The use of barley in Single Malt Whisky production
Single Malt Whisky is produced from three main ingredients, barley, water and yeast. Why Barley?
Because, barley was one of the first cultivated grains. It was one of the first materials used for alcoholic fermentation and most probably it was readily available at the space-time where the whisky production took place.
Why it is still used? Barley has high content of starch and the necessary enzymes to convert the starch into sugars.
Barley is "malted" by soaking the grain in water for two to three days and allowing it to germinate. This process releases enzymes, which convert starch (which is insoluble in water and not available for fermentation by yeast) to fermentable sugars.
The mash of the malted barley will be transformed to beer, and after the distillation to the "New Make Spirit".
Traditionally, barley was grown on site at the distillery or purchased locally from farmers. Over the years more economically viable ways were developed in the production of barley.
Malsters took over the growing and malting process in large-scale processes selling bulk quantities of malt back to the distillers. Distillers have the important job of picking quality barley for production; this plays a big part in the final quality of the whisky.
The distilleries select their barley according to a set of technical criteria rather than variety. The most important are the corn size, nitrogen, moisture and content.
All barley used for malting is air-dried after harvest, taking its moisture content from 20% down to 12%. Next, it is graded for size and cleaned, then cooled over a period of months from 20c to 5c. This temperature change causes the grain to start preserving itself, ready for us to trick into thinking it's in the ground and warm, ready for germination.
Even though the distilleries have high standards for the selection of barley that they are going to use, the variety of the barley rarely appears on the label. This is due to the fact that barley's contribution to whisky flavour is less than it will be in beer. The whole procedure, from malting, fermentation and distillation to maturation, filtering and bottling remove and transform most of its characteristics, consequently the difference between varieties is less obvious when it comes to flavour.
Barley is a member of the grass family. It is a self-pollinating, diploid species with 14 chromosomes. The wild ancestor of domesticated barley is Hordeum vulgare subsp. There are over 300.000 varieties of barley in the world categorized in two distinct forms, "two row" and "six row".
Two-row barley has lower protein content than six-row barley, thus more fermentable sugar content. High-protein barley is best suited for animal feed. Malting barley is usually lower protein ("low grain nitrogen", usually produced without a late fertilizer application) which shows more uniform germination, needs shorter steeping, and has less protein in the extract that can make beer cloudy. Two-row barley is traditionally used in English ale-beers.
In the mid-19th century, a typical malt distillery would turn 8 gallons of malted Archer or Gold-Thorpe barley into 2 gallons of spirit. Nowadays you need 1kg of barley to make a 70cl bottle of whisky. These improvements in yield can be partly attributed to better production methodology and machinery but over the past 50 years the yield has increased by 30% whiled the machinery remained relatively unchanged.
In 1965 a revolutionary barley variety was developed called Golden Promise, an English semi-dwarf, salt-tolerant and mutant variety (created with gamma rays). It's hardy, fast maturing and superior malting attributes made it the choice barley for distillers for nearly twenty years. Up until then the class of barley had been rather mediocre. Towards the end of the 20th century new varieties of barley had been bred with all the attributes of Golden Promise but giving higher yields, popular examples are Optic, Decanter and Chariot. Off course the new generation varieties are already in the pipeline like Odyssey and Chronicle.
The increase in whisky sales worldwide has led to soaring demand for quality malting barley.
Generally the limiting factor to growing grain in Scotland is the wet, cold conditions. Nevertheless, about 500,000 hectares of cereal crops are grown with more than half of that land dedicated to growing spring barley. The region produces about 1.7 million tonnes of barley a year, compared to Australia's average annual production of around seven million tonnes.
Scotland can't supply all the barley needed to keep the distilleries running so maltsters are now encouraging more English arable farmers to grow grain specifically for the whisky industry. In addition significant quantities are imported from France and the Netherlands.
Malt barley prices are variable but a lot of contract barley has sold at £170 per tonne for malt the past year.
....Too much info! Let's have a dram!
Co-Founder of www.singlemaltlodge.com