WSET Diploma, Week 15, Sherry PART 1

I am a recent Sherry convert and geekily enjoyed writing up these notes about my Sherry WSET Diploma class soaking up the information like Albariza soil soaks up water – more on that later (excuse the terrible Sherry analogy).
First things first, sherry is fortified wine made from white grapes which must be aged for a minimum of three years in one of three towns which make up the sherry triangle– Jerez de la Frontera, Sanlúcar de Barrameda and Puerto de Santa María – I’ll be fortunate enough to visit two of these three towns ahead of my fortified wine exam on 6^th June. Super excited!
Not all the grapes need to come from with the sherry triangle though, Pedro Ximénez grapes are often grown in nearby Montilla and then aged in one of the three key Sherry towns.
LOCATION:

Sherry is made in the province of Cádiz, Andalucia, on the Atlantic coast of South West Spain. This corner of Spain is classified as having a Mediterranean climate, it suffers extreme heat in summer and warm winters. The Atlantic moderates the climate with its cool sea breeze providing much needed humidity.
There are two key winds which impact on the area, one which is welcome the other not so. The benevolent wind is the Poniente which comes off the Atlantic and has a cooling influence and brings humidity. It provides Jerez with relatively high rainfall, around 600mm rainfall per year, much the same amount of rain as you might expect in Leicester. The rain, however, falls mostly in winter in brisk tropical style storms and after the downpour the sun comes back out.
The malevolent wind is the Levante, a breath-taking, energy sapping, hot, dry wind from the South East.
SOIL:
The very best vineyards in Jerez are planted on its famed white, chalky albariza soil, which has similar characteristics to the soil in Chablis and Champagne. This soil is key to the production of fine sherry wines and has a high limestone content. The albariza soil acts like a sponge and soaks up the rainfall from the winter storms, when the sun comes back out it forms a hard crust preventing evaporation and trapping moisture in the soil. This then filters down to the water table, which is relatively close to the surface due the gentle undulating landscape.
During the growing season, the very hot day time temperatures and the moist Poniente winds overnight combine to form a heavy dew which is soaked up by the soil. This dew provides a natural irrigation source for the vines – ensuring the vines have sufficient water to grow despite the very hot temperatures and low rainfall during the growing season.
At the peak of Sherry’s popularity vineyards expanded into lesser areas with different soil types namely Barros and Arenas soil.
Arenas is the sandy soil found around the coast, especially in the Chipiona area. It is not particularly good for Palomino as it doesn’t retain enough moisture needed for Palomino to grow properly. Moscatel does better here because it is more heat tolerant and doesn’t need as much water. Moscatel de Chipiona is a speciality from the area.
Barros soil is found at the bottom of hills and near streams, it is a rich, organic clay soil. The wines produced from grapes grown on this soil are generally thought to be coarser and so it is not is not suited to lighter styles of Sherry i.e. Fino. Much is now being vine pulled due to over production, and sunflowers and other agricultural produce are growing in its place.
GRAPE VARIETIES:

The grape of the Jerez is Palomino and creates dry or blended sweet sherries. It is a very undistinguished, kind of bland grape with a neutral character that makes Pinot Grigio seems positively fruity. This neutral base makes it ideal to take on the tertiary characteristics created during the Sherry ageing process. It has low acidity and is tolerant to heat and water stress as well as mould and rot making it perfect for the warm, humid climate in Jerez. Palomino gives high yields and has low acidity.
The high limestone content of the Albariza soil means vineyard owners will need to select a rootstock with resistance to chlorosis.
Pedro Ximenez (helpfully abbreviated to PX) is naturally sweet. The grapes are picked and then laid out in the sun on straw mats until they raisin and turn brown. They are air dried in Montilla, not Jerez, due to the lower humidity. This drying process takes 1-3 weeks. After the grapes have been dried and raisined, the grapes are popped into a press with the mats they were dried on. The mats help filter the grape juice faster and also helps stop the grapes becoming a paste.

