138 Port anD the Douro
dry white wine. Lighter wines, however, are inoculated with selected yeast cultures and
fermented at 18 to 20°C to develop and retain primary fruit character. However, most
of the Douro’s indigenous white grape varieties lack intrinsic character and a number of
winemakers introduce Moscatel (Muscat) to enhance aromas and flavours. Around the
town of Favaios, where much of the Moscatel is planted, some small producers make
an aromatic varietal Moscatel by fortifying the wine prior to pressing and leaving it in
contact with the skins. This skin maceration technique is also used in southern Portugal
for the production of Moscatel de Setúbal.
FortiFiCation anD aguarDente
All Port (with the notable exception of a special category of light, dry white Port known as
‘Leve Seco’) is fortified to a strength of between 19 and 22% ABV. In a process known as
encuba, the wine is run off when approximately 5 to 6% by volume of natural alcohol has
been produced from the fermentation, and is then mixed with the colourless grape spirit
known as aguardente (often erroneously referred to as ‘brandy’). The ratio is roughly 115 litres
of aguardente to 435 litres of wine, thereby making up a 550-litre pipe (the standard unit
of measurement in the Douro). The blending process is generally carried out by pumping a
measured quantity of spirit into a holding tank simultaneously with the free-run juice and
the pressings. The new wine is then homogenised and given a certain amount of aeration
by pumping over. The action of mixing fermenting must with aguardente causes a sudden
rise in temperature, which can be undesirable in a young wine. A number of shippers have
now taken to chilling the spirit down to 12°C, which helps to arrest the fermentation and
ameliorates ‘thermic shock’.
The style of a particular Port is determined to a great extent by the point at which the
must is run off and fortified. A shipper looking to maintain a marginally sweeter house
style (e.g. Graham) will therefore choose to fortify slightly earlier than a producer whose
wines are drier (e.g. Dow). However, shippers may also produce small amounts of sweet
wine specifically for blending at a later stage. Known as geropigas, these are wines (either
red or white) with 150 grams per litre or more of natural sugar that have been fortified
almost as soon as fermentation begins. Red geropigas tend to be relatively pale in colour
due to the limited amount of skin contact. Conversely, some ferments may be permitted
to continue for rather longer than normal to produce darker, drier wine with 20 to 50
grams per litre residual sugar, which is also used for blending and fine tuning. In a few
instances, a small amount of aguardente may be added to musts before fermentation,
raising the level to 3 to 4% by volume, to curtail the metabolism of the yeasts and thereby
further aid extraction.
Considering that it makes up a fifth of all Port wine, until the late 1990s remarkably
little thought was given to the character and quality of the aguardente. Throughout the
nineteenth century and into the early years of the twentieth, most spirit was distilled
locally in the Douro from wine that was surplus to requirements. Following João Franco’s