Detection of indirect beer-spoilage organisms to monitor the microbiological situation in the cold wort area.
Pitching wort
A number of different bacteria that can be found in water, also develop in hopped wort. They are summarised under the term "wort bacteria" and largely belong to the Enterobacteriaceae family. Pseudomonas spp. are occasionally found in water treatment plants. Many microorganisms can only exist or multiply in a sufficiently oxygen-rich atmosphere, i.e. under aerobic conditions.
Preliminary microscopic analysis for aerobic wort bacteria and check for wort bacteria odour after prior aerobic incubation.
To determine whether the wort contains microorganisms capable of reproduction, incubate the wort sample for up to 7 days at 27 ± 2 °C and then analyse using dark-field microscopy.
Determination of the amine content in wort and beer
This method is suitable for wort and beer.
Determination by means of reversed phase chromatography after pre-column derivatization with dansyl chloride and fluorescence and UV detection.
Wort samples of all kinds.
Analysis of wort for beer-spoilage bacteria (anaerobic). In the case of trace infections, it may be necessary to carry out a second enrichment. Slow-growing (e.g. Pediococcus spp.) or thermally damaged microorganisms can also be detected here.
This method describes how to mill grain or malt to produce fine or coarse grist.
Malt intended for use in beer brewing or elsewhere in the food industry
Malt is ground between two horizontally positioned, grooved discs. The lower disc is driven by an electric motor and rotates at approx. 1500 rpm; the upper disc is fixed and therefore does not move. During the milling process, the malt migrates from the center of the discs to the outer edge, where the grist falls through an outlet spout into a grist beaker.
The gap between the discs can be adjusted by turning a socket head screw on a calibrated ring bearing scale markings. The scale on the calibrated ring ranges from 0 to 20, with each scale division corresponding to a gap between the discs of 0.10 mm. Each scale division is subdivided into five smaller divisions; each of the smaller marks is equivalent to 0.02 mm. Two gap adjusting rings ensure reproducible mill settings.
Malt intended for use in beer brewing or elsewhere in the food industry
Viscometric Determination of Gelatinization Temperature (GT)
The gelatinization temperature (GT) can be determined using a rotary viscometer (e.g., amylograph or viscograph, Brabender GmbH & Co. KG, Germany [7] or Rapid-Visco-Analyser (RVA), Perten Instruments, a PerkinElmer Company, USA [8]).
Unlike the analysis method for adjuncts which do not contain a large amount of enzymes, for the analysis of barley malt, a mash with a mash to sparge ratio of 1 : 4 (similar to that commonly found in the brewing process) is used [9]. The sample is heated according to a programmable temperature/time program (refer to table 1) and the viscosity is measured using measuring stirrer throughout the process.
A gelatinization begins to occur, an increase in viscosity is registered; temperature of the sample is measured and identified as the corresponding gelatinization temperature. An increase in viscosity of a minimum of 24 cP (mPa × s) within six seconds is the evaluation criterion for the pasting temperature.
Membrane filtration is a simple way of concentrating microorganisms from a liquid sample.
Filtered beers
Membrane filtration and anaerobic incubation