Home / Sustainability

Malting Barley Sustainability

Resource efficiency, climate resilience, and environmental performance across the barley-to-malt supply chain.

Sustainability overview

Why sustainability matters in malting barley

Malting barley sits at the intersection of agriculture, food and beverage production, and environmental responsibility. As breweries and maltsters face increasing pressure to reduce their environmental footprint — from consumers, investors, and regulators — the sustainability of the raw material supply chain has become a strategic priority.

The sustainability of malting barley can be assessed across three main dimensions of resource use: water, nitrogen, and energy. Each of these inputs generates environmental costs and each can be optimized through better agronomy, variety selection, and management practices. Together, they contribute to the carbon footprint of the malt and, ultimately, of the beverage.

Sustainability in the barley-to-malt chain is not simply about reducing inputs. It is about getting more value — more yield, more quality, more environmental benefit — from each unit of resource used. This concept of resource efficiency is central to both economic and environmental performance.

Water Use Efficiency
WUE
kg grain per mm of evapotranspiration. Key in irrigated and drought-prone systems.
Nitrogen Use Efficiency
NUE
Yield per unit N applied. Balances grain yield and malting protein targets.
Energy Use Efficiency
EUE
Malt output per unit of energy input. Critical in kilning operations.
GHG Emissions
CO₂e
Tonnes CO₂ equivalent per tonne malt, across the full chain.
Water management

Water Use Efficiency (WUE)

Water Use Efficiency (WUE) is the amount of grain yield obtained per unit of water used by the crop. In malting barley, WUE is important because it helps explain how efficiently the crop converts water into grain under different climates and management systems.

How WUE is measured

WUE is typically expressed as kilograms of grain yield per millimeter of water evapotranspired (kg/mm or kg/ha per mm). In irrigated systems, it can also be expressed as yield per volume of irrigation water applied (kg/m³). The two most common ways to report WUE in barley are:

  • Crop WUE: grain yield / total evapotranspiration (ET)
  • Irrigation WUE: yield increase from irrigation / volume of water applied

Why WUE matters for malting barley

Water scarcity is increasing across major barley-producing regions. In Australia, Spain, Chile, Argentina, and parts of North Africa, rainfall variability is the primary constraint on yield. Varieties and management practices that maintain yield under limited water availability — or achieve the same yield with less water — are critical for long-term viability.

WUE is also directly linked to protein content: water-stressed crops often show elevated protein levels, which can push grain above the maximum protein threshold for malting specifications. Managing WUE therefore has dual implications — agronomic efficiency and malting quality.

Typical WUE values: Malting barley in rainfed Mediterranean-type environments typically achieves 8–16 kg grain per mm of evapotranspiration. In well-managed irrigated systems, WUE can reach 18–25 kg/mm. Breeding targets increasingly include WUE as an explicit selection criterion.

Improving WUE: key strategies

  • Variety selection: Varieties with deeper root systems, better transpiration efficiency, and stress-tolerance mechanisms show superior WUE under limited water.
  • Sowing date optimization: Aligning crop growth stages with soil moisture availability reduces the need for irrigation.
  • Deficit irrigation: Applying water precisely at critical growth stages (tillering, grain fill) rather than uniformly throughout the season.
  • Soil management: Cover crops, reduced tillage, and organic matter additions increase soil water-holding capacity.
  • Precision irrigation: Drip and sensor-driven irrigation systems match application to real-time crop demand.
Nutrient management

Nitrogen Use Efficiency (NUE)

Nitrogen Use Efficiency (NUE) measures how efficiently barley captures, absorbs, and converts nitrogen into grain yield and malting quality. In malting barley, NUE is particularly complex because nitrogen management must balance yield (which benefits from higher N) against grain protein content (which must stay within strict limits for malting).

The NUE components

NUE in barley can be decomposed into two sub-efficiencies:

  • Nitrogen uptake efficiency (NUpE): the proportion of soil-available nitrogen that the plant actually absorbs
  • Nitrogen utilization efficiency (NUtE): the yield produced per unit of nitrogen absorbed

Agronomic NUE = grain yield / nitrogen applied. It captures the combined performance of both sub-efficiencies. A crop achieving 6 tonnes/ha from 80 kg N/ha applied has an agronomic NUE of 75 kg grain per kg N.

