Oechsle scale

Oechsle Scale is a system used to measure the ripeness of grapes with the aim of predicting the potential alcohol content of the resulting wine. It was named after its developer, a German physicist named Ferdinand Oechsle (1774-1852). The Oechsle Scale measures the density of grape must, which is a direct way of assessing the sugar content of grapes, thereby indicating their ripeness.

History

The Oechsle Scale was developed in 1821 by Ferdinand Oechsle and was officially recognized in Germany in 1898. It has since been used as a measure in the German and Swiss wine industries. The scale is based on the specific gravity of the must at room temperature, as compared to the specific gravity of water.

Measurement and Calculation

The Oechsle Scale measures the weight of the grape must (juice) in comparison to the same volume of water. This is done using a specialized instrument known as a hydrometer. The reading on the Oechsle Scale is the mass of a certain volume of must compared to the same volume of water.

The scale is calibrated so that 0 degrees Oechsle corresponds to the specific gravity of water. Each degree above 0 corresponds to 1 gram of sugar per liter of must. Therefore, a must with a reading of 90 degrees Oechsle contains approximately 90 grams of sugar per liter.

Use in Winemaking

The Oechsle Scale is primarily used in the German and Swiss wine industries to determine when grapes are ready for harvest. It is also used to classify wines in these regions, with higher Oechsle readings generally indicating higher quality wines.

In addition to its use in determining harvest times and wine classifications, the Oechsle Scale can also be used to predict the potential alcohol content of a wine. This is done by calculating the amount of sugar that can be fermented into alcohol.

See Also

• Brix (scale)
• Baumé scale
• KMW scale