Rudolph Research Analytical - Alcotest

The Problem – Efficiency, Regulation, and Taxes

Alcohol manufacturers operate in a competitive world. They must keep costs under control and keep production operating efficiently to ensure profitability. Alcohol producers have all the demands of manufacturing a constant product with the added burden of making a product that must comply with government measurement and labeling guidelines. In most countries, the production of alcohol is highly regulated, tax reporting must be accurate, and manufacturers must report correct % ABV values. Government-prescribed measurement methods can be very slow and require laboratory skills to produce an accurate measurement. Rudolph addresses the need for alcohol producers to make fast, accurate measurements at various stages during the production process. Rudolph also addresses government requirements, by providing certified instruments that will keep your production facility in full compliance.

Alcohol Testing Solution

The AlcoTest®RI offers a certified government-compliant method and a rapid non-certified method to read % ABV. Certified results can be used for taxation purposes and will serve as the benchmark method. Using the “Production Method” you can measure alcohol content, without distillation, and also read the sugar content which is the source of most obscuration in flavored alcohol beverages. It just takes a few keystrokes to move between the certified Government Compliant Method and Production Methods.

Principle of Operation

Regulatory method – Vodka and similar products. Vodka is a mixture of alcohol and water. The density of water and alcohol are well known, so the user simply measures a sample in the density meter and the measurement display shows % ABV. Different countries use different scales and even different expressions of the same scale. AOAC ABV is used in the USA, OIML ABV is used in Europe, the UK uses Proof, Canada uses ABV, and the Japan Taxation Department uses AOAC Proof. These are just a few of the many scales that can be used to present % alcohol.

Regulatory method – Other Products. The difficulty with many alcohol products today is that other ingredients besides alcohol and water are included in the final product. These other ingredients are important because they add unique tastes and aromas with improved “mouth feel”. The consumer likes these additional ingredients which are generally sugar and flavorings but they obscure the % alcohol and alter the density measurement. The USA TTB solution is for the user to distill the sample before measurement in a density meter. This distillation process is time-consuming and can take as long as 2 – 3 hours according to the US TTB. At the end of the process, the user has an alcohol-water mixture which they can measure in the density meter in the same way they would measure straight alcohol. Accuracy in regulatory mode is dependent on the model of density meter that the Alcotest-RI® is built around.

Production Mode – Other Products In Production Mode, the Alcotest-RI® also measures the refractive index. Refractive Index (RI) is a proven measurement used to estimate the amount of other ingredients in the sample and correct the density meter measurement for their effect on the % alcohol value. Production Mode allows a user to obtain a result in less than 2 minutes with no sample pre-treatment. Accuracy in Production Mode is sample-dependent but is often comparable to the results obtained using a standalone density meter and distillation step.

Alcohol Beverages and Related Applications

High Proof Spirits including Bourbons, Straight Spirits, and Flavored Spirits

Manufacturers of spirits are generally subject to the highest tax rates and benefit the most from the use of the AlcoTest®RI. With the recent explosion in the growth of flavored or obscured spirits, the ability to make specialized methods for each product will mean that the number of distillations a lab needs to do can be dramatically reduced. The AlcoTest®RI is the perfect solution to help with this. Instead of making 2, 3, or even 4 distillations on a batch of flavored products, the AlcoTest®RI can reduce that number to one.

The AlcoCalc® option allows the AlcoTest®RI to be used for calculating dilutions of alcohol and water solutions. The AlcoCalc® feature will automatically calculate for you the amount of water to dilute a high %ABV solution to the desired %ABV based on known tables, or how much alcohol to add in order to recreate the %ABV. This is generally the preferred configuration for distilleries and many flavor companies. It is the least expensive configuration and uses the lowest sample volume. It also allows the measurement of extremely viscous or rheopectic samples which can be important in flavor companies


There are many, non-approved, quick methods for wine analysis. While wine alcohol content is often not as critical for wine as it is for spirits there are still regulatory requirements. Depending on the country there may be a point above a certain alcohol level that the tax rate changes (16.0 % ABV in the USA). A winery must use an approved method when they are producing a product near that point. Some of the non-approved methods are geared more toward measuring other components in wine and may provide % ABV but not with the accuracy available with the Alcotest®RI.


The last decade has seen a large expansion of different types of beer being brought to market. Being able to accurately control the brewing process is the key to moving from hobbyist to a profitable brewer. The AlcoTest® Determines: • Original Extract • Apparent Extract • Real/True Extract • Alcohol by volume • Alcohol by weight • Real Degree of Fermentation • Real Attenuation • Apparent Degree of Fermentation / Apparent Attenuation

Ready to Drink Alcohol

Many very successful soft drink manufacturers are expanding into ready-to-drink alcoholic beverages. Beverage companies traditionally focused on monitoring Brix, but this value is now obscured by alcohol. The correct Brix value in their soft drink manufacturing process can be maintained by correcting for the alcohol in the product obscuring the measurement. The Alcotest®RI solves this problem, by measuring the Brix value as if no alcohol were present.


Alcohol Beverage Manufacturer

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