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Aside from the density, the alcohol concentration is also directly measured with an alcohol sensor. This is carried out using catalytic combustion. In a measured stream of air, alcohol vapor rises countercurrent to the beer flowing downwards. The alcohol vapor is oxidized at the sensor and the resultant heat is measured by means of a resistive circuit. This correlates with the concentration of alcohol in the beer. According to Tabarié’s equation, the relationship between the specific gravity of beer, its alcohol content and real extract content can be calculated as follows:

\(\rho_{\text{beer}} = \rho_{\text{alcohol}} \space + \space \rho_{E_R} \space – \space \rho_{\text{water}}\)

\(\text{SG}_{\text{A20/20 beer}} = \text{SG}_{\text{A20/20 alcohol}} \space + \space \text{SG}_{\text{A20/20}}E_R \space – \space \text{SG}_{\text{A20/20 water}}\)

\(\text{SG}_{\text{A20/20 alcohol}} = 1.000\)

Volatile compounds in beer are concentrated through distillation and extracted with dichloromethane. The solvent phase is analyzed with a gas chromatograph. The linearity of the detector and the determination of the concentrations of analytes in the sample are achieved by using multiple concentration levels within the relevant range and through evaluation of the relative area under the peaks.

This method is based on the formation of a yellowish-brown, (insoluble in aqueous medium) copper (II) chelate with zinc benzyl dithiocarbamate (ZDBT), a compound that may be extracted with trichloroethane.

DMDC (Velcorin®) is used for the cold sterilization of non-alcoholic beverages. It essentially kills yeasts, bacteria and molds, with little effect on mold spores or yeast ascospores. Certain species of Lactobacillus possess an elevated resistance to Velcorin®. 

There should be fewer than 500 microbes/cm³ at the time the dosage is added. 

According to the EU guideline EG 1129/2011 [1], up to 250 mg/l DMDC may be added to flavored non-alcoholic beverages, non-alcoholic wine and liquid tea concentrates.

Dimethyl dicarbonate (Velcorin®) quickly dissociates in aqueous solutions almost completely to carbon dioxide and methanol. In addition, small amounts of ethyl methyl carbonate are formed through the reaction of DMDC with ethanol, which can be detected through GC-MS analysis techniques [2]. The  amount of DMDC added to a beverage can be determined by measuring the content of EMC and ethanol. The Velcorin® dosage can be checked by measuring the amount of methanol quantitatively using GC analysis; however, the initial amount of methanol present in the product prior to adding Velcorin® must be determined.

H₂O + C₄H₆O₅ (DMDC) → 2CH₃OH + CO₂

250 mg Velcorin  → 119.5 mg methanol + 164.1 mg carbon dioxide

C₂H₅OH + C₄H₆O₅ (DMDC) → C₄H₈O₃ + CH₃OH+ CO₂

The sugar alcohols are separated using a strongly alkaline eluent and ion exchange column and detected and quantified electrochemically using a pulsed amperometric detector (PAD).

By applying a potential, the ions are oxidized at a gold electrode and induce a measurable charge. To prevent the electrode from being occupied in a very short time, the potential is then reversed to reduce and release the ions from the electrode.

Higher alcohols and esters in beer are determined by gas chromatography using the headspace method, e.g., the volatile compounds are transferred from the gas space in the sample vial to the GC system for analysis. The method is suitable for beer brewed to any original gravity or to any alcohol content.