Kiln-dried malt

Coloured malt is produced by roasting of kiln-dried malt without prior saccharification at a temperature of 190-220°C. It is used to increase the colour of dark beers. The ground malt is dispersed in water, a process which also causes a hydrolysis of starch and other malt components through the malt enzymes. By means of filtration, these flavours are gained in a fermentable, clear solution which is then cooked for the flavourisation with hop. 

Scanlan and coworkers have extensively investigated the formation of NDMA. in malt. They have demonstrated that the plant alkaloids hordenine and gramine are effective precursors of NDMA in model systems and that it is likely that NVNA may also be present in direct fired kiln dried malt (Mangino et al. 1981). 

The cereals are soaked (steeped) in water and then allowed to germinate. The product, green malt, is dried and mildly roasted into a more or less dark and aroma-rich kiln-dried malt. During processing, the rootlets are removed from the malt. The loss due to malting is 11-13% of the dry weight. Prior to use, the malt is stored for 4—6 weeks. 

In double-deck kilns, green malt is dried on the upper deck to 10—20% moisture with influent air temperature of 40—60°C during the first half of the... 

Only two companies produce specialty malts in roasters or specialty kilns in North America Breiss Malting Co. (Chilton, Wisconsin) and Extractos y Maltas (Mexico City). Other malting companies produce high dried malts in conventional kilns which are used by brewers for color or flavor purposes. Specialty malts represent less than 2% of malt sold in North America. 

Darre,/. drying, kiln-drying drying room or kiln Brewing) malt kiln Metal.) liquation hearth withering. 

The length of time which is allowed for germination depends upon the use for which the malt is required. For distilling and vinegar making the usual time is 20 days, while the kiln drying occupies 3 or 4 days. 

Made from barley malt and having a smoky taste, obtained by using peat instead of coal as fuel in the kiln drying of the malt. Changes in the variety of peat used materially affect the flavor. This includes scotch whiskeys commonly classified in the British Isles as follows (1) Highland malts, (2) Lowland malts, (3) Campbell towns, (4) Islays. 

The principles involved in hop drying are similar to those involved in barley drying and the kilning of malt (see Vol. I, Chapter 6). 

In addition to the use of nitrite and nitrate as additives, a second general mechanism by which foods may become contaminated with NA is through the drying of foods in air which has been directly heated in an open flame. The highest levels of VNA resulting from this common method of food processing have been in the kilning of malted barley. Concentrations of NDMA in the dried malt of over 100 yg/kg have been reported (Hotchkiss et al. 1980 Preussmann et al. 1981). 

Whiskey, depending on the kind, is made by different processes. The raw material for Scotch single malt whiskey is barley malt which has been exposed to peat moss or coal smoke during kiln drying. Such smoked malt is mashed at 60 °C and filtered. The resulting wort is then fermented at 20-32 °C after the addition of yeast (Saccha-romyces cerevisiae). Irish whiskey is never made from smoked malt. The distillation is conducted in two steps, sometimes in simple pot stills. The harsh, raw liquor is collected in the first distillation step. The undesirable harsh components are removed in the head and tail fractions in the second distillation. 

To reduce drying time, maximum airflows are used during the first portion of the kilning cycle until the exit air is no longer saturated with moisture. Airflow then is reduced or recirculated to conserve energy. Average fuel consumption for a United States kiln is ca 5.9 x 10 kJ/t (1.4 x 10 kcal/t) ) malt, with a range of 2.9-10 X 10 kJ/t of malt. 

A wide variety of special malts are produced which impart different flavor characteristics to beers. These malts are made from green (malt that has not been dried) or finished malts by roasting at elevated temperatures or by adjusting temperature profiles during kilning. A partial Hst of specialty malts includes standard malts, ie, standard brewers, lager, ale, Vienna, and wheat caramelized malts, ie, Munich, caramel, and dextrine and roasted products, ie, amber, chocolate, black, and roasted barley. 

It has been shown in these studies that the principal, and probably only significant source of NDMA, is malt which had been dried by direct-fired drying (21, 73). It is well known that malts kilned by indirect firing have either low or non-detectable levels of NDMA (74). Consequently, changes in malting procedures have been implemented in both the U.S. and Canada which have resulted in marked reductions in N-nitrosamine levels in both malts and beer (70,74). For example, sulfur dioxide or products of sulfur combustion are now used routinely by all maltsters in the U.S. to minimize N-nitrosamine formation (70). The Canadian malting industry, on the other hand, has... 

Malt is produced by steeping barley in water for several days. This initiates germination, which activates several enzymes important in the digestive process that occurs in malt. The germinated barley is then dried and kilned at about 80°C, or higher for darker malts. 

---