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Unit for displaying the Relative Density or the specific weight of Grape Which is the mass (weight) of the must in proportion to its volume. This is also referred to as extract mass consists of the solutes in the grape, where mainly share Sugar (Fructose, glucose). The specific weight of the grape is always greater than 1.0 (water), the difference arises mainly from the sugar content. The difference "of a certain volume of must weight" to the "weight of an equal volume of water" is called weight ratio. Most of the weight, the possible Alcohol content be derived from the wine (theoretical) complete fermentation of the sugar. To calculate complicated formulas are needed, so in most cases, tables are used. The measurement is performed with Hydrometers (Hydrometer) Pycnometer or Refractometer (Refraction). There are various methods and measures:
KMW = Klosterneuburger scale: the procedure was from August-Wilhelm Freiherr von Babo August-Wilhelm (1827-1894) in 1861 on Klosterneuburg Viticulture Institute based on the Carl Joseph Napoleon Balling (1805-1868) invented Saccharometers developed. This unit is common, especially in Austria, Hungary, Italy and former Yugoslavia. The KMW-scale is usually calibrated to a temperature of 20 ° C. The exact translation of KMW KMW in Oechsle = x (4.54 x 0.022 plus KMW), or roughly KMW x 5 The conversion formulas of KMW degrees in alcohol content and are a rough estimate only 16 to 21 ° KMW fairly accurate:
* 1 ° Brix = 10 grams or 1% sugar in 1000 grams must
* 1 ° KMW corresponding to 4.98 or 0.65 Oe ° Bé (KMW / 1.53)
* (KMW - 4) x 0.85 =% alcohol by volume for white wine
* (KMW - 4) x 0.80 =% vol alcohol in red wine
Oe = Oe: That the German optician and jeweler Christian Ferdinand Christian Ferdinand Oechsle (1774-1852) developed in the 1820s, or procedure that bears his unit is in use mostly in Germany, Luxembourg and Switzerland. The Oechsle scale is usually calibrated to a temperature of 17.5 ° C. A degree Oechsle (Oe) is defined as the weight increase of 1,000 milliliters Most to 1 gram a liter of 50 ° Oe must therefore weighs 1050 grams, the potential alcohol content in grams per liter is roughly equivalent to the degrees Oechsle.
Bx = Bx: That the Austro-German scientist Adolf F. Brix (1798-1870) in 1870 developed method and the unit of measurement named after him is common, especially in English speaking countries. A liquid with n degrees Brix has the same density as an n-% sugar solution (ie, n grams of sugar in 100 grams of sugar solution). The sugar solution serves as a reference to the density, Brix degrees therefore specify (such as Oe) is not the right proportion of sugar. While the direct measurement of the KMW putative sugar-free extract is removed and therefore (approximately) will indicate the proportion of sugar in weight percent, of sugar-free extract in the determination of the Brix level is still contained. Most has therefore about 3.5 ° Brix degrees more than ° KMW (at 20 ° KMW, the difference is smaller for small and larger at high must weights). The unit also used in English speaking countries Balling is almost identical and is often expressed as "Brix-balling".
Bé Bé =: Designed by the French chemist Antoine Baume (1728-1804) developed the method and named it after his unit is in use mostly in Mediterranean countries including France and Australia. Thus, the total dissolved solids in the grape and measured so that the approximate amount of sugar. The Baume degrees correspond almost exactly to the potential alcohol content.
The table shows the relationship of the individual units, depending on specific gravity (SG) and alcohol content (PAG). However, you can only have complicated formulas are converted into each other, because the relationships are not linear with each other. Therefore tables are often used. As a rule of thumb that 10 grams of Sugar by the Fermentation 0.66% vol Alcohol content result, which means vol consists of 16.5 to 18 grams of sugar about 1%. In general, white wines are at the bottom and red at the top end. In grape must contain: 70 to 85% water, 12 to 27% sugar, 0.3 to 1.5% Acids , To 0.2% Tannins and up to 0.2% nitrogen.
SG 1.060 1.065 1.070 1.075 1.080 1.085 1.090 Oe 60 65 70 75 80 85 90 KMW 12 13 14 15 16 17 18 Be ' 8.2 8.8 9.4 10.1 10.7 11.3 11.9 Bx 14.7 15.8 17.0 18.1 19.3 20.4 21.5 PAG 8.2 8.8 9.4 10.1 10.7 11.3 11.9
SG 1.095 1.100 1.105 1.110 1.115 1.120 1.125 Oe 95 100 105 110 115 120 125 KMW 19 20 21 22 23 24 25 Be ' 12.5 13.1 13.7 14.3 14.9 15.5 16.0 Bx 22.5 23.7 24.8 25.8 26.9 28.0 29.0 PAG 12.5 13.1 13.7 14.3 14.9 15.5 16.0
The Frenchman Victor Victor Pulliat (1827-1896) developed end of the 19th Century, a classification for the classification of the varieties in terms of their Maturity date and defined as the comparison criterion must weight. In Germany and Austria is the must weight is an important quality criterion by which a wine is classified already own it. It has also been awarded the Official test number (D) or State control number (E) is important. In the two countries, it is but a little too highly valued, because there are other important criteria.
In the warmer wine regions, the must weight is not very meaningful. The read time is determined there therefore after the acid values. Because of the content Acids , The pH value and the Total extract play an at least equally important role. In recent years, the term physiological maturity was to achieve the Maturation (Maturity) takes into account the grapes far more comprehensive. From August 2009 to the current EU wine market is now the criterion Origin uniform with respect to high importance to wine quality levels, see below Quality System .