Sweet wines 4 – Wines with botrytis or noble rot
December 1, 2016
In the last three posts, we’ve looked at some of the ways of making sweet wines, particularly by using extra-sweet grapes. There is one other type of very sweet grapes, which are used to make some of the world’s most sophisticated, complex and expensive wines. These are grapes affected by botrytis or noble rot.
Botrytis cinerea is a type of fungus that can devastate your grape crop in damp conditions, like rain. The fungus gets onto the grapes and, if they are wet, the fungus causes them to split open and then grey rot eats its way into them. They effectively go mouldy and smell unpleasant. If grey rot takes hold of the grape crop, they are often a complete write-off.
However, under certain very special conditions, the botrytis works very differently, creating noble rot. When this happens, the skin changes colour and texture, much of the water in the grape is lost and the sugars, acidity and flavours become concentrated. The grapes also gain unique aromas and flavours.
The process occurs at different rates among berries and clusters, so machine harvesting is out. Teams of harvesters have to make several passes (known as “tries” in France) through the vineyard, individually selecting the grapes that are ready each time. It’s labour-intensive and also you need a whole lot of grapes to make just one bottle of wine, and this is why botrytised wines are among the most expensive in the world.
So what are the right conditions for noble rot? Well, firstly you have to have the type of grapes that are liable to rot, particularly thin-skinned berries in tightly-packed bunches, such as Sauvignon Blanc in Bordeaux, Riesling in Germany and Furmint in Hungary. Next you need to have the right weather cycle, with alternating damp and dry conditions. For instance, foggy mornings to encourage the fungus, followed by sunny, breezy afternoons to dry out the grapes so they don’t split open. Achieve this pattern, cross your fingers and the botrytis will become “noble rot”.
Not very many places in the world have just these right conditions and the following are the most well-known.
Sauternes, from the Graves district of Bordeaux, is one of the most famous types of botrytised wines. Sémillon is the principal grape, as it is particularly susceptible to botrytis. Sauvignon Blanc is a common partner, adding acidity to the wine. Muscadelle and Sauvignon Gris can also be used. The conditions for noble rot don’t occur every year, nor do they affect all parts of the vineyard. If rain sets in, the grapes are lost to grey rot. Some years, there is no botrytis at all. The grapes are hand-harvested over a long period and produce tiny quantities of wine. The winemaking begins with gentle pressing and then careful fermentation, often in oak barriques and then oak-ageing. Good Sauternes is golden-coloured and extremely complex.
Tasting note: Château Guiraud Sauternes Premier Grand Cru Classé 2011, Bordeaux, France. 140 grams of residual sugar per litre. 13.5% ABV
100% botrytis-affected grapes (65% Sémillon and 35% Sauvignon Blanc) were hand-harvested and fermented in oak barrels and then aged in barrels for 18-24 months.
Medium gold in colour. Pronounced nose of orange peel, marmalade, honey, grapefruit and a herbal note. Sweet, full-bodied wine with high acidity and pronounced flavours of honey, marmalade, sultanas and other dried fruit with a caramel touch. Long finish. Very complex and delicious.
The Loire, France
Bonnezeaux is an area in the Coteaux du Layon appellation in the Anjou district of the Loire, known for producing sweet wines from Chenin Blanc grapes. Usually they will have been affected by botrytis and are likely to have also been concentrated by shrivelling or raisining on the vine (late harvesting). Chenin Blanc is a grape variety with high acidity and this is important in counter-balancing the sweetness in these wines.
Tasting note: Château de Fesles 2010, Bonnezeaux, Loire, France. 165 grams of residual sugar per litre. 13% ABV
Botrytis-affected Chenin Blanc grapes picked in 6 different tries (passes through the vineyard), matured in oak barrels for 15 months.
Deep golden, the darkest coloured of all the wines we tried at our Santiago sweet wine tasting panel. Pronounced nose of apples and pears, candied peel and nuts with caramel. Sweet, medium (+)-bodied wine with high acidity and pronounced flavours of dried apricots, pears, apples, marmalade, nuts and honey. Long finish. Beautiful, complex and concentrated and the acidity and sweetness are well-balanced, making it a refreshing wine.
Tokaj is a wine region in north-eastern Hungary which has been famous for centuries for its sweet wines. These are made of a blend of nobly rotten grapes, particularly Furmint and Hárslevelű.
I will be publishing an introduction to Tokaji wines with tasting notes shortly.
Not a major producer of botrytised wines but it is possible to find a few examples from this South American country.
Casas del Bosque Late Harvest 2014, Casablanca Valley, Chile. 214 grams of residual sugar per litre. 11.5% ABV (Half bottle retails in Chile at CLP$10,000 and at £8.59 from UK retailers like Simply Wines Direct)
This wine was made with 100% botrytis-affected Riesling grapes that were harvested very late in the season.
Medium gold in colour with pleasant aromas of stone fruit, like peaches and apricots, together with orange peel and honey. This is a sweet, full-bodied wine with medium+ acidity and a long finish. Flavours of candied peel, stone fruit and marmalade. Not quite as complex as the French botrytised wines we tried, but very good value.
Drinking botrytised sweet wines: These are wines with great complexity and concentration and will work best with richly-flavoured food, such as pâté de foie gras, goat’s cheese or Peking duck. Or you could simply enjoy a glass at the end of a good meal in place of dessert. It’ll be at its best just a little bit chilled, but try not to chill it too much, as that will just dull all those beautiful aromas.
More information about sweet wines: