If you want to ascertain the sugar-content of the grape-must, you will need an appropriate instrument.

The must-refractometer of Mr. Oechsle

Wherever in autumn friends of wine are sitting together, they'll have one thing to talk about for sure:
"How much degrees Oechsle does the wine have this year?" Than they are going to talk about it like experts and often they start to bet about it. Oechsle is the name of an old gold-smith- and mechanic-family who lived in Pforzheim during the times of Napoleon.
Ferdinand Oechsle and his son Christian Ludwig were both great connoisseurs of wines and they were always annoyed that they only could anticipate but not measure the quality of wine-must.
In that case they found out that the fruit-sugar-content correlates directly to the quality of wine. Thereupon they concluded: "If you can measure the sugar-content of must than you´ll be able to foretell the quality class of wine."
Both of them started to develop an instrument to measure the so called "must-weight". The result was similar to a thermometer swim- and subsidence- wage which is unchanged in its basic design to this day and it's called after its inventors.

Function of a must- refractometer:

The must- refractometer is based on the fact that sugar is heavier than water. The organization of measurable degrees is going out from the specific weight of water. In case the must-weight is 80 degrees Oechsle, than the specific weight of the must is 1080. So the must consists of 17% sugar. After the fermentation the wine contains about 80 grams of pure alcohol per litre.
Now you'll understand the emotion of the connoisseurs of wine in autumn.

Therefore the winegrower is very interested in how many degrees Oechsle his must is possessing because the resulting wine is his reward for the hard work he had to do over the year.

Must-weight and wine-quality

In general the must-weight of a middle-aged vintage in Germany lies between 70 and 80 degrees Oechsle. The must-weight of wines made from late-gathered grapes is higher and is, according to the area under cultivation and the vine-sort, exactly prescribed. Wine made of the choicest grapes are starting between 90 and 130 degrees Oechsle. Absolutely choice wines are going to reach up to 200 degrees and higher.
To judge the quality of a vintage only by must-weight would be too simple and unilateral.
The Oechsle degrees are just a measure to estimate the prospective alcoholic strength. The taste of wine, its flavour, fruity acid and its bouquet is not even sloping of it.
Considering something vivid like wine, you'll have to follow many factors which are decisive for its quality for example its age.

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