broadly defined as a fortified wine subjected to controlled oxidation to create
a distinctive flavor. More specifically,
the special oxidized character of sherries are often describe as baked, nutty,
and caramelized. Since the flavors of
sherry are derived from complex organic compounds including acetaldehyde,
phenyl ethanol, esters, and wood extractives, the aroma and flavor of the original
relatively neutral flavored grape variety vanishes during production.
The Andalucía region of southwest Spain has been making
Sherry wines for nearly two millennia from the non-descript white Palomino
grape. While the Spanish produce a
variety of sherry products, there are essentially two basic types of
sherry. Fino sherries derive their light-straw color and hazelnut, light
oaky aromas and flavors from flor yeast fermentation. Conversely, Olorosos sherries are darker, more amber in color, generally
sweeter and are produced in an oxygen rich environment without flor yeast.
sherry wines usually fall between the color and aroma extremes between fino and
olorosos ranging from light yellow to medium brown in color. Sugar content of most American sherries range
from 1.0-2.5% for dry, to 2.5-4.0% for standard and up to 10% for cream
Palomino is not a widely grown in American vineyard (213 acres in California in
2014), domestic sherry wines are produced from an assortment of mostly white
grape varieties. In the west, in
addition to Palomino, Mission, Grenache, Orange Muscat, and French Colombard
are used while in the east, Chambourcin, Niagara, Delaware, Muscadine, and
Orange Muscat are favored varieties for sherry production.
American Sherry-style is Made
normally picked at 22-24 degrees Brix, then crushed and pressed, or pressed
immediately on arrival at the winery minimizing skin contact. Free-run or light pressed juice is often used
to make Fino-style sherries while the juice from further pressing usually
creates the Olorosos-style sherries. The
pressed juice called “shermat” is then fermented to dryness (no measurable
residual sugar to make the white base wine. The new base wine racked off the
lees, and fortified with grape brandy or wine spirits.
fermentation, sherry winemakers must make a crucial stylist decision - whether
or not to oxidize the base wine with or without yeast. This decision determines the final sherry
style; Fino or Olorosos.
oxidation involves the inoculation of base wine with a special yeast strain
called flor. “Flower” in Spanish, flor yeasts produce what looks like thousands of tiny white flowers
piled on the surface of the wine. The base
wine is fortified to about 15%, which allows the development of a flor yeast film.
“surface-film” method of making flor
sherry can be time consuming and expensive so some winemakers have adopted a
variation called the “submerged culture” technique. This process most often applied by larger
producers involves inoculating 15% alcohol base wine with flor yeast in a stainless-steel tank where air or pure oxygen is
continuously bubbled through the wine. The tank is regularly stirred or agitated to keep the yeast cells
suspended and the development of acetaldehyde closely monitored.Acetaldehyde is an organic chemical compound
that is the key to the sensory definition of sherry. Once the base wine has reached the desired
acetaldehyde and flor yeast character,
the wine is again fortified to 17-19% then racked off the lees.The finished fino-style sherry is then left to age.
vintners elect the non-yeast approach and produce Oloroso-style sherries by either long aging in partially filled oak
barrels or by “baking” the base wine. Competitively
priced American sherries are often produced by the heating the wine in the
presence of air at 120 to 140 degrees for 30 to as many as 120 days.
improve with age and different styles dictate differing aging schemes from a
few months to a few years. Most vintners
age sherries in American oak barrels to gain a stronger aroma and drier
taste. Traditionally, the solera system is used for storage and
blending sherry. This the same technique
often used in the fractional blending of port-style wines consisting of stacks
of barrels with each row containing a different sherry vintage. The oldest wine in the bottom tier is drawn
for bottling and is replaced with wine from the tier above and so on for usually
five or more tiers. Few true solera systems are found in American
sherry wineries. While fractional
blending may still be done, the expense and effort of maintaining the solera is challenging.
American sherry may involve some blending to adjust sweetness, color and
complexity in order to achieve the vintner’s unique stylist objective. Once the final blend has been achieved, the
sherry may undergo a polish filtering, cold-stabilized and finally, bottled.