Does Scotland’s distilling industry need to think ‘hard’ to reach sustainability targets?

Does Scotland’s distilling industry need to think ‘hard’ to reach sustainability targets?

31st October 2023

Greg Dawson, Deputy Managing Director at Scottish Agronomy, takes a look at a different way for the supply chain to meet sustainability goals as weather and disease plays havoc with a traditional distilling variety.

Growing cereals in Scotland is becoming more complex, challenged as we are with how chemistry deals with disease and changing weather patterns. Selecting varieties with appropriate traits is more important than ever.

Growers will have chosen which varieties to sow this autumn whilst pondering what each variety will bring with respect to margin over input cost and end user demand. Does the industry as a whole need to work together to create a more holistic and long-term approach to wheat sourcing and management of varieties for distilling?  

Traditional view to attributes of distilling wheat

  • Soft grain texture
  • High alcohol yield
  • Efficient processing
  • Agronomically competitive
  • Minimise environmental impact

Some of the stalwart winter wheat varieties are not performing as they used to. They are frequently less predictable in their response to disease and weather, and many of our members have been questioning what risk they are prepared to carry.

The supply of soft distilling wheat could be challenged as growers decide whether to stick with existing varieties which may need higher fungicide spend and ultimately be lower yielding or to try something new. Variety choice is crucial.

There’s currently a lack of commercial trials on new distilling winter wheat varieties compared to spring barley, largely driven by the fact that a meaningful run in a continuous grain distillery may need 1,000 tonnes.  This probably requires the variety to be on the Recommended List and to already be grown commercially – a catch 22.

What’s interesting and exciting is that, while the supply chain has tended towards soft wheats for distilling, recent trials we’ve initiated suggest there could be merit in bringing hard wheats into consideration to provide options for growers whilst moving towards the green credentials of the distiller.

A sliding scale

Distillers have historically preferred using soft wheats over hard wheats due to traditionally better alcohol yield production, easier milling, and good processability. In the 1990s and early 2000s, when hard wheat was occasionally used, there were significant processing difficulties. Some of this was linked to the hard wheat 1b/1r gene but not always – it’s worth noting that modern hard wheat varieties are no longer bred from lines containing the gene.

Grain distilleries thrive on consistency and swinging between soft and hard has always seen as a significant negative – hence the present preference for soft wheat varieties.  With that said, hard and soft is a continuous scale, with some soft wheats lying nearer the hard end of the scale. Conversely, some hard varieties produce high alcohol yields but are currently being overlooked.

The crunch is now here on farm, where the yield gap and disease susceptibility between hard and soft wheats has opened. We may see the gap narrowing again as new varieties come through, but growers are left carrying the risk in the interim and the whole supply chain could be missing opportunities.

Distilling down the evidence

Any variety tested for distilling must have its alcohol yield potential assessed in multiple replicated field trials. Equally some of the significant questions about hard wheat can only be addressed by end user engagement.

A selection of hard and soft wheat varieties grown in our trials were independently tested last year for their alcohol yield production, and residue viscosity. The samples came from replicated trials with identical inputs. Two of the hard wheat varieties tested gave between 6 and10% more alcohol per hectare than a control soft wheat which dominates the market.

The increase was due to higher alcohol production per kg of grain and higher yield. This goes a long way to reducing end users’ Scope 3 indirect greenhouse gas emissions that occur because of an organisation’s activities but are outside of its direct control.

All the wheats tested gave acceptable levels of residue viscosity but it isn’t all upside. Importantly, the hard wheat tested had higher peak viscosity and a slightly higher pasting temperature which indicates that the mash may require higher temperatures to process successfully.  In modern distilling, many grain distilleries process at lower temperatures to make energy savings and reduce emissions. How hard wheats would respond to lower temperatures in a distillery is still untested but there is an opportunity for distillers to directly partner parallel work in future.

More than just cutting nitrogen

On a similar note, the headline of simply cutting back nitrogen to reduce carbon footprint is potentially flawed. If you undersupply a crop, you could be reducing the yield and quality with little, or even a negative effect, on the greenhouse gas emissions per tonne of grain.

We can miss opportunities by simply not looking in more detail at each stage of the supply chain.

At Scottish Agronomy, we are laying down specific trials to evaluate what the consequences are of different decisions, so the whole supply chain can decide how to best decarbonise the industry and run profitable businesses.

Different wheat varieties have different alcohol levels and different yields; we’re also looking at the science behind cover cropping, soil health and crop nutrition through replicated trials. If we can identify the best varieties and crop management for growers to get best yield, with the lowest carbon emissions, for the distillers to process, we are all a step ahead.

Scottish Agronomy has over 20,000 trials plots over 12 geographically spread trials sites across Scotland, testing different varieties and treatments for crops including wheat, barley, oats, oilseeds, linseed, rye, triticale and cover crops.


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