Munich malt is high-kilned malt. High-kilned malt is malt that is kilned at a higher temperature. So it undergoes the same production as normal malt but differs in the conditions used for kilning the malt. Munich malt is associated with dark coloured and high flavour ales.
Woonton, B. et al explain that malt is produced by the controlled germination of barley grains which is initiated by steeping barley grains in water, followed by germination and kilning periods.
Briggs, D. 1998, defines the malting process as the limited germination of cereal grains such as barley. The stages of malting are steeping, germination and kilning.
Scannell, A. 2012, defines the objectives of malting to include:
- Initiate germination and embryonic growth
- Production and activation of barley enzymes
- Enzymatic breakdown of proteins and cell wall carbohydrates
Steeping -
Steeping initiates the germination of the barley grain. Mayolle, J. et al state how steeping results in water uptake by the grain, increasing the grain water content up to 43-46%. Water and oxygen are supplied to the interior of the barley kernel, allowing for enzymes to become active and start germination. The rate of water intake influences enzyme formation and growth, also the warmer the water the faster the uptake. Darker malts, such as munich malt have a higher degree of steeping (44-47%) than pale malt (42-44%). The water content of steeped barley is also known as the degree of steeping. Barley is steeped for 36-52 hours to obtain the high degree of steeping found in munich malt. (Scannell, A. 2012)
Germination –
The germination process provides water to the barley ensuring that the moistuer content is maintained above 40% in the grain. Controlling the water content along with controlling the temperature during germination is very important. For the production of darker malts such as Munich malt the temperature is kept between 23-25°C. The duration of germination is 8-11 days for dark malts (Gallagher, E. 2009, p 183). During Germination the barley is agitated or turned to ensure even germination of grains. (Scannell, A. 2012)
Kilning –
The aim of the kilning process is to dry the malt to obtain a longer shelf life and to stop all biochemical reactions that occur during germination. Another aim of kilning drying is the formation of typical malt flavours from the barley. Kilning is a two step drying process consisting of initial drying and kilning process itself. In initail drying the water content of the malt is reduced to about 10% at temperatures of 45-65°C. After 10-12hours, the end of this initial drying is marked by an increasing outlet of air temperature. In the second phase, the drying air is heatd to 80-85°C, this is done to decrease the moisture content of the malt to 3.5-4%. (Gallagher, E. 2009, p 183)
Vandecan, S. et al; 2011, discuss how important features of dark speciality malts (e.g. Munich Malts), such as colour, flavour and reducing power, are mainly formed due to nonenzymatic browning reactions during the kilning and roasting process. The development of caramel-like flavour components is highly influenced by the roasting temperature and moisture content of the malt kernels.
References:
Briggs, D (1998). Malt and Malting. London: Blackie academic and professional. 713.
Gallagher, E (2009). Gluten-free food science and technology. Uk: Wiley Blackwell. 183.
Mayolle, J.; Lullien-Pellerin, V.; Corbineau, F.; Boivin, P.; Guillard, V. (2012). Water diffusion and enzyme activities during malting of barley grains: A relationship assessment. Journal of Food Engineering. 109, 358-365.
Woonton, B.; Jacobsen, J.; Sherkat, F.; Stuart, I. (2005). Changes in Germination and Malting Quality During Storage of Barley. Journal of the Institute of Brewing.
Vandecan, S.; Daems, N.; Schouppe, N.; Saison, D.; Delvaux, F.R. (2011). Formation of flavour, color and reducing power during the production process of dark speciality malts. Journal of the American Society of Brewing Chemists. 69 (3), 150-157.
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