MALTING QUALITY TRAITS - Canadian Malting Barley Technical ...

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24 Chapter Four (2) The Curing Stage The curing stage begins after the “drying front” (moisture removal from the green malt bed takes place in layers, the lower layers dry first, the basal drying zone progressively moving upward), reaches the surface of the grain bed, which is accompanied by the so-called ‘breakthrough’ (a point of time when the drying zone reaches the upper surface of the grain bed). Therefore this stage is sometimes referred to as the “post-break”. During this part of the cycle, the moisture content of the malt is further reduced to its final level of approximately 4% from the 10-12 % achieved in the free drying stage. In contrast to the drying stage, this stage is a much slower drying process since the rate of water removed from the barley is much slower, requiring more time. During this stage, the air-on temperature may be increased to 65-75°C with a progressive air volume reduction and increment of air recirculation. In the final part of the curing stage, the air-on temperature may be increased to 80-85°C for 3-4 hrs for production of pale malt, and up to 100°C for production of ale malt. The complex chemical reactions between the products of starch degradation and protein degradation (i.e. sugars and amino acids) at high temperature produce the typical colors, flavors and aromas associated with malts. Enzyme actions are largely halted and some enzymes have been destroyed, although the final malt still contains adequate levels of enzymes for successful brewhouse performance. After kilning, the malt must be cooled to room temperature (preferably to 20°C or less) to avoid further color formation and enzyme destruction. Usually this is accomplished by cooling the malt below 37°C, and then cleaning it to remove rootlets, sprouts and loose husks. The finished cleaned malt is then transferred to storage silos that are arranged according to variety and quality specifications. After a target aging period, malt with similar quality from the silos are blended to meet the precise specifications required by the brewers, then go through a final cleaning prior to loading into a truck or railcar for shipping. In theory, from the same batch of “green malt” unlimited types of malt could be produced by kilning the green malts under different conditions. This further emphasizes the importance of the kilning stage for quality malt production. Processing Canadian malting barley varieties The key malting stages of malt have already been outlined in this section. The discussion here will focus on how to malt Canadian barley and to fully utilize its quality potential. The scope of these discussions will be limited to producing pale malt, because the greatest amount of malt produced in North America and in other parts of the world is pale malt.
Fig. 1 A tower malting plant at Alix, Alberta, Canada. 1 2 3 4 5 6 7 25 Barley Supply Elevator Malt Cleaning/Loading Barley Cleaning/Grading Barley Surge Bins Barley and Malt Storage Malt Surge Bins Kilns 4 Chapter Four 2 3 For practical consideration, the choice of malting cycles (programs) are determined by factors such as barley variety, quality of the barley, achievable malt quality, process condition requirements and the malting facility. Among these factors, barley variety, barley quality and its malting behavior, are perhaps the most influential considerations and need to be the first concerns in designing a commercial malting program. It has been well recognized by the malting and brewing industry world wide, that the current Canadian malting varieties have some unique quality attributes in comparison with malting barley of other origins including: • Low degree of dormancy • Uniform kernel size and relatively thin husks • Good germination energy and germination vigor • Barley protein content on average may be higher than European and Australian malting barley • High extract yield • High levels of enzymes • Adequate levels of FAN • Easy to malt and to produce malt with consistent quality under different malting conditions • Highly fermentable wort, ideal for high adjunct levels 5 6 7 Schematic of a typical Canadian malthouse 7 1 9 8 8 9 Kiln Air Supply Buildings Steep Tanks Pre-Germination box Turner Germination boxes Water supply Boiler House 25
Page 1 and 2: Canadian Barley Malting and Brewing
Page 3 and 4: Copyright © CMBTC 2012 Design and
Page 5 and 6: Canadian Malting Barley Production
Page 7 and 8: Figure 2: Percentage of Barley Area
Page 9 and 10: Malt Production for Domestic and Ex
Page 11 and 12: 2 IN Malting Barley Selection, Hand
Page 13 and 14: To better understand visual evaluat
Page 15 and 16: Barley Moisture Content Barley mois
Page 17 and 18: 3 IN Figure 1. Cross-section of a b
Page 19 and 20: Figure 3. TOP: Barley endosperm sho
Page 21 and 22: 4 Introduction Malting practices ma
Page 23: levels promote rapid modification,
Page 27 and 28: production, consequently uneven chi
Page 29 and 30: 5 Brewing Whirl Pool Hot Wort Tank
Page 31 and 32: centre timing. A savings of 15 minu
Page 33 and 34: One of the known advantages of usin
Page 35 and 36: Malting Barley Varieties Under Deve
Page 37 and 38: TM COMPARATIVE MALT QUALITY PARAMET
Page 39 and 40: CDC COPELAND Two-rowed, a cross of
Page 41 and 42: CDC POLARSTAR Two-rowed, a cross of
Page 43 and 44: NEWDALE Two-rowed, a cross of CDC S
Page 45 and 46: LEGACY TM Six-rowed, a cross of Exc
Page 47 and 48: TRADITION TM Six-rowed, a cross of
Page 49 and 50: Chapter Seven responsible for barle
Page 51 and 52: Chapter Seven Once selected, all of
Page 53 and 54: 8 THE Chapter Eight Canadian Grain
Page 55 and 56: Chapter Eight Grain Safety The GRL
Page 57 and 58: 9 THIS Chapter Nine Organizations a
Page 59 and 60: Chapter Nine associated government
Page 61 and 62: Contact List Organizations Brewing
Page 63 and 64: Acrospire Glossary of Terms Adjunct
Page 66: 66 Copyright © CMBTC 2012 Printed

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