The Malting Process
What is Malt?
Malt is one of the raw materials utilised by brewers & distillers for the production of beer & certain spirits.
Barley (or other cereal grains such as wheat and oats) is turned into malt by allowing the grain to germinate under controlled environmental conditions, and then hot air-dried to develop the characteristic flavour and colour.
Starch contained within the malted barley is later converted into fermentable sugars in the brewing process. As well as starch, the malted barley also contains enzymes, proteins, vitamins & minerals.
There are three main stages of the malting process: Steeping, Germination, and Kilning.
Way Back When
Did you know that the Egyptians were brewing beer in 4000 BC and artifacts in the Cairo museum show that it had already evolved into a disciplined technology by the third millennium BC?
Beer can be brewed from a range of cereals, but by the 17th century, beers were brewed from malted barley, predominantly in Europe. With the expansion of trade and the discovery of the New World, making beer from malted barley spread across the globe.
The purpose of the steeping is to increase the moisture in the grain so that germination can be initiated. The steeping process can take up to 2 days and consists of the grain being immersed in aerated & attemperated water.
The water is then drained off and the grain rests whilst air is drawn through and the carbon dioxide is removed. The goal is evenly hydrated, germinating grains.
After steeping, the grain is transferred and distributed evenly throughout within a germination vessel. During the germination process, the grain is grown under carefully controlled conditions, in which the moisture, temperature, and airflow parameters are carefully manipulated. The germinating barley is also periodically “turned” or mixed to promote a homogeneous product.
It is during this stage where barley is ‘modified’ and converted into “green malt” ready for kilning. The germination phase can take up to 4-5 days, depending on the product being made.
Kilning involves the use of heated air to dry the grain in order to produce a stable product that can be easily stored and milled. Large volumes of hot air are blown through the evenly loaded grain bed.
By varying air flows and kiln temperatures, the maltster can control the desired flavour and colour profiles of the malt. Depending on the type of malt being produced, kilning can take up to 24 hours.
Roasting takes place in a roasting drum which can hold a batch size of 2.8 to 3.6 tonnes. The average roasting time is 2 ½ – 3 hours with an air temperature of up to 250°C, dependent on the product being made.
The roasted product is then transferred to the cooler where its temperature is reduced to fix the colour and flavour compounds. The malt is analysed before storage and thereafter awaits dispatch to our customers.