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Harvesting in the Priorat: Fermentation II, Pigeage, ‘Lees’, and Monitoring Fermentations

Autumn in the PrioratA friend of ours Raymond Magourty (Raymondo) is working the 2009 harvest in Priorat, Catalunya for Celler Mas Doix, a prestigious wine producer located in the village of Poboleda whose Parker Points have elevated it in popularity. With his background in wine education, and ambition to learn more about the practicalities of wine-making, the winery employed him as ‘bodeguero’ during the harvest. Raymondo will continue chiming in for the remainder of the harvest! You can also read the first part of this post about maceration & fermentation, his experience at the start of the harvest, visiting local wine festivals, the uncommon debate of when to pick the grapes and barrel topping, the theory of Unnatural Selection, and of course, typical grape varieties of the Priorat.

Saturday, 24th October

The harvest at Mas Doix ended today; no more grapes to receive. We’re all too tired to celebrate but there is a collective sigh of relief and the palpable anticipation of a return to relatively normal working days. Much of the team finish today; the daily winery tasks will henceforth be carried out by Diane, the enologist, & my good self. We manage fermentations in tank or vat and press those tanks that have finished their time on skins. I’m utterly exhausted and my hands resemble those of a coal-miner who forgot his gloves coming off a long shift – seven weeks of daily exposure to grape juice, wine and machinery have left them worn and heavily stained, especially around the fingernails. This is not unusual and most bodega employees during harvest carry similar battle-scars; some scrubbing with citric and a spell of office-work will sort it all out. Another ‘tell’ that you’re in the presence of a winemaker or bodeguero is the perfect circle of wine around the ear – this fellow has been listening to barrels that are undergoing malolactic fermentation and none of his trusty colleagues have reminded him to wash the wine away before he left.

Availing of one of the first half-days that have come my way since I arrived in Priorat, I took the Land Rover (fun) to some of the old vineyard sites where the leaves are changing colour as autumn takes hold.  The Cariñena vines change colour and loose their leaves earlier than the other varieties, you can see the streak of russet vine rows in the centre of the picture.

Fermentation II: Pigeage, ‘Lees’, and Monitoring Fermentations

I covered most of the principal methods of maceration and phenolic extraction employed at Mas Doix for red-winemaking in the first part of this post; this time I’ll examine fermentation monitoring, whites, and cover things, such as ‘Lees’, Settling, and Pigeage.

But first a quick synopsis of the key steps, in chronological order, that we go through to produce most reds at Mas Doix

  1. Pick the grapes (See post 3),
  2. Grape bunch selection (see post 4),
  3. De-stemming (see post 4),
  4. Berry selection (see post 4),
  5. Crush the berries (see post 1),
  6. Sulphiting (see post 8,),
  7. Transfer to tank (see post 6 & 7),
  8. Settling (see below),
  9. Maceration on skins (see post 6 & 7),
  10. Fermentation with skins (see post 6 & 7),
  11. Pressing (see post 1),
  12. Malolactic fermentation (see post 8),
  13. Barrelling down (see post 8),
  14. Waiting….

Punch-down (Pigeage in French)

Another important red winemaking maceration technique; despite the name this is a modest and gentle process practised by boutique or artisan wineries, in its traditional form it’s simply too labour intensive to work in larger organizations though there are those that operate a mechanized version. Basically you position yourself on a platform above the vat and wielding a long stainless steel pole with a grip at one end and a disc at the other (about 40cm in diameter), you push down on the skins, submerging them into the wine below the floating cap. At Mas Doix we performed pigeage on some 400 litre French oak barrels of old vine Cariñena and on a separate lot that we’re fermenting in a small stainless steel deposit. In the initial days of fermentation the cap of skins is floating happily on the surface over the wine but as things hot up and the fermentation becomes more vigorous the pressure of the CO2 rising from below creates a fairly solid mass floating above the wine. Not for kids this one, you need to be quite physically strong to punch-down the cap in larger fermenters. As the fermentation nears completion the cap becomes more fragile and we’re more delicate with the pigeage, it almost becomes a gentle stirring motion.

While at the excellent Limerick Lane in Sonoma, California we ‘punched-down’ up to 10 actively fermenting vats of up 3000 litres four times daily. On one or two (I’m recollecting the dreaded thick skinned Syrah) the cap became solid enough to support considerable weight and we had to use poles with footholds to push with all our body weight into the cap. At the end of the fermentations, at around week 4 or 5 I was feeling somewhat the worse for wear but had developed lots of upper body strength and shed a few unnecessary kilos into the bargain. We had a 2.5 metre wooden plank centred above each tank and myself and my German colleague, Levin would work side-by-side but facing opposite directions and operate on the opposing semicircles of the same tank. Not quite ballet but very efficient and a new approach that we initiated but failed to patent – previously it had been one person per tank. It frequently occurs that while over-exerting themselves, someone looses their balance and topples into the vat, for this reason we never punched-down unaccompanied.

‘Lees’, & Settling

During the fermentation process for both reds and whites ‘Lees‘ are produced; sediment precipitates to the bottom of the fermentation vat composed of dead yeast cells, pulp, seeds, bits of skin fragments and insoluble tartrates. For whites ‘Settling’, to allow the lees time to precipitate, is undertaken prior to fermentation, for reds it’s afterward.

Right throughout the winemaking cycle up until bottling lees are deposited on the bottom of the vessel containing the evolving wine and we carefully ‘rack’ to separate the wine from it’s lees.

