MALTING, BREWING AND DISTILLING 223 pressure through the bed of grains. a plenum compounds is favoured by the combination of high below the floor is provided as in the earlier stages temperatures with wet malts (Briggs, 1978). Small of the malting process. A recent innovation in contributions to malt colour may be caramelized kiln design is the double-deck version. In this sugars and oxidized polyphenols and other system green malt is loaded on to the upper deck contributions come from aldehydes, ketones, and transferred to the lower deck after partial alcohols, amines and miscellaneous other sub drying. Warmed air is passed first through the stances including sulphur-containing compounds drier, lower bed before passing, unsaturated, to and nitrogenous bases. These are discussed in the upper bed where it is capable of removing detail by briggs(1978)and Palmer(1989). Peated moisture from the green malt distillery malts, for Scotch whisky manufacture The depth of green malt in a modern kiln is take up many substances from the peat smoke 0.. 2 m. For maximum efficiency the bed and contain various alkanes, alkenes, aldehydes should be level and uniformly compacted, a alcohols, esters, fatty acids, aromatic and phenolic condition readily achieved by the automatic or substances, including phenol and cresols the use semi-automatic loading machinery available today. of peat as a fuel for kilning originated in cottage Conditions for kilning are determined by the industry enterprises in the crofts of the Scottish ature of the end product required. Variables Highlands where peat was the only available fuel include the extract potential, moisture content, for domestic heating In lowland distilleries peat colour and enzyme activity. Curing temperatures heating has now been superseded by a succession range from 80 to 100C. In modern kilns the of fuels, currently oil or gas. Direct heating by maltster is assisted in monitoring and controlling these fuels is not permitted as they can lead to conditions by control programmes incorporated introduction of nitrosamines into the product into automated systems Peatiness is a valued character of malt whiskies Enzymes survive high curing temperatures however and direct heating with peat is the rule best if the malt is relatively dry, but under these in their production conditions colour and flavour development are For production of brewing malts a major minimal. They develop mainly as a result of economic consideration is brewer's extract. This Maillard reactions occurring between the reducing is measured as hot water extract available as the roups of sugars and amino groups, mainly of soluble nitrogen required to maintain fermenta amino acids. Development of additional flavour tion and beer quality properties. An analysis of Table 9.1 Analytical Characteristics of Barley and Ale Malt Moisture content %o oluble nitrogen o nitrogen Minerals %o approx 2 olour EBC under 1.5 Hot water extract(1/kg) Dextrinizing unit(alpha-amylase) Endo B-glucanase(IRV units) under 100 of aberdeen unitMALTING, BREWING AND DISTILLING 223 pressure through the bed of grains. A plenum compounds is favoured by the combination of high below the floor is provided as in the earlier stages temperatures with wet malts (Briggs, 1978). Small of the malting process. A recent innovation in contributions to malt colour may be caramelized kiln design is the double-deck version. In this sugars and oxidized polyphenols and other system green malt is loaded on to the upper deck contributions come from aldehydes, ketones, and transferred to the lower deck after partial alcohols, amines and miscellaneous other sub￾drying. Warmed air is passed first through the stances including sulphur-containing compounds drier, lower bed before passing, unsaturated, to and nitrogenous bases. These are discussed in the upper bed where it is capable of removing detail by Briggs (1978) and Palmer (1989). Peated moisture from the green malt. distillery malts, for Scotch whisky manufacture, The depth of green malt in a modern kiln is take up many substances from the peat smoke 0.85-1.2 m. For maximum efficiency the bed and contain various alkanes, alkenes, aldehydes, should be level and uniformly compacted, a alcohols, esters, fatty acids, aromatic and phenolic condition readily achieved by the automatic or substances, including phenol and cresols. The use semi-automatic loading machinery available today. of peat as a fuel for kilning originated in cottage Conditions for kilning are determined by the industry enterprises in the crofts of the Scottish nature of the end product required. Variables Highlands where peat was the only available fuel include the extract potential, moisture content, for domestic heating. In lowland distilleries peat colour and enzyme activity. Curing temperatures heating has now been superseded by a succession range from 80" to 100°C. In modern kilns the of fuels, currently oil or gas. Direct heating by maltster is assisted in monitoring and controlling these fuels is not permitted as they can lead to conditions by control programmes incorporated introduction of nitrosamines into the product. into automated systems. Peatiness is a valued character of malt whiskies Enzymes survive high curing temperatures however and direct heating with peat is the rule best if the malt is relatively dry, but under these in their production. conditions colour and flavour development are For production of brewing malts a major minimal. They develop mainly as a result of economic consideration is brewer's extract. This Maillard reactions occurring between the reducing is measured as hot water extract available as the groups of sugars and amino groups, mainly of soluble nitrogen required to maintain fermenta￾amino acids. Development of additional flavour tion and beer quality properties. An analysis of TABLE 9.1 Analytical Characteristics of Barley and Ale Malt Constituent Barley Ale malt Moisture content YO 15 4 Starch YO 65 60 0-D-glucan YO 3.5 0.5 Pentosans % 9.0 10.0 Lipid YO 3.5 3.1 Total nitrogen % 1.6 1.5 Total soluble nitrogen Oh 0.3 0.7 a-Amino nitrogen Oh 0.05 0.17 Sucrose o/o 1.0 2.0 Minerals Oh approx 2 approx 2 Colour "EBC under 1.5 5.0 Hot water extract (1"ikg) 150 305 Diastatic power (beta-amylase "L) 20 65 Dextrinizing unit (alpha-amylase) under 5 30 Endo P-glucanase (IRV units) under 100 500 Source: Palmer, 1989. Reproduced by courtesy of Aberdeen University Press