Visiting Jerez, exploring Sherry, and blending Las Palmas
Part 3, making Sherry

Antonio Flores in action

So now it was time to look at some wines. With cellarmaster Antonio Flores, I began with Palomino Mosto from 2014.

This Mosto had finished fermenting in a barrel three weeks earlier, and it was still in the barrel. It will be left until the first cold weather, which usually is at the beginning of December, and this accelerates the natural clarification process. The wine will then be racked off its lees, and this is the point at which it is classified.

There are two routes a sherry can take: biological and oxidative, and until this decision is made all the young wines are called Mosto. This one has 11.9% alcohol, and usually the winemakers know which vineyards will give the best finos. Antonio Flores started work at Gonzalez Byass on 1st September 1980, when there will have been around 19 000 barrels in the cellar. That’s a lot of barrels to get to know. ‘The classification task was quite extraordinary,’ he says. There was a team of 5 people who visited 500 barrels a day, and their hands were corrugated by the end of the day just from the moisture of the wine.’

Over the last 34 years this process has become a bit simpler today: just 200 casks are barrel fermented, while the rest of the wine is made in stainless steel tanks before going to cask. For making fino, ‘the juice these days is from the best pagos, the lightest juice, fermented from stainless steel,’ says Antionio. ‘The process has been simplified a lot.’

Mosto Palomino, first press, 2014, from Marcharnudo
Apple notes and ripe pears, with hints of wax and floral notes, as well as some hazelnut. Fresh and textured with ripe red apples and citrus fruit. A lovely textured wine with a rounded personality. From 30 year old vines.

It’s anything but a bland, neutral wine, from low yielding old vines. At the end of December, or the beginning of January, alcohol is added. For those wines destined to be Fino/Amontillado, it is added to make the wine 15.3% alcohol, while for those to be aged oxidatively, it goes to 18%.

The idea is for Finos to take the wine to the limit of tolerance for the flor layer. It could be left to 12.5% alcohol, but then there would be a lot of competitors to the desired flor yeasts, such as Brettanomyces. The pH is around 3, and there’s very little malic acid in the grapes from the region, so there’s no malolactic fermentation. The aim is to ferment all the sugars out of the wine.

Gonzales Byass have their own private research centre, and they have been studying yeasts, which are so important in sherry production. The stainless steel vats begin fermentation with 5000 litres of wine, inoculated with their own yeast culture. Shortly after, 5000 litres more of must is added, and so on until the vat is full. This is a type of temperature control, and it also helps to keep their yeast strain the dominant yeast.

Sobretables Fino Palominio 2013
Sobretables is the name given to wine after it has been taken off its lees and fortified (Sobre Lias is when it’s on its lees). This is not barrel fermented, but rather it’s tank fermented. This is wine as racked off lees, before it has been added to the solera system, and the alcohol has already been added. Very clean, fresh pear fruit with subtle apple note. Rounded with nice warmth and texture. The alcohol is evident but it’s very attractive with a hint of saltiness. The flor is growing, but it has just a small effect because the wine is in tank.

Sobretables Oloroso Palomino 2013
Fortified to 18%, sitting in tank, not protected from air. This has a bit of orange/yellow colour and it’s nutty, raisiny and textured, with some apple notes and a bit of spice.

Flor is the magic ingredient in sherry production, because this is what enables the process of biological ageing, so important in the production of fino, manzanilla and amontillado sherries. Oxidative ageing occurs when the sherry has no flor layer, and olorosos are exclusively aged without a flor.

Many people don’t realize that fino, even despite its freshness, is an aged wine. Tio pepe is on average 4.5 years old. The biological ageing process, with a layer of yeast cells on top of the wine in the deliberately ullaged barrels, is what keeps it fresh. And, of course, there’s the solera system. These wines are made in a stack of barrels called the criadera. The solera is the lowest and last level in these barrels, where the wine is taken out for bottling. At regular periods, wine is removed from the solera, and taken to be bottled. The wine removed is replaced with wine from the higher barrels, which is younger, and the process is repeated. This blending of young and old wines is important, because nutrients from the wine in the younger barrels helps to keep a healthy flor growth.

The process of transferring sherry from different criaderas. Special devices called canoes, which fit between the barrels are used. These have a proboscis like tip that penetrates the flor and allows wine to be added to the barrel without disturbing the flor layer.

A film of the process:

Flor is the key agent in the biological ageing of sherry, and its thickness and vitality in part depends on the environment of the cellar – sherry’s second terroir. At Sanlucar de Barremeda the cellars are cooler and more humid, the flor is thicker and the Manzanillas that result have amazing freshness. In Jerez, the flor tends to be thinner. Gonzalez Byass use the warmer parts of their cellars for oxidative ageing, and the cooler parts for biological ageing.

Flor is a layer of yeast cells. This is a white/grey colour, and can be up to 2 cm thick. It consists of the same species of yeast that carries out alcoholic fermentation, Saccharomyces cerivisiae. But the races of this species that form flor are different. They fall into four families: beticus, cheresiensis, montuliensis and rouxii. Beticus is the most common, but they all have their preferred moments on the yeast film.

The flor does everything it can to survive. Fermentation removes all but a trace of sugar, and so the yeasts begin to consume alcohol, oxidising it to acetaldehyde (ethanol to ethanal, to use the modern terms). So Tio Pepe would start out at 15.3% alcohol after fermentation, the flor would consumer 0.3% of this, leaving a fino at 15%. The flor also consumes acids, amino acids and glycerol.

One of the effects of the flor is alcetaldehyde production. In Oloroso, the level might be 14 mg/litre. In Fino, it will be 340-380 mg/litre, and sometimes higher. Glycerol will start out at 8 g/litre and by the end will be lower than 1 g/litre. The reason the flor sits on top of the wine is that microbubbles of oxygen bring the yeasts to the surface.

Autolysis is an important part of the biological ageing of sherry. Yeasts at the surface produce proteins that cause the cells to adhere keeping the flor as a layer. But when the cells die the whole colony sinks to the bottom of the barrel, and then they degrade. ‘La madre del vino’ is the dead flor at the bottom of the barrel, releasing flavour compounds, and also fatty acids that help feed the yeasts on the top of the wine. The flor therefore gets nutrients from the wine in barrel, from dead yeasts and also from fresh wine added during the solera process.

This is a very old barrel from 1805: the sherry has concentrated to the point where it is no longer drinkable, but it smells amazing!

In producing Las Palmas sherries Antonio Flores is testing the limit between life and death, look to see the wine taken as far as possible by the yeasts.

Part 1, the vineyards
Part 2, Jerez and a good lunch at Aturo's
Part 3, making sherry
Part 4, blending Las Palmas
Part 5, the wines tasted

Wines tasted 10/14  
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