Plant breeders are continually developing new varieties of barley that outperform the existing range, enabling farmers to achieve higher yields per hectare while distillers gain higher yields of spirit per tonne. Developing new varieties requires significant investment but can bring serious financial rewards, as plant breeders retain ownership of the variety and earn royalties from seed sales.
It takes around six to 10 years of extensive trials by farmers, commercial maltings and distillers before a new variety is approved by the Institute of Brewing and Distilling (IBD). Each year the IBD's Malting Barley Committee announces which varieties are approved for use in the following year. Barley varieties are initially given Provisional Approval 1, which may lead to Provisional Approval 2 or even Full Approval, but only if confirmed by additional test results.
Varieties approved for 2012 are Optic, Concerto, Oxbridge and Belgravia. Each variety has varying potential, with average yields being Concerto at around 5.7 tonnes per hectare, Oxbridge and Belgravia 5.5 tonnes, and Optic 5.3 tonnes (for comparison Golden Promise, which reigned supreme from the 1960s to the 80s, was around 4.5-7 tonnes per hectare).
However, each variety depends on the climate to attain an optimum yield, and each variety has different susceptibilities to weather patterns (and disease).
Steady rainfall is ideal when barley is sown in March-early April, whereas a drought would restrain development. Sunny weather is key from late June-early August when the barley starts building up its starch content through photosynthesis, whereby light is used as an energy source to create starch from water and carbon dioxide (drawn from the environment). As photosynthesis occurs during daylight, Scottish summers provide the significant advantage of up to 18 hours daily. Moreover, the sunnier it is the greater the rate of photosynthesis and build up of starch (and the higher the starch level the greater the resulting yield of spirit).
"Rainfall is generally higher in the north and west than the Borders. However, heavy rain during the 2009 harvest caused various problems in the Borders, whereas most of northern Scotland missed the bad weather"
Barley varieties are classified as ‘early’ or ‘late’ harvest depending on when they ripen, with early varieties usually harvested in August, and late harvest in September. Optic and Oxbridge are late harvest, with Concerto and Belgravia later still.
Harvest dates for the same variety are usually one to two weeks later in the north of Scotland than further South, particularly in the Borders, which can be crucial in September when the weather is more changeable. However, farmers only need ‘windows’ of two to three days at a time of dry, still conditions to harvest, and any rain in between isn’t an issue.
Rainfall is generally higher in the north and west than the Borders. However, heavy rain during the 2009 harvest caused various problems in the Borders, whereas most of northern Scotland missed the bad weather. But even within the north there can be significant differences in rainfall between The Black Isle and Stonehaven. Consequently, even the same barley variety will show varying results depending on the micro-climate where it was cultivated.
A key statistic for distillers is the PSY (Predicted Spirit Yield) of each variety. Concerto leads at around 410-420 litres per tonne, with Optic and Oxbridge around 405-415 litres (Golden Promise at around 380-395 litres shows how yields have risen). However, the PSY is only an average attained in a lab. The ASY (Actual Spirit Yield) in a distillery can vary significantly depending on where the barley was cultivated, while annual variations in the same variety reflect each year’s climate.
Another consideration is whether any variety can contribute individual characteristics to the spirit, beyond generic cereal notes?
“Even if a variety can make an individual contribution this would be very minor compared to fermentation and distillation which are the key determiners of spirit character. Moreover, any potential influence from a barley variety would become even more marginal in the resulting malt whisky, as maturation accounts for a great part of a malt’s character,” says Dr Bill Lumsden, head of distilling and whisky creation at The Glenmorangie Company.
Distillers can purchase malted barley from commercial maltings on the basis of annual contracts concluded in October-November, once the harvest and prices are known. This might suit a distiller requiring smaller amounts. Alternatively, longer term contracts provide a guaranteed supply which certainly suits distillers placing larger orders, with prices reflecting quantities ordered.
Optic has been the leading barley variety since 2000, partly because it copes so well with adverse weather.
Eleven years at the top is remarkable considering some new varieties may only remain on the market for a few years years before the next generation comes in. However, Concerto is becoming a serious rival to Optic, which is an impressive feat as Concerto only gained Provisional Approval 1 for use in 2010, with highly successful test results leading to Full Approval for 2011.
Whether Concerto makes it to number one, and how long it may reign there, remains to be seen.
Malt whisky is distilled from varieties of spring barley (sown March-early April and harvested August-September) as opposed to winter barley (sown August-September and harvested the following late July-early August). Spring barley usually has higher starch levels than winter barley, and as starch levels determine the yield of alcohol spring barley yields about 1.5-2 per cent more spirit than winter barley.
Scotland produces sufficient spring barley to cater for the malt whisky industry, with current planting around 250,000 hectares. This total has fluctuated between 216,000- 287,000 hectares during the past 20 years. However, average spring barley yields in the last 10 years have been around 10 per cent higher than the previous 10 years, with the average yield now 5.5 tonnes per hectare, according to Scottish government figures.