Malting barley methods used to measure quality

List of western Canadian malting barley methods and tests

α-Amylase activity

α-Amylase activity was determined according to American Society of Brewing Chemists (ASBC) method MALT 7B by segmented flow analysis, using ASBC dextrinized starch as the substrate, and calibrated with standards that have been determined by method ASBC Malt 7A.

Arabinoxylan

Total arabinoxylan content in grain was determined after acid hydrolysis by gas-chromatographic (GC) analysis of alditol acetates using a flame ionization detector.

Ash

Ash content in barley was determined following the American Association for Clinical Chemists (AACC) International Method 08.01.01 by incinerating the ground barley sample in a muffle furnace at 590ºC. Ash content is reported as a percentage on dry matter basis.

Assortment

All samples are passed through a Carter Dockage Tester equipped with a No. 6 riddle to remove foreign material and two slotted sieves to sort the barley. Plump barley is the material retained on a 6/64” (2.38 mm) x 3/4” slotted sieve.

Intermediate Grade is barley that passes through the 6/64” x 3/4” sieve but is retained on a 5/64” (1.98 mm) x 3/4” slotted sieve.

β-Glucan content in wort

β-Glucan content was determined in malt extract by segmented flow analysis using Calcofluor staining of soluble, high molecular weight ß-glucan (ASBC Wort-18B).

β-Glucan content in grain

β-Glucan content was determined in ground barley according to the Megazyme Streamlined Method – assay procedure for determination of mixed linkage β – glucan content in oat and barley flour (Association of Official Analytical Chemists (AOAC) Method 995.16, AACC International Method 32-23, International Association for Cereal Chemistry (ICC) Standard Method No 168)

Diastatic power

Diastatic power was determined by segmented flow analysis, using an automated neocuproin assay for reducing sugars, which is calibrated using malt standards analysed following the official ferricyanide reducing sugar method, (ASBC Malt 6A).

Dietary Fiber

Dietary fiber content in grain was determined by quantitative recovery of insoluble dietary fiber (IDF) and soluble dietary fiber (SDF) fractions in ground barley using an ANKOMTDF Dietary Fiber Analyzer (AOAC Method 991.43). Results were corrected for protein and ash content and reported on a dry matter basis.

Fine-grind and coarse-grind extracts

Extracts were prepared using an Industrial Equipment Corporation (IEC) mash bath and the Congress mashing procedure from 45°C to 70°C. Specific gravities are determined at 20°C with an Anton Paar DMA 5000M digital density meter (ASBC Malt-4).

Free Amino Nitrogen (FAN)

Free amino nitrogen (FAN) was determined in the fine extract according to the official ASBC method Wort-12 by segmented flow analysis.

Germination energy

Germination energy is determined by placing 100 kernels of barley on two layers of Whatman No.1 filter paper, in a 9.0 cm diameter petri dish, and adding 4.0 ml of purified water. Samples are controlled at 20 degrees Celcius and 90% relative humidity in a germination chamber. Germinated kernels are removed after 24 and 48 hours and a final count is made at 72 hours (ASBC Barley 3C).

Kolbach index (Ratio S/T)

Kolbach index was calculated from the formula: (% Soluble protein/% Malt protein) x 100.

Micromalting

Malts are prepared using an Automated Phoenix Micromalting System designed to handle twenty-four 500 g samples of barley or forty-eight 250 g samples of barley per batch.

Malt mills

Fine-grind malt is prepared with a Buhler-Miag disc mill set to fine-grind. Coarse-grind malt is prepared with the same mill set to coarse-grind. The settings for fine- and coarse-grinds are calibrated quarterly, based on the screening of a ground ASBC standard check malt (ASBC Malt-4).

Moisture content of barley

Moisture content of barley was predicted using Near-Infrared Reflectance (NIR) equipment that has been calibrated by the standard ASBC method (ASBC Barley 5C). Moisture content in grain was also determined by drying the ground barley in the oven for 65 min. at 130ºC (AACC International Method 44-15.02, onestage, air-oven).

Moisture content of malt

Moisture content of malt was determined on a ground sample by oven drying at 104°C for 3 hours (ASBC Malt-3).

Protein content (N x 6.25)

Protein content is predicted on dockage free barley using NIR equipment that has been calibrated by Combustion Nitrogen Analysis (CNA). Malt protein was measured by CAN using a LECO Model FP-628 CNA analyzer calibrated by ethylenediamine tetraacetic acid (EDTA). Samples are ground on a UDY Cyclone Sample Mill fitted with a 1.0-mm screen. A moisture analysis is also performed and results are reported on a dry matter basis (ASBC Barley 7C).

Rapid Viscometric Analysis

The degree of pre-germination in barley was determined as described by Izydorczyk (2005); see Using RVA to measure pre-germination in barley and predict germination energy after storage. Samples were analyzed using the RVA-4 (Newport Scientific) and the Stirring Number Program. Final viscosity values were presented in Rapid Visco Units (RVU).

Starch

Starch content in grain was determined in ground barley according to the Megazyme Amyloglucosidase / α-Amylase Method – assay procedure for determination of total starch content in cereals and food products not containing resistant starch, D-Glucose and/or maltodextrins (AOAC Method 996.11, AACC International Method 76-13.01).

Viscosity

Viscosity was measured on fine grind Congress wort using an Anton Paar Lovis 2000 automated rolling ball viscometer (ASBC Wort-13B).

Vitamin E

The content of tocopherols and tocotrienols in barley was determined by reverse phase high performance liquid chromatography (RP-HPLC) using a fluorescent detector. Tocols were extracted from barley after saponification with hexane:ethyl acetate (8:2, volume / volume).

Water Sensitivity

Water sensitivity was determined exactly as described for germination energy, except that 8.0 ml of purified water is added to each petri dish (ASBC 3C, IOB and EBC procedure). The water sensitivity value is the numerical difference between the 4ml and 8ml tests.

Weight per Thousand Kernels

A 500 gram sample of dockage-free barley is divided several times in a mechanical divider to obtain one representative sub-sample weighing 40 g. All foreign material and broken kernels are removed from one 40 g portion and the net weight determined. The number of kernels was then counted with a mechanical counter and thousand kernel weight was calculated (as is basis) (Institute of Brewing’s Recommended Methods of Analysis, Barley 1.3 (1997)).

Wort-Soluble Protein

Wort-soluble protein was determined spectrophotometrically using ASBC method Wort-17.

Wort colour

Wort color was determined spectrophotometrically using ASBC method Wort-9 and Beer-10.