Sirah, and Petite Verdot. Some
custom-crush clients request it, and it
is used, as noted above, for some
wines headed to the bulk wine market.
In both cases, the wines can be whole
lots, or portions intended for blending.
The purpose is to soften the tannins
and improve color intensity.
Duration of the use of microOx is
largely determined by weekly monitoring
of the free SO2 and DO and regular
tasting. Researchers (Waterhouse
and Laurie, 2006) noted that the O2
tends to collect in layers. It is important
to collect samples from low in the
tank, or in larger tanks, to circulate the
wine to be sure of an accurate sample.
During microOx use, tank temperatures
are kept at 58° to 60°F. Typically,
oak inserts are used in conjunction
with microOx, rather than wine going
MicroOx is continued until tasting
indicates that the tannins have softened
and the color is appealing.
Stopping microOx will stop further
aldehyde production, and allow the
reactions to go to completion.
J. LOHR WINERY
The Cypress line of wines from J.
Lohr (San Jose, CA) is sourced from
Central Coast grapes. Made in a fruitforward
style, the wines are primarily
tank-aged. Winemaker Jeff Meier uses
microOx, often in conjunction with
chips or inserts on the Cabernet,
Merlot, Shiraz, and Chardonnay wines
in that line.
Chardonnay sometimes gets a
hyper or macro-oxygenation dose;
done to soften high phenolic juice
prior to fermentation. The juice gets 9
ml/L of O2 for one day, allowed to settle
overnight, then racked off juice lees
to start fermentation. During fermentation,
0.5 ml/L O2, along with untoasted
oak chips, are added for sweetness.
MicroOx is also used at J. Lohr for
high tannin, and/or over-extracted
Cabernets and Merlot in the Estate
Series. The rate is between 5 and 80
ml/L/month done primarily between
primary fermentation and MLF to
soften tannins. Chips or inserts are
often added to reduce herbal