Determination of the aromatic alcohols guaiacol, tryptophol, 4-ethyl guaiacol, 4-vinyl guaiacol, eugenol, tyrosol, 4-ethylphenol, 2-phenylethanol in beer
The method is suitable for beer brewed to any original gravity or to any alcohol content.
The aromatic alcohols in beer are isolated using solid-phase extraction and are detected using gas chromatography-mass spectrometry.
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.
Barley intended for the production of malt is to be evaluated on the basis of the characteristics described below.
visual assessment
This method describes how to determine whether kernels are cracked as part of the visual and manual inspection of a lot of barley.
Barley intended for the production of malt is to be evaluated on the basis of the characteristics described below.
Visual assessment
This method describes how to determine whether a lot of grain is contaminated with ergot visually through manual inspection.
Barley intended for the production of malt; therefore, the kernels are to be evaluated on the basis of the characteristics described below.
A representative sample of grain is visually inspected for the presence of ergot sclerotia.
This method evaluates the varietal purity of a lot of barley by means of the HCl test.
Barley intended for the production of malt is to be evaluated on the basis of the characteristics described below.
This test detects the presence of most varieties of two-rowed and multi-rowed winter barley possessing a green aleurone layer. This test is based upon the reaction between HCl and the green pigment, which turns red in its presence.