Malt is the main ingredient used to make beers and ales, but what is it exactly? Malt is mainly made up of barley grains that has been made to slightly open making it easier to break the starch inside down to other sugars. But how is this made? Lets first go over the basics of how a pale malt is made.
Malt consists of partially germinated barley seed that have been dried and crushed. During germination enzymes are produced that convert the starch in the seed (flour) to sugar (maltose) which the yeast converts to alcohol. These enzymes are what we are using in the mash to extract the maltose and are destroyed at high temperatures which is why it is kept down below 70 degrees C.
The first step is Steeping. The grains are soaked in water and then allowed to breath in air for around 2 days. Sometimes the grain is kept in water and air is pumped through instead. The grain doesn’t want to be completely water logged just enough (around 40%) so that it begins to germinate and the grain opens up. At this point the malt is called green malt.
To help it germinate further it is transferred to a germination vessel or floor. This is a warm well light environment, the grain is turned either manually or by machine so it doesn’t overheat and dry out. Some more modern methods use fans and other devices to cool the grains. This can take up to a week and needs to help a steady balance by not getting the grains to the point where is starts to sprout and uses the starch up. By the end of the process more heat is applied to dry the malt. The green malt can now be referred to as modified green malt.
Finally kiln drying is the last standard step in creating malt. The temperature is slowly raised to help stop germination and finally to cure. Curing the malt takes place at high temperature and helps to preserve the malt thus keeping the quality high. This is the main step where we get a lot of variety in malts, so how are different malts made? Depending on temperature and air flow a different malt will be made. For example, Carmel and Crystal Malts are not dried before being put in the kiln and are heated at high temperatures and humidity straight away. This temperature is then raised further if it is a darker crystal malt. The large range of malts available show how many different variations of this can be done, but the basic process remains the same.
Some of you may also be familiar with malt extract, this is a syrup like version of a wort which many brewers use. To make three extra steps on the standard process are added, like you would do at home a mash takes place where the grains are soaked for some time to extract all we need for a wort. This is then filtered and evaporated to make the syrup like extract. 80% of the water content needs to be evaporated, dry malt extract takes even more out by using a centrifuge.
So making malt is actually a pretty complex multi-step process, something we have improved over time and found more and more ways to create new varieties of malt. It may seem like a simple ingredient but a lot more thought has gone into it over the history of brewing.