MALTING, BREWING AND DISTILLING 221 6-8d o-35d 4-6d B863-7d 3-6d 3-6d 3 d IG9.3 Diagram showing the reduction, over three centuries, in periods needed for malting a nree stages involved in the process century, and that savings are made in all stages,(say 1.8% N), destined for a vinegar factory, although the greatest benefits have been achieved 46-49% m/c may be preferred. Higher moisture in the germination stage levels induce faster modification but greater losses are incurred(Briggs, 1978). Anaerobic condi tions are dangerous as they favour fermentation by micro-organisms present. The ethanol pro- Traditional malting included a ditch steep duced can harm the grain. On the other hand followed by germination in heaps on the floor. It excessive aeration leads to chitting under water was a labour-intensive proc he heaps or and, consequentially, an undue rise in moisture couches'required frequent turning. It was also content. time consuming It is desirable to replace steeping water with Current practice varies according to the size fresh, between 1 and 4 times, as phosphates of operation and the preference of the maltster and organic compounds, including alcohol, accu- but self-emptying steep tanks have replaced the mulate and the microbial population grows ditch steep Vessels may be fat-bottomed or During the first steep dissolved oxygen conical-bottomed tanks. They have facilities for depleted from steep-water at a rate of l mg/ water filling and emptying, and compressed air kg per hour but it rises 10-fold by the third blowers provide both aeration and 'rousing and steep Complete depletion is possible within one mixing during the steep. Together, these pro- hour. Temperature is controlled to a degree cesses combine to remove carbon dioxide which by the water temperature to between 10 and accumulates as a result of respiration of grains 16.C and micro-organisms associated with them vigo There are many variations in steeping practice rous aeration immediately after discharging the including steeping in running water(Bavarian barley into the steep tank also serves to raise and the ' flushing regime in which immersions dust, chaff and light grains to the surface for are frequent but cover the grains for only a few removal. These are accumulated and sold for minutes. Modern steep tanks are filled with barley to a depth of 1.2 m. This increases to Aeration, damping and temperature have to 1. 8 m when the grain is swollen. The uniform be carefully controlled in order that germina- depth of flat-bottomed tanks provides for more tion occurs at the required rate and to the uniform aeration and coz removal than in conical required degree, For poorly modified traditional bottomed vessels pale lager, European 2-rowed barley needs Following steeping, the grain is transferred to steeping to 41-43%m/c, while for a pale-ale malt germinating vessels. This may be by ' wet-casting 4345%is appropriate For a high nitrogen barley whereby it is pumped in water suspension or1686 1886 Germinate Kiln IO-35d 4-6d Steep 6-8d - 3-7d 8-28 d 3-6 d -