Öchsle scale
Encyclopedia
The Oechsle Scale is a hydrometer
scale measuring the density
of grape
must
, which is an indication of grape ripeness and sugar content used in wine-making. It is named for Ferdinand Oechsle
(1774-1852) and it is widely used in the German
, Swiss
and Luxembourg
ish wine-making industries. On the Oechsle scale, one degree Oechsle (° Oe) corresponds to one gram
of the difference between the mass
of one litre of must at 20 °C
and 1 kg (the mass of 1 litre
of water
). For example, must with a specific mass
of 1084 grams per litre has 84° Oe.
in the must. Since the alcohol
in wine
is produced by fermentation
of the sugar, the Oechsle scale is used to predict the maximal possible alcohol content of the finished wine. This measure is commonly used to select when to harvest grapes. In the vineyard, the must density is usually measured by using a refractometer
by crushing a few grapes between the fingers and letting the must drip onto the glass of the refractometer. In countries using the Oechsle scale, the refractometer will be calibrated in Oechsle degrees, but is an indirect measure, since the refractometer actually measures the refractive index
of the grape must.
. In the highest quality category, Prädikatswein (formerly known as Qualitätswein mit Prädikat, QmP), the wine is assigned a Prädikat based on the Oechsle reading of the must. The regulations set out minimum Oechsle readings for each Prädikat, which depend on wine-growing regions and grape variety:
The sugar content indicated by the Oechsle scale only refers to the unfermented grape must, never to the finished wine.
the Klosterneuburger Mostwaage (KMW) scale is used. The scale is divided into Klosterneuburger Zuckergrade (°KMW), and very similar to the Oechsle scale (1° KMW =~ 5° Oe). However, the KMW measures the exact sugar content of the must.
The Baumé scale
is occasionally used in France
and by U.S.
brewers, and in the New World
the Brix
scale is used to describe the readings of a refractometer
when measuring the sugar content of a given sample. All of these methods are similar and the differences are more cultural than significant, but all are equally valid ways to measure the density of grape must and other sugar based liquids.
The Normalizovaný Muštomer
(°NM) measures kg of sugar in 100 l of must and is used in Czech Republic and Slovakia.
Hydrometer
A hydrometer is an instrument used to measure the specific gravity of liquids; that is, the ratio of the density of the liquid to the density of water....
scale measuring the density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...
of grape
Grape
A grape is a non-climacteric fruit, specifically a berry, that grows on the perennial and deciduous woody vines of the genus Vitis. Grapes can be eaten raw or they can be used for making jam, juice, jelly, vinegar, wine, grape seed extracts, raisins, molasses and grape seed oil. Grapes are also...
must
Must
Must is freshly pressed fruit juice that contains the skins, seeds, and stems of the fruit. The solid portion of the must is called pomace; it typically makes up 7%–23% of the total weight of the must. Making must is the first step in winemaking...
, which is an indication of grape ripeness and sugar content used in wine-making. It is named for Ferdinand Oechsle
Ferdinand Oechsle
Christian Ferdinand Oechsle was a German mechanical workshop owner, goldsmith and inventor.He is most noted for developing a method for measuring the must weight of the grape must in winemaking...
(1774-1852) and it is widely used in the German
German wine
German wine is primarily produced in the west of Germany, along the river Rhine and its tributaries, with the oldest plantations going back to the Roman era. Approximately 60 percent of the German wine production is situated in the federal state of Rhineland-Palatinate, where 6 of the 13 regions ...
, Swiss
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
and Luxembourg
Luxembourg
Luxembourg , officially the Grand Duchy of Luxembourg , is a landlocked country in western Europe, bordered by Belgium, France, and Germany. It has two principal regions: the Oesling in the North as part of the Ardennes massif, and the Gutland in the south...
ish wine-making industries. On the Oechsle scale, one degree Oechsle (° Oe) corresponds to one gram
Gram
The gram is a metric system unit of mass....
of the difference between the mass
Mass
Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...
of one litre of must at 20 °C
Celsius
Celsius is a scale and unit of measurement for temperature. It is named after the Swedish astronomer Anders Celsius , who developed a similar temperature scale two years before his death...
and 1 kg (the mass of 1 litre
Litre
pic|200px|right|thumb|One litre is equivalent to this cubeEach side is 10 cm1 litre water = 1 kilogram water The litre is a metric system unit of volume equal to 1 cubic decimetre , to 1,000 cubic centimetres , and to 1/1,000 cubic metre...
of water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
). For example, must with a specific mass
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...
of 1084 grams per litre has 84° Oe.
