Lesson 2 - Barley

The varieties of barley we malt today are different from those we malted centuries ago. These varieties have been developed to perform well on the farm, in the malt plant, and in the brewery. Through cycles of barley breeding and development, we seek to continually improve the barley that we grow and malt.    

Each country has a governing authority that oversees the breeding program. They ensure that tests are conducted before each variety is approved for malting for brewing or distilling. Malting authorities in some countries publish lists of approved malting varieties. Some of these lists also show the varieties that will be available in the future. Below are a set of links to the websites of some of these authorities where you can find the current approved varieties. 

Over many decades of research and testing, we have developed a deep understanding of the quality attributes important for malting, brewing, and distilling. We now understand how these attributes are affected by the environment in which barley is grown, and how they are linked to the genes of the variety. Even with this knowledge, extensive testing of newly developed malting barley varieties is still required.

The table below details the agronomic and malting attributes required from new barley varieties.

Table: Agronomic, malting and brewing attributes which are required from new barley varieties

Germination and dormancy

A grain must germinate for it to be malted. Any new varieties must have the potential for all grains to germinate in the malting process. However, a physiological attribute called dormancy may be bred into a barley variety. Dormancy is a natural property of a seed which aims to prevent it from germinating when the conditions for growth may not be right and stops the grain germinating on the spike. We want barley that is dormant while on the spike but not when we steep it. New varieties are developed to deliver barley that meets these criteria.

Protein content and composition

The protein level in a grain affects its suitability for malting. Higher protein grains have less starch so yield less sugar and therefore less alcohol. High protein grains also take up water less easily, so do not malt so rapidly or consistently. Some types of protein can also cause problems in the brewing process, whereas others are beneficial. It is therefore important that new varieties have the right level of the right proteins.

Starch content and composition

Starch is the most abundant material in barley. It is composed of thousands and thousands of glucose molecules. There are two forms of starch in barley: amylopectin, and amylose. Starch is the part of the grain that we are most interested in as it provides the sugar we ferment to get alcohol. New varieties of barley need to have large amounts of starch available when malted. Grains with higher starch content tend to have lower protein content.

Enzyme potential

Enzymes are key to both the germination of the grain and how well the grain converts starch into sugar in the brewhouse. With a low enzyme potential, the grain does not malt evenly. This creates poor yields and problems in the brewhouse. Having the correct enzyme potential is important for new varieties.

Extract potential

Extract potential is how much sugar we can expect to extract from the grain. This is a combination of the last three attributes:

• Low protein content
• High starch content
• Good enzyme potential

Barley with low protein content, high starch content and good enzyme potential has a high extract potential. Improving extract potential is a key ambition for barley breeding and development programmes.

β-glucan content

β-glucan is part of the aleurone and endosperm cell walls. Most β-glucan is broken down as part of the malting process, but some can remain and cause filtration problems in the brewhouse and later in the process. It is easier to make lower β-glucan malt from lower β-glucan barley. Therefore, any new varieties of barley developed should have low β-glucan, which can easily be broken down during malting.

Barley types in summary

• Winter and spring barleys are planted at different times in order to manage agricultural risk. That is, the variety is chosen and planted at a particular time based on farming needs rather than the needs of the maltster or brewer!

• Varieties are either spring or winter and either 6 or 2 row. Seeds are sold to farmers by variety and each variety has slightly different agronomic and brewing properties. Some brewers specify that their malt should be produced from a specific barley variety.