Determination of Proof of Distilled Alcoholic Beverages, Using an Oscillating U-Tube Density Meter

Abstract

A simple, rapid, and accurate method is described for determining the concentration of alcohol in ethanol solutions using a density meter. With this instrument, the U-tube is suctionfilled with 0.7 mL sample, and the results are displayed on a digital read-out in specific gravity units. These values are converted by tables to per cent ethanol or proof. For samples under 40° proof, the instrument is standardized on air and water. When testing samples between 40 and 193° proof, the instrument is standardized on air and an ethanol standard having a proof within ±30° of the sample tested. Thus, large corrections for the nonlinearity of the plot of the specific gravity of ethanol vs. proof are avoided. An equation is presented that corrects for this non-linearity, and the result is obtained in per cent ethanol rather than specific gravity. Proof results obtained with this instrument are in good agreement with the values obtained by a pycnometer and/or refractometer for 1–190° proof ethanol-water solutions, vodkas, whiskeys, brandies, and liqueurs.

Combination of Refractometry and Densimetry – A Promising Option for Fast Raw Methanol Analysis

“…Densimetry, i.e., the measurement of a sample's density, is widely applied to determine the concentration of binary alcohol solutions , . However, in the case of raw methanol, dissolved CO 2 is present as a ternary component.…”

Comparison between Mid-Infrared (ATR-FTIR) Spectroscopy and Official Analysis Methods for Determination of the Concentrations of Alcohol, SO2, and Total Acids in Wine

“…The reference method to determine alcohol concentration in wine consists of density and pycnometric determinations preceded by a distillation step. Some new, inexpensive procedures are proposed, including electronic densimetry [47][48][49][50], titration methods [51], enzymatic analysis [52,53], and chromatographic methods (liquid chromatography or gas chromatography) [54,55]. However, these methods do not offer a clear advantage over reference methods and are complex, labor-intensive, and time-consuming.…”

An automatic densimeter system for themeasurement of the alcoholic strengthof potable spirits

“…Daily calibration of this instrument with alcohol and water standards is time consuming and advantage was taken of the recent introduction of the Anton Paar DMA-55 [7], which requires only air and water as references to integrate it into an improved version of the existing automatic system. The DMA-55 and an earlier *Present address: Plasma-Therm Ltd, 6 Station Road, Penge, London SE20 7BQ model have already been used in automatic systems for the examination of wines and spirits [8] and also beer [9] in other countries.…”