Determination of the viscosity of beverages using a micro-viscometer.
Wort, Beer, Mixed beer beverages, Non-alcoholic soft drinks, Juices, Beverages in general
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.
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.
The sample is heated directly on the weighing pan in the drying chamber using microwaves. The water evaporates and is removed by a compressor. In order to avoid disturbing the weighing process as little as possible, the sample is protected from the flow of gas by a porous cover. The change in weight is measured directly; after a constant weight is reached, it is evaluated.
With microwave-vacuum drying, the vaporization temperature is lowered, resulting in a more gentle drying process. Additionally, the samples are under constant rotation to prevent degradation and burning of the sample.
Prediction of the extract content and predetermination of the processability and value of a lot of barley for brewing purposes
The behavior of barley during the malting process, which is intended for large-scale malt production, must be known.
MEBAK approved and adopted a micromalting procedure on 6 April 1971 as a standard method for predicting the extract content and for determining the suitability of barley varieties for malting. In 2003, MEBAK shortened the procedure by one day for a total of six days for vegetative growth (steeping and germination), the same length of time as the EBC procedure.
The method describes how to determine the viscosity using a micro viscometer (e. g. Lovis).
Suitable for all worts and types of mash.
The measuring principle of the Lovis micro viscometer is based on the Höppler “Falling Ball Viscometer”. A ball of known dimension rolls through a closed capillary, which is inclined at a defined angle. Inductive sensors detect the ball along an exactly defined distance of approximately 100 mm or 25 mm. The rolling time is measured by the instrument and is used for dynamic viscosity calculation. The temperature is precisely regulated by thermoelectric Peltier elements and checked by a Pt-100 temperature sensor. A temperature accuracy of ±0.02 °C and repeatability of ±0.005 °C can be reached.
Suitable for any wort or mash
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.
Definition:
1 square meter per second is the kinematic viscosity 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