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.
The gelatinization temperature can be determined using a rotary viscometer (e.g., Amylograph or Viscograph, Brabender GmbH & Co. KG, Germany [4] or a Rapid-Visco-Analyser, RVA, Perten Instruments, a PerkinElmer Company, USA [8]).
A suspension consisting of a finely ground sample and water is produced, whose precise mixing ratio should correspond to the analysis protocol for the adjunct in question. However, since for many cereals and pseudocereals no official analysis protocol exists, the initial weight for the adjuncts listed in table 2 has been determined empirically [3].
Once the suspension is prepared it is attempered according to a pre-programmed temperature/time program, and the viscosity is determined on a continuous basis by means of a rotor and a rotary torque measurement (fig. 1). When gelatinization begins, an increase in the viscosity is registered, and the corresponding sample temperature is defined as the gelatinization temperature. The standard evaluation criterion (PT) is a viscosity increase of at least 24 cP (≙ mPas) within six seconds.
Prior to storage, the moisture content of barley must be determined.
Measurement of the electrical resistance in the ground and pressed sample
Prior to storage, the moisture content of barley must be determined.
The electrical capacitance of a whole, unground grain sample is measured. The apparatus contains three sensors:
Capacitance
The moisture present in a sample absorbs the electrical energy between the walls of the sample container. The electrical signal or the “capacity” increases with higher moisture contents of the sample and with larger sample sizes.
Oscillating weight balance
The oscillating weight balance measures the frequency to determine the mass.
Temperature correction
The capacitance of the sample rises with the temperature. A Thermistor temperature sensor is built into the sample container. The microprocessor automatically corrects for the moisture content.
This method describes how to determine the tendency of a sample to exhibit gushing.
Malted and unmalted grain intended for use in beer brewing or elsewhere in the food industry
A sample is collected of the cereal to be tested and a hot water extraction is carried out. After cold break separation, the sample is carbonated and bottled. After shaking and then opening the bottle, the volume of liquid that fobs over and out of the bottle is measured. This value is used to determine the gushing potential for the malt or adjunct.
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.