Practical Winery
65 Mitchell Blvd, San Rafael, CA 94903
phone: 415-453-9700 ext 102
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November/December 2007
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.
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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.
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, OR Westec, tel: 707/433-9342.
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,
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.
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