as beta damascenone.
We found those compounds in the grapes
and then also in the wine.
From many experiments of this kind,
we know something about how the physiology of a vine
affects the chemistry of grapes.
We can trace how the different practices
affect the compounds that produce a high quality of wine.
We are looking for a pattern in the chemistry.
And then, once we find the pattern,
we can look into the viticulture side.
And then, hopefully, find out what
we can do in the vineyard to make those wines better.
I'm grateful for the Oregon wine industry
for supporting my work and my colleagues' work.
All wine growers and wine makers understand the importance
of up-to-date research that helps
them to stay competitive and keep Oregon wines on top
of the market.
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