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Through heating and shaking, the gases contained in beer are collected in a burette filled with potassium hydroxide. The carbon dioxide is bound by potassium hydroxide, and the remaining volume of gas, consisting of oxygen and nitrogen, is measured [1].

The quantity of soluble dry matter is determined refractometrically. This is related to the percent by weight of sucrose in an aqueous sucrose solution, which under defined conditions possesses the same refraction index as that of the product being analyzed. The amount of soluble dry matter is expressed in g per 100 g of solution. The refraction index is not determined directly for non-alcoholic soft drinks, but rather by means of a scale based on the percentage of sucrose by weight (°Brix). Since the °Brix scale uses sucrose, correction factors for other sugars must be taken from tables for each individual type of sugar. The presence of other substances, such as organic acids, minerals and amino acids, has an effect on the refraction index of a product. Due to the high acidity of citrus juices and citrus juice concentrates, correction factors are also necessary for measuring their °Brix values.

The fruit juice content of beverages and soft drinks is a very important quality characteristic. In Germany, there are guidelines that define the amount of juice contained in fruit-based beverages and soft drinks.

The guidelines specify that beverages made with fruit juice from seeded fruits or grapes must contain a minimum of 30 % juice, while those made from citrus fruits must contain at least 6 %, and beverages made from all other fruits or fruit combinations must contain at least 10 % juice. At least half of the juice content specified for fruit-based beverages must be present in fruit-flavored soft drinks. 

Under special conditions, a high fruit juice content can also be determined. In order to evaluate these conditions, equations for calculating the juice content have been developed by the working group for fruit juices and fruit-flavored beverages within the Society of German Chemists.

The RSK values serve as the basis for the calculation and are used to aid in the evaluation for evaluating the authenticity of fruit juices and products made from them (the values are not legal standards).

The different levels of importance attributed to individual analytes and, in part, the large range of fluctuation typical of certain values, were taken into account by assigning a weight to the value for each analyte in the equation.

The organic acids are separated using two combined columns, reversed-phase HPLC and an ion exchange column and are then determined using a UV detector.

The measuring principle of the micro viscometer is based on the Höppler "Falling Ball Viscometer". A sphere of known dimension rolls through a closed capillary inclined at a defined angle. Inductive sensors detect the ball over a precisely defined distance of approx. 100 mm or 25 mm. The rolling time is measured by the device and used for dynamic viscosity calculation. The temperature is precisely controlled by thermoelectric Peltier elements and checked by a Pt100 temperature sensor. A temperature accuracy of ± 0.02 °C and a repeatability of ± 0.005 °C can be achieved.

Hop constituents are distributed between an aqueous acidic methanolic phase and diethyl ether. Hop bitter substances extracted with ether are subsequently separated according to their different solubility properties in cold methanol and hexane into fractions: total resins, soft resins and hard resins. The soft resins are further separated according to their capacity to form complexes with lead salts into α-acids (conductometer value) and a β-fraction.