Agriculture Reference
In-Depth Information
30
25
20
15
10
5
0
1982
1987
1992
1997
2002
Figure 1. Wheat as a percentage of the Scottish Cereal Acreage 1981-2005.
I
NTRODUCTION
There are two types of whisky distilled in Scotland [6]. For malt whisky, the sugars for
fermentation derive entirely from the enzymic activity of malted barley on its own reserves of
starch, whereas, in grain distilling, only a small proportion of malted barley, usually with high
levels of starch-degrading enzyme activity, is added to the mash. The rest of the cereal is in
the form of unmalted grain, cooked, under pressure, at high temperature to gelatinise the
starch. From the 1860s, the preferred adjunct was maize [78] due to its superior alcohol yield
per tonne of grain [77], but, during the 1980s distillers began to switch to wheat, largely for
economic reasons [49]. This change occurred quickly and, within 10 years, had already
created a demand of 450,000 tonnes per annum [72]. The opportunity to replace an imported
crop with a home-grown one had a major impact on wheat growing in Scotland, with a three-
to four-fold increase in the area under cultivation during the 1980s (Figure 1). Wheat is now
the second most widely-cultivated cereal in Scotland, after spring barley, occupying 20-25%
of the area sown to cereals [55].
However, the spectrum of varieties differs considerably from that required for
breadmaking. Distillers experienced processing problems if hard wheat was used [72] and
also noted a strong negative association between alcohol yield and grain protein content [49],
[73], so have restricted their intake to samples from soft wheat varieties, preferably of low
protein (nitrogen) content. One variety in particular, Riband, was used widely, due to its very
high alcohol yield [9], [69], but, for many years, distillers did not have many varieties to
choose from. Only four varieties were acceptable for grain distilling until 2003, when two soft
wheat varieties were added to the UK Recommended List [24], [69]. The absence of any
wheat breeding programme, specifically targeted at the distilling industry, was considered, in
part, to stem from lack of understanding of the genetic factors contributing to alcohol yield
Search WWH ::
Custom Search