Whisky creators have a broad spectrum of decisions to make, each carrying great weight in the eventual product’s profile, quality, and reception in the marketplace. Foremost among these choices is the fundamental process of selecting and malting barley. It’s the critical first step in the production of whisky.
This article explores what’s involved in malting barley, some different malting approaches, and why it matters.
Why “malt” cereal and how long does malting take?
Malting is performed on barley to unlock the potential fermentable sugars in the grains. This is essential for the yeast to feed on during fermentation.
Moreover, it paves the way for the unique flavours and aromas, setting the stage for the whisky’s individual profile.
The complete malting process, comprising steeping, germination, and kilning, takes approximately one to two weeks, including the necessary intermediate rest periods to allow for optimal enzyme development.
An overview of how the process works
Steeping
The process starts with steeping, where the barley grains are submerged in water to kickstart germination. A successful steeping process ensures a homogenous batch of swollen grains primed for germination.
The grains are soaked for a period of 40-48 hours with regular intervals to allow the grains to absorb moisture evenly, with the aim being a moisture content of about 42-45%.
The quality of water used is important, but far greater is maintaining a consistent temperature. This is usually kept between 12-16°C to ensure the right water uptake and prevent bacterial infections.
Germination
Following steeping, the barley needs to germinate for a period of four to seven days. Traditionally, this would happen on a malt floor, but in modern facilities it’s all done in specialised conical steel tanks.
The aim is to encourage the barley to sprout, which is key for the development of the enzymes that will be essential for the conversion of starches to sugars during the Mashing Process.
Maintaining a controlled environment with optimum temperature and humidity levels is essential to foster uniform germination. Regular turning of the grain bed ensures even temperature and moisture distribution, preventing heat build-up (hot spots) and mold growth.
Germination typically lasts 4-6 days. Distillers monitor the development of acrospire, the shoot that grows along the grain’s crease, to determine the germination’s end.
The aim of the gemination phase is to achieve a well-modified malt with sufficient enzymes to support the mashing process, (that transforms starches into fermentable sugars).
Kilning
The germinated grains, now termed ‘green malt,’ undergo kilning, a drying process. It’s a step that typically spans 24 to 48 hours. Kilning not only stops the germination but also fosters the development of flavours that become hallmarks of the whisky’s character.
Phases of Kilning:
- Free drying phase: Initially, low temperatures are applied to evaporate surface moisture without affecting the enzymes in the barley.
- Forced drying phase: Temperatures are gradually increased to eliminate bound moisture within the grains.
- Curing phase: At the final stage, higher temperatures are used to develop desired malt characteristics and flavours.
Temperatures typically range from 50-65°C in the initial stages to 80-105°C in the final curing phase. Distillers avoid sudden spikes in temperature to preserve the enzymes.
The total kilning process aims to reduce moisture content down to about 5%.
Floor malting vs. modern malting techniques
When it comes to malting, there are some notably different processes from the traditional floor maltings to technology driven modern solutions.
Floor Malting is the traditional approach. It involves spreading out the barley on the floor, turning it manually to ensure even germination. It requires significant manpower and time but offers a distinctive, often preferred, complex flavour profile owing to the in-depth control over the process.
There are mechanised maltings and other modern approaches, which are now more common. These include methods like pneumatic malting and drum malting, which are automated and control large batches of barley with precision.
While there’s little romance in them, they provide a high degree of consistency, stable production and cost savings.
For those who stick to floor maltings – and there are but a few remaining – the choice is not just the flavour profile of the outcome but also how it reflects the scale, philosophy, and tradition that the distillery wants to embody.
From the initial steeping to the delicate germination and the precise kilning, each step is a blend of science and heritage, culminating in the creation of a spirit that resonates with character and complexity.
As the barley transforms, it starts to shape the very soul of the whisky. Whether through time-honoured floor malting or modern mechanised techniques, the choice and execution of the malting process not only defines the whisky’s flavour profile but also embodies the spirit and tradition of the craft, marking the beginning of a remarkable journey from grain to glass.
