December racking

Until the month of December, it can be said that Rioja wine is not completely fermented, whether it is red, white or rosé. When the wine is devatted, it is still sweet. Later, it slowly begins to lose sugar through controlled fermentation until it becomes "dry", in other words, without a sweet taste.

When Rioja wines are dry, they still contain one or two grammes per litre of sugar, but this is normal and does not cause problems of taste or stability.

Until December the yeast lives in the wines, consuming sugar. Then, the yeast dies and falls to the bottom of the tank. This is helped by the month'cold temperatures. It is said that the wine clears. Theoretically, it is now ready for consumption, but the yeasts which fall to the bottom of the tank together with insoluble tartrate crystals or very small vegetable particles are very rich in nitrogen and vitamins. In addition, the dead yeast can break up and release yellowish colour into the wine.

We must remember that dead yeast in a 25,000-litre tank of wine can mean a thousand litres of organic matter. If racking is done early, the dead yeast having been abrecently deposited, the wine has a hard, acid, fruity taste; but is a fresh and fruity aroma, perhaps a little rough. On the other hand, by putting this separation off until January, as Rioja wineproducers recommend (until the first full moon of January), the yeast may have broken up. Bacteria grows among the yeasts and the colour of the wine is less vivid; the wine less acid, less fresh and fruity with a tendency towards indistinct odours and tastes.

We might ask the following question: What has the moon to do with December racking, bearing in mind that it is typical in the Rioja for wineproducers to rack at the first full moon in January? We can offer two explanations. One of them is that the first full moon usually coincides with high atmospheric pressure. This means frost and the wine is cold. However, we understand that many farming operations show that during the life cycle of moulds and fungi, such as yeast, some phases of the moon stimulate their growth and activity while others have the opposite effect. It is possible that Rioja wine producers have detected over the centuries that in specific phases of the moon the activity of yeast is very limited and offers a good opportunity to separate a large amount of clean wine.

The dirty sediment, separated in this racking operation, is called lees and is a liquid very rich in organic matter. It is usually channelled to the tartaric acid extraction industry or for the recovery of alcohol, through the "obligatory wine delivery" system.