This method describes how to determine development of the acrospire in malt kernels. The method provides an overview of the uniformity of germination.
Malt intended for use in beer brewing or elsewhere in the food industry.
Visual method
Determination of the amount of cold break material in the pitching wort
Cast-out wort, wort from the midpoint of chilling/pitching wort (without yeast)
The hot break material (trub) and any hop particles which may be present in the wort, must first be removed. After the wort has been cooled to 2 °C, it is filtered through a glass fiber filter. The residue remaining on the filter is dried and then weighed.
Cold break material or cold trub refers to all material that settles out in the process of chilling wort after separation of the hot trub or hot break material. Cold trub can be filtered out of the wort and primarily consists of proteins (48–57 %), tannins (11–26 %) and carbohydrates (20–36 %). The amount of cold break material in wort depends on the quality and composition of the raw materials, brewhouse equipment and wort handling. In academic and professional circles, opinions regarding the significance of cold break material for downstream processes and for the quality of the finished beer are strongly divided [1, 2, 5]. Under certain circumstances, the quantity of cold break material in wort may exceed 250 mg/l, especially where accelerated fermentation is practiced. Ultimately, this can detract from the flavor of the finished beer [3]. Breweries, where removal of the cold break material has been practiced successfully, determine the quantity of cold break in their pitching wort at regular intervals, in order to evaluate the efficacy of their separation equipment.
Barley intended for the production of malt is evaluated with regard to pre-germination.
Visible pre-germination is evident at the rootlet and is therefore grounds for rejecting a barley lot. However, after the barley is cleaned and the rootlets are removed, the so-called “hidden pre-germination” can be made visible using the staining methods described below.
Kernels suspected of having pre-germinated are boiled for ½−1 min in a 20 % solution of copper sulfate, allowed to remain for 30 min in the hot solution and are subsequently rinsed with water. The acrospire is stained green, making it clearly visible.
Barley intended for the production of malt is evaluated with regard to pre-germination.
Kernels suspected of having pre-germinated are boiled in water and then allowed to remain in cold water for some time. Thereby, the husks become transparent, making the embryo and the acrospire, if present, visible.
This method describes how to determine the organic acids in wort and the Congress wort using a cation exchanger.
Applicable for all (laboratory) worts
A cation exchanger based upon a sulfonated, crosslinked styrene/divinylbenzene copolymer is used to determine various organic acids in wort. Due to the high ligand density, the separation mechanism is based upon a combination of ion exclusion, ligand exclusion and steric exclusion; detection is performed using a UV detector.
This method describes the determination of sodium in wort or Congress wort by means of atomic absorption spectrometry.
Suitable for analysis of all (laboratory) wort samples.
Sodium in wort is measured using the AAS technique by directly aspirating the diluted sample into an acetylene oxygen flame; the measurement is made at 589 nm.