The juice has a sugar content of up to 300g/l and so it is necessary to select a yeast tolerant to sugar. When the alcohol level gets to 5% a neutral grape spirit of 95% abv is mixed 50:50 and added to the juice. The neutral grape spirit can come from anywhere in the EU.
The wine is fortified to 15% to make it stable, at 15% and with that amount of sugar no bacteria will grow. Once fortified, the wine is shipped to one of the towns in the Sherry triangle – Jerez, Sanlúcar or Puerto de Santa María – and aged for a minimum of three years in order to be called Sherry.
Moscatel (de Alexandria) – again is naturally sweet with high levels of sugar. They are bigger grapes with thicker skins which won’t concentrate as much PX. It is made the same way as PX, dried on sandy soils or on mats, but is pressed without the mats as the grapes are bigger and juicer and so less likely to turn into a paste without the help of a mat.
Moscatel is usually blended with dry sherry to make commercial export Oloroso and Palo Cortado and is sometimes used for single variety wines.
VINE TRAINING:
The ‘vara y pulgar’ is an old, traditional way to train vines which translates as ‘thumb and stick’. The vine is trained with two branches, one is cut back to just have a couple of buds – this is the ‘thumb’, the other is the ‘stick’ which is trained to have 8 or so buds and carries that year’s fruit. At the end of each year, the stick and thumb alternates, with one year the stick being cut back to a thumb, and the thumb allowed to grow into a stick and bear fruit. This traditional way of training vines uses a Dali-esque crutch to support the stick.
This system creates better quality grapes and the alternated training of the vine helps to extend the life of the vine, which is under so much stress because of the heat. Sherry vines have a life of about 30 years tops, as high yields are required and winemakers don’t want concentrated, complex fruit character and reduced yields which come with old vines – the flavour of sherry comes from the ageing process not the grapes themselves.
The vines are trained quite low, which requires hand harvesting, and has fruit hanging underneath and foliage on top to protect the grapes from the harsh sun.
Picking vines is low-paid, backbreaking work and it is becoming increasingly difficult to find the labour.
Trials have been conducted to train vines using a Guyot system and training the vines higher, but the results have not been as good. Therefore, the ‘vara y pulgar’ system is continued but vines are being trained higher and special machines have been created to enable machines to pick lower.
THE HARVEST:
Palomino is very early ripening and Moscatel is also early ripening so the harvest is early, in August-September.
Grapes have an average sugar level of 10.5-12.5 ˚ Baume and rapid harvesting is necessary.
90% of grapes used to be hand-picked but as labour is hard to find, due to the backbreaking low-paid nature of the work, this is now closer to 80%.
In order to prevent grapes oxidising before they are made into wine, the wineries are often located in or very close to the vineyards, minimising travel time.
Specially adapted trailers have been created with large narrow trailers to carefully carry the grapes from the vines to the winery.
WINEMAKING:
First of all the grapes are put into stainless steel tanks and start to be crushed under their own weight. This free run juice is made into the finest wines – generally the finos or the best quality olorosos.
The grapes are then put into gentle pneumatic press which extracts more of the phenolics and the juice is used for oloroso or most basic cheap finos destined for a short period of ageing. The wines are classified and reclassified at every stage in the winemaking process.
The third press is not used for sherry and will be taken away to be distilled or used to create a wine designed to season oak casks or make the increasingly popular sherry vinegar.
All but couple of wineries ferment in stainless steel tanks and process all the different presses of wine separately.
There is then a two stage fermentation. First, a rapid fermentation at red wine temperatures around 22-26° degrees. Normally, for white wines you want to ferment at cool temperatures to retain the fresh fruit flavours and produce esters but the idea with sherry is to create a neutral base on which to build the tertiary flavours during ageing.
This first fermentation takes between 36-59 hours and uses 90% of the available sugar in the juice. The sugar is what the yeasts feed on and turn into alcohol.
The grape must is then cooled and allowed to slowly ferment until all the remaining sugars (10%) are converted to alcohol, this takes 2-3 months.
The wine is then allowed to settle and put into a tank 5/6 full to allow flor to develop. Flor is a natural, bready yeast which needs oxygen to survive, it creates a protective film on the top of wine to prevent it from oxidising. Natural yeasts are cultivated to create a house style. At this time the wine may be acidified, not for freshness but to protect from aectic bacteria.
When the wine is settling flor will develop. ALL dry sherry will have flor at some time. Flor will produce tiny amounts of alcohol and can tolerate higher levels of alcohol and can metabolise alcohol, using it as a source of food.
Flor likes very precise living conditions – a temperature of approx 18° C, humidity, oxygen and an alcoholic content of between 15-15.5%.
To fortify up to 16% would be to fortify for biological aging i.e. under flor, fortifying for oxidative ageing i.e. in contact with oxygen would require the wine to be fortified up to 17%. Flor dies at over 16% alcohol.
The wines are classified again with pale, light wines being made into finos and aged biologically – and heavier, darker wines made into olorosos and aged oxidatively.
NB: Only dry sherry is fortified after fermentation. Natural sweet wines are fortified during fermentation
SOLERA SYSTEM
The new year’s wine is transferred to a waiting room called a sobretabla for approximately 6-8 months. There will be a separate sobretabla for finos as for olorosos.
At this time the wines are tasted again and reclassified as necessary.
If the flor has died back and fino is too rich it may be turned into an oloroso and aged oxidatively.
The casks are very old, 50 years or more. Sherry producers never buy second hand casks and if it is necessary to replace casks, new casks are seasoned with a low quality wine from the third press designed to absorb all the oak flavour.
The solera system is a dynamic method of ageing wines which is based on a system of fractional blending of younger wines with older wines. When you take some wine out to bottle from the solera, you top up the barrel with wine from the 1st criadera, which is then topped up by wine from the 2nd criadera. The top criadera receives an injection of fresh wine from the sobratabla.
This movement speeds up the ageing process, gives more consistency producing the same taste and house style year after year.

The smallest solera is three levels – the bottom level is called the ‘solera’ itself and contains the oldest wines, above the ‘solera’ is the 1^st criadera, the next oldest wines and above them are the 2^nd criadera and so on. Soleras can be 8 criaderas deep or more if needed.
The rules say you cannot take out more than a third of stock from each barrel in the solera in one year, which is why all sherry must be aged for a minimum of three years to be a sherry.
MORE TO FOLLOW IN PART TWO – ON BIOLOGICAL AGEING VS OXIDATIVE AGEING, SHERRY STYLES AND BODEGAS