Malt intended for use in beer brewing or elsewhere in the food industry
After boiling for two hours on a reflux condenser, the wort is clarified using membrane filtration. The color is measured with a spectrophotometer.
Applicable for all (laboratory) worts
The Congress wort is heated in order to inactivate the amylolytic enzymes. Afterwards, 16 g/100 ml yeast is added, and the wort is allowed to completely ferment out in approx. 7 h.
Determination of 3-hydroxy-2-butanone (acetoin) in beer.
The method is suitable for beers of brewed to any original gravity or of any alcohol content.
The compound 3-hydroxy-2-butanone (acetoin) is derived from diacetyl and is created through the reductive activity of yeast. One further reaction mechanism for the formation of 3-hydroxy-2-butanone is condensation of both free and activated (bound to thiamine pyrophosphate [TPP]) acetaldehyde.
3-Hydroxybutanone is oxidized to 2,3-butanedione (diacetyl) by iron chloride in the presence of iron sulfate and determined using gas chromatography and the headspace analysis method.
Determination of the viscosity of beverages
wort, beer, beer-based beverages, NAB, juice, beverages in general
Capillary viscometers measure the kinematic viscosity of Newtonian fluids, unlike falling ball and the rotational viscometers, which directly measure the dynamic viscosity. However, with values for the kinematic viscosity and the density of the test liquid, the dynamic viscosity can be calculated.
The time required for a volumetrically defined amount of fluid (the volume between two marks on the tube of the viscometer) to flow through a capillary of a defined length is measured.
1 square meter per second of a homogenous fluid with a dynamic viscosity of 1 Pa × s and a density 1 kg/m³
The unit for expressing kinematic viscosity (the relationship of viscosity to density = viscoplasticity) is 1 m²/s = 106 mm²/s
The kinematic viscosity is expressed as 1 square meter per second of a homogenous fluid with a dynamic viscosity of 1 Pa × s and a density 1 kg/m³.
Determination of the amount of cold break material in the pitching wort
Cast-out wort, wort from the midpoint of chilling/pitching wort (without yeast)
The hot break material (trub) and any hop particles which may be present in the wort, must first be removed. After the wort has been cooled to 2 °C, it is filtered through a glass fiber filter. The residue remaining on the filter is dried and then weighed.
Cold break material or cold trub refers to all material that settles out in the process of chilling wort after separation of the hot trub or hot break material. Cold trub can be filtered out of the wort and primarily consists of proteins (48–57 %), tannins (11–26 %) and carbohydrates (20–36 %). The amount of cold break material in wort depends on the quality and composition of the raw materials, brewhouse equipment and wort handling. In academic and professional circles, opinions regarding the significance of cold break material for downstream processes and for the quality of the finished beer are strongly divided [1, 2, 5]. Under certain circumstances, the quantity of cold break material in wort may exceed 250 mg/l, especially where accelerated fermentation is practiced. Ultimately, this can detract from the flavor of the finished beer [3]. Breweries, where removal of the cold break material has been practiced successfully, determine the quantity of cold break in their pitching wort at regular intervals, in order to evaluate the efficacy of their separation equipment.
This method describes how to determine the fermentable carbohydrates in wort or in the Congress wort using high performance liquid chromatography.
Applicable for all (laboratory) worts
Fructose, glucose as well as disaccharides and trisaccharides (maltose and maltotriose) are determined using high performance liquid chromatography (HPLC).
Wort or beer is deionized using an ion exchanger. The sample is filtered and concentrated using a solid-phase column and analyzed chromatographically. The concentration of the sugars present in the sample is calculated from the chromatograms obtained by analysis of the calibration solutions.