Detection of harmful yeasts and bacteria by means of membrane filtration and subsequent incubation on OFS agar.
All clear beer-based beverages and lemonades.
The sample is membrane-filtered, incubated and analysed.
Detection of fermentable yeasts and bacteria using a pour plate after prior liquid enrichment.
All cloudy beer-based beverages and lemonades.
The sample, which has been pre-enriched in SSL broth, is suspended in culture medium (OFS agar), incubated and analysed.
The method describes alternative culture media to OFS agar and SSL broth.
All beer-based beverages, lemonades, base products and sugar.
In addition to OFS agar and SSL broth, other culture media can be used as an alternative.
Determination of the total air in bottles and cans
Determination of the total air in containers for beer, beer-based beverages and carbonated beverages
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].
Determination of the soluble dry matter by means of a refractometer
non-alcoholic beverages, juices
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.
Estimation of the fruit juice content in soft drinks and other non-alcoholic beverages using the calculation developed by the Society of German Chemists (GDCh)
This method is suitable for soft drinks and other non-alcoholic beverages.
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.