Initially the sparger was placed
through side valves on the wooden
tanks. However this proved too close
to the lees. Now it is dropped down
from the top of the tank so that the
level, just above the tank bottom (in
the lees, if lees are present), can be
more easily adjusted.
Like the real estate mantra of location,
location, location, that for production
winemaking should be control,
control, control. With so many
complex processes occurring during
fermentation and ageing, the more a
winemaker can do to keep any wine
from going awry, the healthier his/her
peace of mind.
The improvements in microOx systems
in the past few years have
focused on providing a winemaker
with better control - upgraded rate
flow control, better monitoring of the
whole system, adjustments for container
size, quick repairs for equipment
problems, and being able to service
more tanks or containers at any
one time.
WESTEC OXBOX
The Westec OxBox was developed
by Dr. Jeff McCord, vice president of
research at StaVin Inc. Westec/ Belli
Corporation (Healdsburg, CA) manufactures,
sells, and services the OxBox
for the wine industry.
The OxBox is simple in design, utilizing
a combination of electronic flow
meter and mechanical flow controllers.
An Excel spreadsheet calculator
is used to determine flow rates
needed to produce the desired
microOx rate in a given volume of
wine. This type of system operates
independent of head pressure for
tanks up to 66 feet in height. The system
uses a 10-micron stainless steel
diffuser, which minimizes fouling,
positioned two to three feet above the
tank floor.
McCord recommends microOx and
StaVin Oak as tools to turn tanks into
"barrels," adding oxygen only after
MLF. While the winemaker never has
complete control of vineyards and
fermentation,
|
there should be no need to
microOx a wine prior to MLF. Ideally,
the winemaker has harvested at
proper maturity, utilized proper yeast
nutrition, used macro-aeration, controlled
temperatures, and pressed the
wine off the fermented grapes at the
proper time.
If this is the case, color stabilization
has been initiated; and sulfide and
vegetal characters have been minimized.
Winemakers may then think of
the tank as a barrel. They can then
adjust the oxygen input to the wine to
meet their desires for aroma, flavor,
and texture.
For more information, contact:
StaVin, Inc., tel: 415/331-7849,
www.stavin.com OR Westec, tel:
707/433-9342.
OENODEV
Rich Jones is a consulting winemaker
and representative for the
Oenodev micro-oxygenation systems
and Galina Seabrook is the regional
U.S. manager of Oenodev and
microOx/ elevage consultant.
Oenodev is an outgrowth of the
research that French winegrower
Patrick Ducournau did in the early
1990s for high tannin wines grown in
the Madiran region of southwestern
France. Their continuing understanding
of the process divides winemaking
into three stages for using microOx:
Stage I - after primary fermentation
and before malolactic fermentation -
wine developing structure "structuration,"
Stage II - after malolactic fermentation
when wine is harmonizing and
SO2 has been added,
Stage III -structure developed during
ageing, and before bottling.
In Stage I - MicroOx is used to stabilize
color, diminish the perception of
vegetative tastes and aromas, increase
structure, richness and youth, develop
wine into more beefier and aggressive
presence. Because of the high reactivity
of a wine at this stage, amounts of
20 to 120 ml/l/mo O2 are common. A
higher amount of
|
dissolved O2 is also
acceptable during this period. Thus, it
is very important to start the treatment
immediately after alcoholic fermentation,
when there is an abundance of
monomeric material in the wine.)
Stage II - This is a time when the
SO2 level will be adjusted. During this
period, low O2 addition rates of 1 to 10
ml/L/month are recommended. It is a
time when the color of the wine is
fixed; aldehydes are minimized, and
the tannin molecules are polymerized,
which softens them. The wine often
develops a chocolate and cocoa richness.
During this stage, the temperature
needs to be monitored. Lower temperatures,
typical in the winter, increase
oxygen solubility. Additionally, higher
levels of SO2 can limit the structuring
effects of oxygen.
Stage III is the harmonization
period. This would be the equivalent
of wine ageing in barrels. Little oxygen
is needed at this point; too much and
the tannins become dry.
Oenodev components are computer-
controlled systems capable of
feeding one or many tanks. A ceramic
diverter/sparger is used at Sebastiani
where Lyon feels it provides very fine
bubbles. The various computer units
can deliver 0.5 to 200 ml/L/month for
up to 60 tanks per control unit.
Oenodev units are capable of switching
to nitrogen as a back up, if the oxygen
supply is accidentally used up.
For more information, contact:
Oenodev USA, Inc., tel: 707/332-1078,
www.oenodev.com.
AMERICAN TARTARIC PRODUCTS
Larry Biagi is the senior winemaker
with American Tartaric Products
(ATP). His winemaking experience
spans 40 years, including stints at
Sonoma Vineyards, Pedroncelli,
Geyser Peak, and Trentadue. Biagi and
ATP represent the Parsec line of computerized
gas controllers from Italy.
|
