Valid for all non-turbid beers
By incrementally adding increasing amounts of a saturated ammonium sulfate solution to beer, haze appears as a result of protein precipitation. The amount of the ammonium sulfate solution necessary to produce haze is directly proportional to the stability of the beer. The ammonium sulfate precipitation value expresses the ml of saturated ammonium sulfate solution that must be added to 100 ml of beer in order to produce a barely perceptible opalescence.
This method describes how to determine the clarity or turbidity of water using a turbidimeter.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
A water sample containing undissolved substances diminishes the incident light radiation and scatters it unevenly in all directions. The intensity of the scattered radiation depends on the wavelength of the incident light, on the measurement angle and on the form and size of the suspended particles. The results of the turbidimetric analysis are related to a “standard formazin turbidity”.
A defined amount of formaldehyde is added to beer. Haze forms in the beer which is correlated with "warm days".
Valid for all non-turbid beers
The formation of haze is forced through the addition of formaldehyde and storage at 0 °C. The difference in the turbidity formed and the turbidity at the beginning is compared.
Determination of the proportional composition of grist fractions through sieve analysis
Malt grist, grist from adjuncts
The extract yield in the brewhouse is highly dependent on optimal milling of the malt or other grain. The composition of the brewery grist should therefore be monitored on a regular basis.
The sieve analysis is performed on a sample of brewery grist of a known weight with a shaking device containing a set of sieves (according to DIN ISO 3310-1 specifications or a Pfungstädter plansifter sieving device).
The sample is extracted with petroleum ether in a Soxhlet apparatus equipped with a reflux condenser; the solvent is evaporated and the crude fat residue weighed.
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.