Understanding Malt Analysiss
Malt analysis provides guidance on the effectiveness of the malting process and the suitability of the malt for brewing. The brewer judges malt quality by referring to the malt analysis provided by the maltster. Maltsters generally publish “typical” malt analyses, which are provided before purchase, and a lot analysis of the malt, which is provided at the time of purchase. Malt is analyzed in accordance with standard industry tests such as American Society of Brewing Chemists (ASBC) or the European Brewing Convention (EBC) standard mashes for easier comparison. A malt analysis provides very useful information, listing a number of parameters. A malt analysis will typically list three types of data—physical analysis of the kernel, wort analysis, and chemical analysis (Figure 2.13). While each attribute uniquely impacts the brewing process or finished beer, some have a greater impact and significance than others.
Assortment refers to the size distribution of the grain or malt kernels, as measured by standard screens. It is sometimes described in other terms depending on the maltster, such as “plump” or “sieving.” The higher the percentage, the larger the kernel size.
Bushel weight indicates the size and density of malt, and can be used to calculate how much malt will fit in a silo or other storage unit.
Friability, expressed as a percent, refers to the softness of the kernel and is determined by the amount of malt that passes through a rotating screen. Friability is greatly influenced by overall malt modification, malt protein, and malt moisture.
Mealiness is a classification system used to indicate the level of malting. Often mealiness is expressed as “mealy,” “half-glassy,” or “glassy” (steely of vitreous). Mealy kernels are those in which the endosperm is not more than 25 percent glassy..
Moisture content (MC) is shown as a percentage of the total malt weight; the higher the MC content, the less extract yield per kilogram. The moisture content can be expressed as “extract dry” or “extract as is”—which includes the moisture content. The brewer needs to take into account the moisture content of each lot analysis in calculating the weight of malt required since the moisture content influences the amount of extract yield.
During kilning, chemical reactions take place, producing color compounds. The higher the kilning temperature, the more color compounds produced. American maltsters quote color in Standard Reference Method (SRM) units or degrees Lovibond, an older method. Degree Lovibond is an older method of visual measurement and is used because of old habits. Standard Reference Method is a more sophisticated method, involving the use of light meter analyzers to assign a number to light intensity.
Extract is the amount of soluble material released by the malt in a laboratory test mash. Malt extract values are used along with brewhouse efficiency to estimate the original gravity of wort mashed from a specified grain bill. Extract may be expressed as percent extract fine-ground dry basis (FGDB) or as percent extract coarse-ground dry basis (CGDB). Extract is reported on an “as-is” and “dry basis”. As-is extract is more relevant to a brewer’s formulation than dry basis because it is a more practical way of representing yield potentials.
Viscosity (cP) is a measure of the “thickness” of the wort solution. It is expressed in centipoise units (cP), a measure of the breakdown of beta-glucans.
Turbidity (haze) is caused by proteins and beta glucans that have not been sufficiently degraded, this attribute has relatively little impact on the brewing process but can contribute haze to the finished beer.
Beta-glucan content is important because it can increase viscosity of the wort, which leads to slower runoffs during lautering and results in beer filtration problems. In addition, it can cause problems and may contribute to chill haze. pe malts in a roaster use the term “crystal” to designate them as roaster produced.
Protein measured in malt is called total protein. Protein measured in wort prepared in a laboratory mash is called soluble protein. The ratio of soluble to total protein is called the S/T ratio, or the Kolbach index. Because protein is the principal source of nitrogen, protein is often estimated from the nitrogen content: % protein = % nitrogen x 6.25.
Dimethyl sulfide (DMS) usually provides a good indication of the intensity of a beer’s malty/sulfury taste. The precursor compound to DMS, called S-methylmethionine (SMM), is produced during the germination of barley, a key step in malting.
Diastatic enzymes are necessary in brewing to convert starches into simple sugars that yeast can ferment. Conversion of starch to reducing sugars by the diastatic enzymes in malt is due to the action of two enzymes, alpha-amylase and beta amylase. Alpha-amylase levels will indicate the ability of malt to convert a standard mash properly.
The enzymatic power of the malt enzymes that break-down complex carbohydrates into sugars is measured as DP (diastatic power in degrees Lintner). The principal enzymes in breaking down starch are alpha-amylase and beta-amylase. The higher the number of degrees Lintner, the greater the diastatic power of the malt. High enzyme activity is often associated with well-modified barley malts. Malts with high diastatic power will convert faster in the mash and are capable of converting a greater quantity of adjuncts too.
Click on the following topics for more information on barley malts.