Port anD the Douro 133produced deep-coloured aromatic Port, it was concluded that as a result of the lack of
aeration during fermentation the wines lacked the structure and complexity of those
made in lagares or autovinifiers. The Vinimatic has since been used successfully for the
production of unfortified Douro wine. A number of other producers, notably Barros,
Ferreira and Taylor, built new wineries with temperature-controlled stainless-steel vats
equipped for pumping over, a process known in Portuguese as remontagem. All three have
subsequently developed new devices (see below). It is fair to say that, with the possible
exception of autovinification, none of these methods has provided sufficient extraction to
produce premium-quality Port.
Nowadays, large wineries are fully automated from start to finish. As soon as a
consignment of grapes arrives at the winery, a core sample is taken from each of the
dornas or bins and the must weight or Baumé is recorded by refractometer to determine
the amount of fermentable sugar. This may be used to determine a bonus over the basic
grape price to the grower, who will be paid when the harvest is over. Some shippers
will also pay a further premium for selected grape varieties. After the dorna has been
weighed it is tipped into a reception hopper from where a large Archimedes screw (known
locally as a sem-fim meaning ‘without end’) conveys the grapes to a crusher/de-stemmer,
which removes the stalks from both red and white grapes. Before the crushed grapes reach
the fermentation tank or autovinifier, the must is dosed with sulphur dioxide at levels
of between 40 and 150 milligrams per kilo depending on the condition of the grapes.
Larger amounts are sometimes used to delay the onset of fermentation and thereby aid
extraction. Most winemakers will adjust the acidity of the must at this stage to around pH
3.6 to 3.7 by adding the appropriate amount of tartaric acid. A few producers inoculate
with selected dried yeasts but most rely on sulphur dioxide to delay fermentation, thereby
culling undesirable strains of wild yeast. Specific cultured yeasts only tend to be used when
a fermentation is reluctant to start, as there is a very real risk of ethyl acetate forming if the
fermentation fails to commence fairly promptly after crushing.
Having been among the first to experiment with autovinification in the early 1960s,
the Symington family have made significant improvements to the system. When they
were first developed, most autovinification vats were cubic in shape and built from epoxy-
lined reinforced concrete with a capacity similar to that of a traditional lagar. As concrete
is a poor conductor of heat, in warm years Port ferments continued to suffer from
overheating. Conversely, in cool vintages, without any means of circulating the must prior
to the onset of fermentation, maceration was reduced. As a result a number of important
modifications were made to the autovinification system during the 1980s and 1990s.
The most significant of these was the introduction of temperature control. Apart from
its obvious benefit during a warm vintage, temperature control enables the winemaker to
run off each ferment as late as possible, thereby prolonging skin contact. Now that electric
power is readily available, autovinifiers are equipped with pumps that can be switched
on to extract colour before fermentation begins. At Warre’s Quinta da Cavadinha and
the Symington’s Quinta do Sol winery, a battery of stainless-steel autovinification tanks
has been installed, some of which are squat in shape to bring the surface to volume ratio