With the grape harvest out of the way and the nights slowly drawing in, it’s easy to think that winemakers are sitting around twiddling their thumbs. Nothing could be further from the truth. Outside in the vineyard, the vines may be bedding down for a period of rest and regeneration, but inside the winery, it’s all action.
The first challenge is to kick-start the fermentation process so that all those naturally occurring yeasts convert the grapes' sugars into alcohol. To help that along, grapes usually go through some kind of destemming and crushing process. This breaks the skin a little, which boosts the contact between grape skins and pulp and helps the yeasts get working on the grape juice. In the case of white wines, the juice is usually separated from the solids before fermentation. But with red wine, the grape juice and pulp are generally fermented together.
In either case, the juice (or 'must' to give it its proper name) is now pumped into tanks to ferment. These tanks are usually made of stainless steel, but you can ferment wine in all sorts of materials from clay amphora to wooden barrels. Once the liquid is inside the tank, the winemaker needs to slowly increase the temperature, prodding the yeasts into life so that they can get to work converting those sugars into alcohol. For red wine, the optimum temperature is generally between 25 – 30ºC. Whilst for whites, it’s between 16 – 20ºC to help preserve the more delicate aromas of the fruit.
With fermentation underway, the next job for those who are making red wine is something called ‘cap management’. During fermentation, carbon dioxide is produced which forces the solids to float up to the surface and form a cap. But red wine gets its colour and a lot of its flavour from compounds in the grape skins called phenolics. This means it’s important to keep all the liquid in contact with those skins so the phenolics can leach into the liquid.
Punching down means physically pushing the cap back down into the liquid and mixing it all together again. These days this is usually done using a long pole with a flat disc at the end. But in times gone by, when wine was fermented in open-top wooden vats, it was quite common for the winemaker to climb into the barrels and stamp down the grapes with their feet. One or two winemakers still do this, even using their hands if they’re working with smaller batches. But it’s a bit impractical if you’re making lots of wine.
Punching down by hand
The alternative, pumping over, involves pumping off juice from the bottom of the fermentation tank and spraying it back in at the top to wet the cap and encourage that all-important contact once more.
The frequency with which punching down or pumping over happens depends on the result the winemaker is looking for, as well as the overall fermentation time of a particular wine. But it can be up to several times a day – so the winemaking team are kept busy while the wine is fermenting.
We said this is a job specifically for red wine. That’s because white wine is fermented as just liquid, with no grape solids in the mix. So, a cap doesn’t form and there is no need for that process. So, apart from keeping an eye on the temperature, winemakers can leave white wine on its own to quietly ferment away.
What happens next varies a lot from bodega to bodega. For Rosalía Molina, owner and head winemaker at Altolandon in DO Manchuela and creator of Rayuelo, this week’s Wine of the Week, the autumn is about “getting all the wines prepped for the next stage (…) ready to get the wines that are going to be oak-aged into the barrel, the amphora-aged wines into amphora and so on.”
Rosalía Molina, owner and chief winemaker at Altolandon
This is also a time for experimentation and discovering new things. So in October at Altolandon, the bodega is full of microvinificaciones, or smaller fermentation tanks with test batches of wines which might include new grape combinations or different winemaking techniques. So she has plenty of smaller projects to keep an eye on.
Of course, not everything happens in perfect synchronicity across the country. Spain is a land of contrasts. In places like the Canary Islands, Montilla-Moriles in Cordoba or the Marco de Jerez harvest might be done and dusted by the end of July. Whilst in higher, more inland regions like Aragon teams might still be bringing in the grapes well into October.
But whatever their individual timetable, harvest time is not the end of the season by any means. It’s simply the start of the next – and some would argue most important stage – in the winemaking process.