Before more
scientific techniques were developed, the drying of fruit under the sun was an
ancient technique by which the likes of dates, figs and grapes could be preserved.
The history of this process goes back millennia but was probably introduced to
Spain by the Moors who valued raisins highly as foodstuffs and used them in their
cuisine.
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| Pasas or sun-dried grapes |
In winemaking
the technique was used to increase effective sugar content in the grapes
thereby increasing potential alcohol, or simply producing much sweeter must. It does, of course, reduce the amount of liquid. We all know that PX and Moscatel grapes are
dried out in the sun- or raisined - to lose some of their water content and
thus increase the proportion of sugars for sweet wines, but it used to happen
with all the grapes as the Palomino produces a fairly low alcohol, low acid
must. Indeed some Palomino is still dried, as in Lustau's Anada 1997.
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| A redor de esparto. Those used for pressing have a central hole. (foto:gentedejerez) |
The newly
picked grapes were collected in a canasta (a wicker harvesting basket) or a
wooden pannier or nowadays in a plastic box but all with a similar capacity of
11-12 kilos (roughly one arroba) and laid out on “esterillas” or “redores de
esparto” (esparto grass mats) of @ 80 - 100cm diameter in the sun of the “almijar.”
This is an Arabic word meaning a large flat area of ground or yard suitable for
laying out the grapes, usually in front of the vineyard building which housed
the “lagares” (treading troughs) and overnight shelter for the harvesters. The
time spent “asoleando” depended on the weather at harvest time. If the grapes were
not ripe enough to produce enough sugar for @ 15%/vol alcohol in a dry wine, a
day or two of sunning would correct that. If it was intended to produce a sweet wine, a
couple of weeks were needed to bring the sugar content up to the desired @
500g/l.
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| The old way: sunning the grapes in the almijar of Palomino & Vergara |
After one
day the grapes lose about 10% of their weight (mostly water) and so the sugar
content will be proportionately higher. Overnight the grape bunches are covered
to avoid the risk of rehydration and potential rot from the dew, and the next
day they are turned over to even out the sunning. The proportion of malic acid and,
to an extent, tannin will be reduced, while that of tartaric acid will
increase.
“Yeso”
(gypsum =calcium sulphate) used to be added – and occasionally still is – perfectly
legally, in the proportion of about 1-2 grams per kilo. This will help the wine
fall bright and give the must a little more acidity. This ancient process is
known as “plastering”, and while Victorian doctors ranted about its supposed deleterious
effects on the wine, it is in fact perfectly harmless in reasonable proportions
and is allowed under European law for wines produced in hot places where they have
lower acidity. Most bodegas now simply correct the acid level with tartaric acid however, and no
longer practise malo-lactic fermentation.
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| The modern way: the hoops support overnight covering (foto: Consejo Regulador) |
Using the
asoleo method, the potential alcohol level in the grapes was sufficient for
stability of the wine for domestic use, but export wines needed a bit more to
withstand the rigours of a long sea journey, and were fortified as well. It was
noticed that fortification killed off any flor allowing Amontillados to be
produced more quickly, and that light fortification of Finos would save the
labour involved in sunning grapes not destined for sweet wines. Accordingly
only grapes for sweet wines are now sunned, and generally in the vineyard itself
on long sheets of polythene which can be easily covered overnight.
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| Typical PX/Moscatel hudraulic press (foto: dimobe.es) |
After two
weeks of sunning the grapes will appear much darker and will have dried out to half
their original weight, making it impossible to extract the juice in a normal
press. A purpose-built hydraulic press is therefore used onto which a “sandwich”
of esterillas and dried bunches will be placed. The hydraulic ram exerts much more
pressure, and eventually a thick, concentrated, syrupy aromatic juice flows out. This will be
allowed to partially ferment before being fortified, and after years of ageing it will be more concentrated still.
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| PX oozing from the press (foto:clubdevinos.es) |
See also: Vinification in Jerez
