Julie Harrison - Sweet Wines

Sweet wines have a bad reputation often stemming from unpleasant experiences of very average sweetish wine in our formative wine drinking years. The reality is that a good sticky is one of the most delicious wines around.  Ignoring the sweet fortified wines such as port just how are good sweet wines made?

There are key varieties that are best suited to sweet wine production including Muscat, Riesling, Gewurztraminer, Chenin Blanc, Semillon, Sauvignon Blanc and Muscadelle. Sweet wine making is based on the fermentation ceasing before all the sugar has been gobbled up by wine yeast.   Some varieties like Muscat (Moscato/Moscatel) ripen easily and are naturally high in sugar so you get a good level of alcohol in the finished wine while still having plenty of residual sugar left over.   The other way of making very rich sweet wines is by using extremely ripe, concentrated raisinated grapes. These are often described as “late harvest” as the grapes have been left hanging on the vine as long as possible for maximum shrivel and concentration of sugar. Sometimes these grapes can be infected by the fungus Botrytis cinerea. This fungus is the key factor behind some of the greatest sweet wines of the world notably the wines of Sauternes, home of the famous Chateau d”Yquem, the sweet Rieslings of Germany and Tokay from Hungary. Under the wrong conditions this fungus results in a mouldy mess described as grey mould, however when conditions are just right it transforms into noble rot and the results are delicious. The fungus grows on the skin of the grape making it more porous, allowing water to be released from the pulp. The mould causes complex changes in the chemistry of the grape altering its flavour profile and increasing the level of viscous glycerol. The result is a lusciously sweet golden wine with ginger, stone fruit, toffee, marmalade and honey notes. Making late harvest wines is a labour of love and can be very risky. Leaving the grapes on the vine well into autumn runs the risk of everything turning to mush if the weather turns bad. Grapes are hand picked selectively as they will vary in “shrivel” and “ripeness” with pickers combing the vineyard for perfect fruit. With such shrivelled fruit you do not get much juice from a bunch of grapes and the makeup of the juice means that fermentation is often a long and difficult process.

The Germans are famous for Rieslings both dry and sweet. If you want to try a sweet German Riesling look for (in increasing order of sweetness), wines labelled Spatlese, Auslese, Beerenauslese and Trockenbeerenauslese. Beerenauslese and Trockenbeerenauslese are particularly rich and will have Botrytis influence.   Ice wine/Eiswein, made in cold climate regions like Germany, Switzerland, Austria and Canada is another type of sweet wine made from Riesling or Vidal. This is an extreme example of “late harvest” with grapes being left on the vine until they freeze. They are hand picked in the middle of the night in freezing conditions as it is important that the grapes do not defrost. The frozen grapes are pressed resulting in a viscous, rich, honeyed wine that still has good acidity due to the grapes been grown in a cold climate region.

Drying grapes after harvest to produce sweet wine is a common practice in the Southern Mediterranean with harvested bunches of grapes being dried on straw racks in the sun or hung from a rack or roof. These wines include the Passito wines of Italy and Vin Santo from Greece and Italy and Vin de Paille from the Jura region of France.

New Zealand produces some excellent late harvest wines which are well worth trying. Do look for one that has some Botrytis influence as the flavour of wines infected by this fungus is delicious. They match well with blue cheese and are also great to savour on their own instead of dessert.