With the delay of the onset of botrytis, which did not arrive until mid October at the same time as the wet autumnal weather inevitably, many smaller producers produced non-botrytised sweet generic Sauternes and dry wines this year. When the botrytis finally arrived its development has often been stopped by many rain showers which also encouraged the development of botrytis gris and not noble rot which concentrates the sugars by dehydration rather than turning the grape into a hollow grey husk. Here are some photos around Bommes and Sauternes of the many grapes still on the vines taken this weekend 3/4 November 2012.
You can see clearly the fungus mycelia on the grapes which puncture the grape skins and allow the water to evaporate. Most of the grapes are here at the ‘pourri plein’ stage now they just need to dehydrate and shrivel up!
Notes on Botrytis Cinera; it is the climatic conditions of misty mornings and dry sunny afternoons that dehydrate the insides of the grape (that elsewhere rots the grapes) and enable the grape to continue it ripening process and ripen completely. The mist is caused by the warm waters of the Ciron (whch originates from a spring) joining the warmer Garonne River. Wherever noble rot ocurrs in the world (Tokaji, Loire, Germany etc) the element of water is what creates these unique conditions.
The spores do not arrive uniformly and affect the grapes within a single bunch differently so the grapes need to be harvested selectively. Pickers need to be expert and pick berry by berry going through the vineyard several times (tri) to identify the pourri roti or confit (shrivelled and furry!). Labour costs are very high.
Fermentations are often slow and difficult due to the high sugar levels and botrytis which inhibits the action of the yeasts further. Yields are very low (one glass per vine instead of 1 bottle for red wines) and pressings (performed immediately) are difficult and long. Yet prices for these wines remain reasonable.