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
This method describes how the extract content of adjuncts is determined.
After gelatinization of the starch in the adjunct, the starch is liquefied and converted through the addition of malt. Subsequently, the extract content is determined according to the procedure given in the method for malt analysis.
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.
The nitrogen/raw protein content of barley intended for the production of brewing malt must be determined in advance.
The sample is combusted in a pure oxygen atmosphere at approx. 1000 °C. The resulting mix of gases comes into contact with a CuO/Pt catalyst and is thereby completely oxidized and subsequently freed of all by-products which could potentially interfere with analysis.
After the nitrogen oxides formed in the combustion process are reduced upon contact with tungsten, all nitrogen compounds in the sample are reduced to elemental nitrogen (N2). The elemental nitrogen is then detected by means of a thermal conductivity detector (TCD), the signal of which is quantitatively evaluated by a dedicated integrator.
This method describes how to determine the extract content of liquid adjuncts by means of relative density measurement.
Adjuncts in liquid form which are soluble in water
Determination of relative density sL 20/20 °C with a pycnometer or other suitable density measurement device