
The
distillation companies strive to maintain high and strict standards in the process,
trying to get premium products, but in the "jima" is where the production
process begins, as well as when the agaves are selected and harvested.
When
the raw material arrives, quality control begins by taking a sample heart of
every lot; that sample is analyzed, and the sugar levels and the cooking times
are set.
COOKING:
The
hearts are cut in two or four parts, according to their size, in order to achieve
perfect cooking and optimum use.
The agaves are placed manually inside the ovens. Once this is done, the cooking
process starts, and it lasts an average of 48 hours, injecting water vapor into
the oven.
The
purpose of cooking the "piña" is to hydrolyze the sugars and
make them soluble, since the insulin is not very soluble in water and it can't
be fermented in a direct way.
In the traditional cooking process, masonry ovens are used; however some modern
tequila producers use autoclaves.
After
cooking, the hearts of agave will let the sugars flow and therefore the musts
will be ready for fermentation.
MILLING:
After
perfect cooking, the agave hearts are moved to the milling area.
The
milling is divided into several stages. The purpose is to extract the sugars
that are in the agave's fiber. This is performed in mills, whose structure goes
from stone to crushers and stainless steel mills, according to the maker.
The
stages of the milling begin with the ripping of the "piñas",
which consists of processing the cooked agave by a machine that crumbles it.
Later on it's taken to a section where cane-type presses will squeeze the juices.
Once
squeezed, this fibrous material goes by a section where water is added for the
maximum extraction of sugars. As a result of this process, an agave juice is
obtained, and it contains 12% of sugars. With this raw material the must is
formulated for the fermentation.
FERMENTATION:
Once
the must is prepared for fermentation, it is inoculated with a microbial,
which
can be a pure yeast wax "saccaromyces cerevisiae" or some other species.
When
the must is ready, the fermentation begins. That is one of the most important
stages but not too studied because the alcohol is produced as well as other
organoleptic components that compose the tequila. This fermentation is carried
out in open stainless steel tanks of variable volume. The temperature is always
under control and oscillates between 30 and 42 degrees Celsius.
This fermentative process can last between 12 and 72 hours, depending on the
desired amount of alcohol
which
can be 6% for mixed tequila and 4.5% for "Tequila 100%". Once the
fermentation is over, the must rests so the important aromatic components can
be generated.
DISTILLATION:
There
are two
different ways to perform the distillation: using alembics or columns; the first
way is more common. In the first case (alembics) a tandem of copper alembics
is used, which helps to eliminate the unwanted sulfuric elements.
EIn
the first alembic, the dead must is heated with steam, and it distills until
reaching an ordinary intermediate product, with an alcohol concentration between
25% and 30%; the solid particles, some water, and the heads and tails have been
removed from it. The first batch contains the volatile components that distill
before ethanol under 80º C, like methanol, isopropanol, and ethyl acetate.
The second batch has less volatile alcohols such as amyl and some esters.
In
the second alembic, the ordinary product is distilled again to enrich its alcoholic
content up to 55%, besides refining the product considerably. This 55% alcohol
tequila is considered an end product, and that's the one that's sold in bulk.
Before being bottled, this distillate is diluted with deionized water, to achieve
finished products between 38 to 43%.
When
using columns they are used up to three in tandem. In this case the must enters
the column from the upside, to contra flow with vapor, while the volatile compounds
that condense in the different plates evaporate; usually when columns are used
instead of alembics, the product is more neutral due to the selective distillation.
MATURATION:
Once distilled, the end product is concentrated in tubs where it is diluted
to pass it to the "pipones" or casks, where it will be matured depending
on the kind of tequila desired. In the maturation
process, the last stage is carried out in the white oak or encina casks
or
"pipones", wood that confers to the end product a very peculiar taste,
color, and aroma. Those qualities depend on factors like the age, the thickness
of the stave, the alcohol content, and the resting and aging conditions. The
humidity and ventilation are important because in the aging process there are
oxidative reactions.
At
last, before bottling the product, it's necessary to remove some solids which
come from the staves through filtration with cellulose or activated charcoal.