With the grapes harvested and brought to the bodegas the next phase begins: making wine. First the grapes are analysed for sugar content (they will need to ferment to a minimum of 10.5 % vol to be able to make Sherry), then total acidity and pH are checked. Next the grapes go into a destemming machine and on to a crusher where they are gently squeezed to make the job of the press a little easier. Sometimes some stems are left in to help the juice drain better from the pulp in the press. Great care must be taken to avoid the risks of oxidation and excess tannin. The harder you press, the more juice you extract, but the more tannic it gets, so the pressing is very carefully done. The first juice (must) to come out is called "primera yema" and accounts for around two thirds of the total extracted. This is the finest juice, low in phenolics and will go on to produce the Finos, Manzanillas and Amontillados. The "segunda yema" accounts for about 25% of the must and is more phenolic and so destined for the oxidatively aged wines, the Palos Cortados and olorosos.
Once extracted, the musts are lightly filtered to remove any solids then the pH is corrected if necessary with the addition of tartaric acid. With the acidity correct, all that remains to be done is to add a touch of SO2 (sulphur dioxide) and leave the juice - or "mosto" to settle for a day or so. Now the must is pumped to the fermentation tanks where a tiny amount of already fermenting must ("pie de cuba") is added to help the fermentation get under way.Control of fermentation temperature is less critical in Jerez than in other places, and it proceeds at about 23-25 degrees C which helps the yeast to convert all the sugar into alcohol. After about a week the fermentation comes to an end and the must is left to settle and the lees separated off. During settling a film of yeast appears on the surface of the must which is called "Flor". Malo-lactic fermentation may or may not be carried out.
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| Flor seen through the bunghole at Los Caireles (foto:pacobarroso) |
Now is the time for the first classification of the musts. They are examined sensorially and analytically, and depending on their characteristics are classified into two broad groups: those which will age biologically and become Finos, Manzanillas and Amontillados, or those which will age oxidatively and become Palos Cortados or Olorosos. Each must will be classified with a marking thus: / ("raya") /. ("raya y punto") or //("dos rayas") according to its lightness or fullness of body. After clasification, the musts will be fortified to 15.5 % vol for the biological raya and raya y punto musts, which will allow the flor to grow, and to 18 % vol for the oxidative dos rayas musts which precludes the growth of flor. The musts are now racked - transferred to clean butts - and stored. In the case of the biological musts they are called "sobretablas", and the oxidative wines are called "anadas". Both are only now referred to as "wine". Here the wine will wait for further, more precise classification before going to the appropriate solera.
These sweet wines
Meanwhile, the PX grapes which are picked at about 16 Beaume (or about 300 grams per litre (g/l) of sugar) and then dried under the hot Andalucian sun have reached incredible levels of (natural) sugar - 450-500 g/l of must! They have also dried out - raisined ("pasificada") and cannot be pressed in the same way as the Palomino. So vertical presses are used which exert far more pressure than the paltry 5 or 6 kg/cm2 used for Palomino. In order to let the (much more viscous) juice run from the pomace, the presses are loaded carefully using "esterillas" (round esparto mats) alternately with bunches of raisins ("pasas") like a huge sandwich. When the pressure is applied and aromatic honey like juice runs free. Fermentation generally starts spontaneously but slowly and the must will be fortified to about 10% vol to stabilise it. The following spring after it has settled out the solids, the wine will be fortified to between 15 and 17 % vol and filled into butts ready for the solera. These wines have higher than usual levels of tannin as the raisins cannot be removed from the stems, however with all that sugar and flavour you wouldn't really notice.
The Moscatel grapes are treated either in exactly the same way as PX, or without the "asoleo" (drying in the sun). Many Moscateles are made simply with super ripe grapes picked straight from the vine which are pressed in a normal press then fortified soon after fermentation has begun. The result is a pale golden wine, very sweet and with the aromas of fresh rather than dried grapes. It requires no ageing.
The colouring wines
These are produced in small quantities for the purpose of giving the expected colour to the blended wines such as Cream and Medium. While they contain a lot of sugar, they are not good enough as sweetening wines. Palomino grape must is boiled down on direct heat to concentrate the must down to 1/5 of its original volume and to caramelize the sugars. This liquid is called "arrope" and is also used for making desserts and as a preservative in jams. To make colouring wine, the arrope is mixed 1/3 to 2/3 with Palomino must and slowly fermented to about 8 % vol, and after settling it is fortified to 15 or 17 % vol and aged in soleras ready for the commercial Medium and Cream blends.
See also: Asoleo
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