NUE componentFormulaWhat it measures
Agronomic NUEYield / N appliedOverall efficiency of N input into grain production
N uptake efficiencyN absorbed / N appliedHow much applied N the plant captures from the soil
N utilization efficiencyYield / N absorbedHow efficiently absorbed N is converted to grain

The protein challenge in malting barley

Excess nitrogen application raises grain protein content above the 11.5% threshold typically specified for malting. High protein malt creates problems in brewing: elevated haze potential, reduced extract, and impaired filtration. This creates a unique challenge in malting barley: unlike feed crops where high protein is desirable, high nitrogen inputs may actually reduce the commercial value of the grain.

Optimizing NUE in malting barley therefore means applying the right amount of nitrogen at the right time — enough to support yield and malt quality without raising protein beyond specification. Split applications (early base dressing + late topdress based on crop sensing) are increasingly standard practice.

NUE and sustainability

Nitrogen fertilizer production accounts for a significant fraction of the carbon footprint of barley. Ammonia synthesis via the Haber-Bosch process is energy-intensive, contributing approximately 1.5–2.5 kg CO₂e per kg of nitrogen fertilizer produced. Improving NUE directly reduces both the economic and environmental cost of nitrogen in the crop system.

Energy performance

Energy Use Efficiency in Malting

Energy consumption in the barley-to-malt supply chain is concentrated in two main areas: agricultural operations (field machinery, irrigation pumping, fertilizer production) and the malting plant itself — particularly the kilning process.

Energy in the malting plant

Kilning is the most energy-intensive step of the malting process. The drying and curing of green malt typically consumes 900–1,400 MJ per tonne of finished malt, depending on technology, fuel type, and process efficiency. Major sources of energy in modern malthouses include natural gas or liquefied petroleum gas (for kiln heating), electricity (for fans, conveyors, refrigeration), and steam.

Energy efficiency improvements in modern malting include:

  • Heat recovery: Capturing exhaust air heat from kilns to pre-warm incoming germination air or steeping water
  • Variable speed drives: Matching fan speed to actual airflow needs during germination and kilning
  • Modern kiln design: Horizontal kiln floors, computer-controlled airflow profiles, and improved insulation
  • Renewable energy integration: Solar thermal, biogas from malt processing waste, and green electricity procurement
  • Process optimization: Reducing germination time through variety selection and enzymatic pre-treatment

Best-practice benchmark: Leading malthouses achieve total energy consumption of 900–1,050 MJ per tonne of malt, compared to an industry average of 1,100–1,400 MJ/t. The gap represents a significant decarbonization opportunity across the sector.

Renewable energy in malting

The transition to renewable energy is accelerating in the malt sector. Several large malthouses have committed to net-zero malting operations by 2040–2050, driven by brewing industry sustainability targets. Key strategies include electrification of heat with green electricity, biomethane from agricultural waste, and on-site solar generation for ancillary loads.

Farming systems

Regenerative and Organic Approaches

Regenerative agriculture and barley

Regenerative agriculture refers to farming practices that restore soil health, increase biodiversity, and build soil carbon. In malting barley systems, key regenerative practices include reduced or no-tillage cultivation, cover cropping between barley seasons, integrating livestock grazing into rotations, and minimizing synthetic input use.

Regeneratively managed barley fields often show improved soil water retention, reduced erosion, and lower synthetic nitrogen requirements — all of which contribute to improved WUE, NUE, and lower carbon footprints over time.

Organic malting barley

Organic malting barley is produced without synthetic fertilizers or pesticides. Nitrogen is supplied through organic matter (composts, manures) and biological nitrogen fixation from legume cover crops. Yields are typically 20–40% lower than conventional systems, but premium prices and lower input costs can maintain profitability.

Key challenges in organic malting barley include achieving consistent protein levels in the target range, controlling disease without fungicides, and meeting the strict germination quality requirements of maltsters. Specialty craft brewers and organic beer producers drive niche but growing demand for certified organic malt.

Explore the carbon footprint