Sweetness in Austrian Wine
Sweetness, the Klosterneuburger Mostwaage (KMW), and all that stuff....
Firstly, the basics.
It is the sugar in grapes which, when the must is fermented, turns into the alcohol the wine will contain.
When all the sugar has been converted, the primary fermentation is complete.
If there is insufficient sugar to obtain the desired alcoholic strength, more can be added through a process known as chaptalisation.
On the other hand, fermentation can be terminated prior to the completion of the fermentation, leaving residual sugar in the wine. This results in a degree of sweetness which depends on the residual sugar level.
Generally speaking, the riper the grapes, the higher the sugar level, meaning higher alcohol levels may be obtained without chaptalisation.
Throughout the wealth of material published about Austrian wines, including the catalogue of wines on this website, you will see many references to KMW.
This is simply a must weight scale indicating the sugar content of the grapes at harvest time. It is used in the definition of the different quality categories. The KMW system was developed by August Wilhelm Freiherr von Babo (1827-1894), and expresses the sugar content of the must as a percentage of weight.
It can be converted to the more widely used scale, Oeschle, by multiplying by a factor of 5.
Sweetness, although it can be measured by residual sugar, is of course a sensual experience and is therefore subjective.
Most Austrian wines are quite dry. Some, particularly speciality wines such as Beerenausleses and Trockenbeerenausleses, many of which come from Botrytis-friendly regions such as the Neusiedlersee, are very, very, sweet.
Of the dry ones, there are quite a few which have residual sugar levels which elsewhere in the world would have the wines labelled "sweet", "halbtrocken", or "lieblich" - but they simply don't taste "sweet". The effect of a few grams per litre of residual sugar is to enhance the fruit in the wine, to give it extra depth, to add to it another dimension, yet which is not deserving of the term "sweet".
Sure, drink a steely dry Chablis and follow it quickly with a late-harvest Austrian Riesling with a modest residual sugar level and you may find the Riesling has detectable sweetness, but without the comparison it would not seem thus. This is mirrored in Germany, with producers such as Leitz, Hasselbach, Loosen, and Donnhoff producing this fruit-driven style of wine with residual sugar levels at the upper end of what is permissible as "Trocken" or even beyond.
I like to drink dry white wines - dessert wines apart, I would almost always plump for "dry" and yet none of the fruit-driven wines from Austria or Germany with this modest residual sugar level either seem overtly sweet or have in my view suffered. Quite the opposite - I feel this style has more flavour and is much more food-friendly, with an extra depth of flavour not always available in bone dry wines which of course have their place. So if you like dry wines, don't be put off by the thought of a modest amount of residual sugar at levels one would normally equate with wines which are not "trocken". In many cases we list in the wine catalogue the residual sugar levels.