The lees are a thick, heavy, viscous substance and once separated from the wine are transported in drums back to the vineyards where it is recycled in the form of fertiliser, providing a useful source of Nitrogen and Potassium to the soils.

Fermentation Monitoring

There now follows a spot of winemaking 101.

Fermentation is the process that the ‘must’ undergoes to produce alcohol and make wine. Basically the yeasts, be they native or cultured, feed on the sugars, which comprise most of the grape, and convert them to alcohol producing CO2 and heat in the process. Yeasts operate aerobically (in the presence of oxygen) or anaerobically (in the absence of oxygen) but only produce alcohol in the anaerobic state.

So, in the absence of O2: Yeast + Sugar = alcohol + CO2

The quantity of sugar present will yield about half its weight in alcohol and the remainder as CO2, a colourless, odourless but dangerous gas that must be managed carefully in the winery.

In simple terms it takes about 17g of sugar per litre of alcohol to produce 1% alcohol by volume. The fermentation rate and temperature are closely related, the higher the temperature the faster the fermentation.  We ferment the reds between 22ºC and 28ºC predominately in stainless steel. All vats are temperature controlled and equipped with temperature dials. We monitor the fermentation on each vat several times daily, checking 4 critical elements:

(1) Temperature,

(2) Must density for sugar remaining,

(3) Aroma or smell,

(4) Taste.

The first two require a few simple winemakers tools: a small narrow plastic sample tube and density metre, an accurate thermometer, and tissue for mopping up any spills. The later two require experience, craft, concentration and ability.

Another way to explain what happens is to go through the steps for a single wine. …reaches below counter or into the oven….”Here’s one we made earlier”:

We harvested Cariñena Vieja (Old Vine Carignan) from our sites (‘Domenech’, ‘Rober’, & ‘Salanca’) on 14th October and the next day, after rigorous selection, the fruit was crushed and transferred to tank, yielding appro 4,700 litres of must (Juice, skins). We also put a further 600 litres into two large first-fill French oak barrels and a further 400 litres into a separate stainless steel deposit for a spot of experimentation! The must density starting point for the tank was 1107 g/l and the must temperature was 17ºC. The fermentation began the following day and on the graph below you can see that as fermentation proceeded the density falls as the temperature rises and peaks before stabilising. We performed Remontage/pump-overs (See post 6) twice daily on the vat, varying duration, technique and aeration throughout the fermentation lifecycle. On the barrels and stainless steel deposit it was old school pigeage.

Through daily measurement of the density and temperature it is possible to graph, as we do for all fermentations, the fermentation progress. It’s in Catalan my friends/amics/amigos/amis.

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You can palpably sense a prickle in the mouth when you taste fermenting must and the old vine Cariñena, as it looses it’s juicy sugariness, begins to tastes of ripe cherry, pressed olive oil, black olives and whatever else your imagination and taste buds tell you. The winemaker’s role at this point is to allow the process to run its course, intervening as little as possible, while checking for any abnormalities, reductiveness or off-flavours rather than produce a lexicon of tasting terms.  The graph charts the progress of the main tank from juice to wine, demonstrating the correlation between temperature and density – the blue line represents the falling must density, the red plots the temperature changes.. The fermentation lasted ten days after which the wine remained in contact with the skins for an extended maceration of about a further 3 weeks. We then separated the wine from the skins and lees and pressed the skins, of which more next post.

White winemaking at Mas Doix

White and red winemaking processes are quite different and as both Priorat in general and Mas Doix specifically produce around 97% red, that’s where my focus has been for the winemaking side of things. But here’s a brief note on how we make the whites:

The key differences are that the whites see no skin contact after crush and are fermented at lower temperatures (12ºC – 17ºC) with less aeration. The understated process of chilling the white grapes overnight prior to crush aids the release of aromatic compounds contained in the cells under the skin. Next day, we gently crush the grapes whole cluster without de-stemming then press immediately, releasing the must, which is then transferred to fermentation vessel.

Once the fresh must is in tank we allow a period of ‘Settling’ (Debourbage in French), pre-fermentation to facilitate the precipitation of heavier particles to the bottom of the vat. Usually this is around 12 – 16 hours, during which the vat is cooled so that oxidization and bacterial activity is prevented.

We fermented the Pedro Ximinez (PX) in tank at around 16ºC and after a few days we racked the wine off its ‘lees’. We barrel fermented the Garnacha Blanca at between 15ºC and 18ºC and performed a little bâtonnage; (French term meaning Lees stirring – See photo above) on the deposit of ‘lees’ that developed on the bottom of the barrel. We do this by inserting a stainless steel pole into the bunghole, and stirring to mix the cells with oxygen and enhance the flavours. This yields a rounder mouth feel with a certain softness that, when not over done, is very pleasing. We’ll blend the PX & Garnacha Blanca in the spring to produce a light, fresh, lively white to accompany food with about 13% alc. It’s an uncomplicated style that isn’t going to take over the world but the results thus far during evolution of the wines are very promising and demonstrate balanced acidity with citrus and pear notes.

Check out more photos here. Next post I’ll cover pressing and more besides. Nearly there and fairly tired, I must say!

All the best.

Raymondo

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  • charlie

    Considered replacing your wine punch-down (pigeage) with the pneumatage process instead.

    It’s by far the the best way to automate your cap management and efficiently aerate your must during fermentation to eliminate the formation of hydrogen sulfide and mercaptans.

    Best of all, there are no moving parts and no need to sterize or clean the equipment afterwards each pump-over. You can also turn the caps in mulitple tanks at the same time.

    http://www.pneumatage.com/

    http://vimeo.com/6594151