The harvest has almost finished in France but in Germany's Mosel Valley, the work is just beginning. The Mosel grows many grape varieties but its forte is riesling. The simple mass-market varieties, such as sylvaner and muller-thurgau, are harvested first, followed by riesling, which most producers will begin gathering this week. There'll be no tank-tops and shorts for these harvest teams; the weather is already brisk. Riesling from the Mosel Valley is arguable the finest in the world - with neighbouring Rheingau the other contender - and many commentators argue it is the finest white wine in the world, full stop. Riesling is treasured because of its ability to produce elegant and concentrated wines across a wide spectrum of styles. At first deceptively delicate and ethereal, riesling is like a spider's web; a thin gossamer that envelops you. It is pale and green-tinged, with aromatic citrus, honeysuckle and white peach aromas lifted by a laser-focused acidity, like a beam of light shining into a room. Mosel rieslings are the wines with the lowest alcohol levels in the world, averaging 7 per cent to 9 per cent, which makes them easy to sip on a Sunday afternoon. Rarely are Mosel rieslings 100 per cent dry; producers usually leave a hint of enticing sweetness to dance with its tongue-tingling acidity. Like those from all of Germany, the wines can be bottled at various ripeness levels, with the lightest being kabinett, followed by spatlese and auslese, which always has some sweetness. Though generally referred to as the Mosel Valley, or simply 'The Mosel', in fact the region is formally known as the Mosel-Saar-Ruwer, as it encompasses wines from two tributaries of the Mosel, the Saar and the Ruwer rivers. The Mosel's climate is far too chilly for red grape varieties, though some pinot noir is grown. As Ernie Loosen, of the well-regarded Weingut Dr Loosen (weingut means 'winery') puts it, 'Growing pinot noir in the Mosel is crazy. Why use good land to grow a variety that will always be better in Burgundy? We should stick to what we are good at: riesling. Pinot noir from the Mosel sells only because it is a novelty, not because it is high quality.' The vines growing along the Saar struggle to ripen as the meandering path of the river leaves few opportunities to capture sunlight. Egon Muller is the Saar's foremost producer and he said recently that he was very pleased with the ripening so far this vintage, but warned that the final two weeks would be critical. Loosen says: 'The 2009 vintage so far looks absolutely gorgeous. We have healthy grapes, perfect ripeness and a balance between sweetness and acidity that is ideal. So, if nothing traumatic happens, it looks like a perfect vintage.' Oliver Haag of Weingut Fritz Haag agrees: 'My riesling is laughing this year.' He then asks to retract the comment. 'If I say it is a good vintage too soon, then the weather will punish me.' Debra Meiburg is a master of wine.