Overview
The mass difference between equivalent volumes of must and water is almost entirely due to the dissolved sugarSugar
Sugar is a class of edible crystalline carbohydrates, mainly sucrose, lactose, and fructose, characterized by a sweet flavor.Sucrose in its refined form primarily comes from sugar cane and sugar beet...
in the must. Since the alcohol
Alcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
in wine
Wine
Wine is an alcoholic beverage, made of fermented fruit juice, usually from grapes. The natural chemical balance of grapes lets them ferment without the addition of sugars, acids, enzymes, or other nutrients. Grape wine is produced by fermenting crushed grapes using various types of yeast. Yeast...
is produced by fermentation
Fermentation (wine)
The process of fermentation in wine turns grape juice into an alcoholic beverage. During fermentation, yeast interact with sugars in the juice to create ethanol, commonly known as ethyl alcohol, and carbon dioxide...
of the sugar, the Oechsle scale is used to predict the maximal possible alcohol content of the finished wine. This measure is commonly used to select when to harvest grapes. In the vineyard, the must density is usually measured by using a refractometer
Refractometer
A refractometer is a laboratory or field device for the measurement of an index of refraction . The index of refraction is calculated from Snell's law and can be calculated from the composition of the material using the Gladstone-Dale relation....
by crushing a few grapes between the fingers and letting the must drip onto the glass of the refractometer. In countries using the Oechsle scale, the refractometer will be calibrated in Oechsle degrees, but is an indirect measure, since the refractometer actually measures the refractive index
Refractive index
In optics the refractive index or index of refraction of a substance or medium is a measure of the speed of light in that medium. It is expressed as a ratio of the speed of light in vacuum relative to that in the considered medium....
of the grape must.
Wine classification
The Oechsle scale forms the basis of most of the German wine classificationGerman wine classification
German wine classification consists of several quality categories and is often the source of some confusion, especially among non-German speaking wine consumers. The official classification is set down in the wine law of 1971, although some changes and amendments have been made since then...
. In the highest quality category, Prädikatswein (formerly known as Qualitätswein mit Prädikat, QmP), the wine is assigned a Prädikat based on the Oechsle reading of the must. The regulations set out minimum Oechsle readings for each Prädikat, which depend on wine-growing regions and grape variety:
- KabinettKabinettKabinett , or sometimes Kabinettwein , is a German language wine term for a wine which is made from fully ripened grapes of the main harvest, typically picked in September, and are usually made in a light style...
- 67-82 °Oe - SpätleseSpätleseSpätlese is a German wine term for a wine from fully ripe grapes, the lightest of the late harvest wines. Spätlese is a riper category than Kabinett in the Prädikatswein category of the German wine classification and is the lowest level of Prädikatswein in Austria, where Kabinett is classified in...
- 76-90 °Oe - AusleseAusleseAuslese is a German language wine term for a late harvest wine and is a riper category than Spätlese in the Prädikatswein category of the Austrian and German wine classification. The grapes are picked from selected very ripe bunches in the autumn , and have to be hand picked...
- 83-100 °Oe - BeerenausleseBeerenausleseBeerenauslese is a German language wine term for a dessert wine-style late harvest wine. Beerenauslese is a category in the Prädikatswein category of the Austrian and German wine classifications, and is a category above Auslese. Beerenauslese wines, often called "BA" for short, are usually made...
and Eiswein - 110-128° Oe (Eiswein is made by late harvesting grapes after they have frozen on the vine and not necessarily affected by noble rotNoble rotNoble rot is the benevolent form of a grey fungus, Botrytis cinerea, affecting wine grapes. Infestation by Botrytis requires moist conditions, and if the weather stays wet, the malevolent form, "grey rot", can destroy crops of grapes...
, botrytis, which is the case with Beerenauslese) - TrockenbeerenausleseTrockenbeerenausleseTrockenbeerenauslese is a German language wine term for an intensely sweet dessert wine-style wine....
- 150-154 °Oe (affected by botrytis)
The sugar content indicated by the Oechsle scale only refers to the unfermented grape must, never to the finished wine.
Other scales
In AustriaAustria
Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...
the Klosterneuburger Mostwaage (KMW) scale is used. The scale is divided into Klosterneuburger Zuckergrade (°KMW), and very similar to the Oechsle scale (1° KMW =~ 5° Oe). However, the KMW measures the exact sugar content of the must.
The Baumé scale
Baumé scale
The Baumé scale is a pair of hydrometer scales developed by French pharmacist Antoine Baumé in 1768 to measure density of various liquids. The unit of the Baumé scale has been notated variously as degrees Baumé, B°, Bé° and simply Baumé . One scale measures the density of liquids heavier than water...
is occasionally used in France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
and by U.S.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
brewers, and in the New World
New World
The New World is one of the names used for the Western Hemisphere, specifically America and sometimes Oceania . The term originated in the late 15th century, when America had been recently discovered by European explorers, expanding the geographical horizon of the people of the European middle...
the Brix
Brix
Degrees Brix is the sugar content of an aqueous solution.One degree Brix is 1 gram of sucrose in 100 grams of solution and represents the strength of the solution as percentage by weight . If the solution contains dissolved solids other than pure sucrose, then the °Bx is only approximate the...
scale is used to describe the readings of a refractometer
Refractometer
A refractometer is a laboratory or field device for the measurement of an index of refraction . The index of refraction is calculated from Snell's law and can be calculated from the composition of the material using the Gladstone-Dale relation....
when measuring the sugar content of a given sample. All of these methods are similar and the differences are more cultural than significant, but all are equally valid ways to measure the density of grape must and other sugar based liquids.
The Normalizovaný Muštomer
Normalizovaný muštomer
Normalizovaný moštoměr is a scale used in the Czech Republic and Slovakia for measuring the sweetness of wine must. 1 °NM indicates 1 kg of sugar in 100 litres of must....
(°NM) measures kg of sugar in 100 l of must and is used in Czech Republic and Slovakia.