Grain Quality Is Key for Malting Barley Production and Marketing

Malting barley should not be grown as a grain crop, but instead should be considered as a crop grown for seed that must comply with food quality standards. If you are considering growing malting barley, it is important to learn how the crop will be processed to understand the quality parameters the industry requires.

How does barley become malt?

Once the crop is harvested, the seeds will be forced to germinate to produce malted grain. The germination process activates metabolic reactions within the seed that lead to the enzymatic breakdown of the starch into simpler compounds including glucose and maltose. The germinated seed is then dried.  The rootlets and germ are separated from the rest of the seed and used for animal feed. The malted grain will be milled and then mashed in hot water. The liquid will then be used for beer production, while the leftover grain (spent grain) can be used for animal feed.

What factors affect malting barley quality?

Malting barley quality can be affected by the variety, the environment, and their interactions. Field sprouting will negatively affect germination and the grain composition that is required for beer production. Other factors that affect grain composition and malt quality include the protein and moisture content in the seed, and fungal pathogens and saprophytes that affect grain in the field or during storage. Pathogens and saprophytes can cause grain degradation, reduce germination and in some cases, contaminate grain with harmful substances called mycotoxins.

Before you consider growing malting barley in Pennsylvania, there are a list of factors that must be considered:

Having a market: The first thing to do is to contact a maltster and have a contract before planting the crop. It is important to define where the grain will be stored, and the conditions for storage. Even the healthiest crop can be damaged if storage conditions are not optimal.

Expected quality standards: Beyond good yields, quality standards for barley intended for malting include percent germination of 90% or higher, moisture content below 13.5%, protein content in the range of 9.5% to 12.5%, varietal purity, plump and uniform kernels, less than 5% of peeled, broken and damaged kernels, and the lot must be free of inert materials, insects, and ergot (1). Another important quality factor is the Rapid Visco Analysis (RVA) result. The RVA indicates if enzymatic activity related to germination has already occurred in the seed from pre-harvest sprouting. The RVA value must be above 120 for the grain lot to be considered sound and able to remain viable after storage (3).

In addition to the aforementioned quality parameters, malting barley must comply with a maximum level of deoxynivalenol (DON, vomitoxin) of 1 ppm. Deoxynivalenol is a mycotoxin produced by the fungus Fusarium graminearum, the pathogen that causes the disease known as Fusarium Head Blight (FHB) wheat, barley and other small cereals (Figure 1).

Figure 1. Sign of Fusarium Head Blight on malting barley spikes (Photo credit: Adriana Murillo-Williams, Penn State)

Fusarium graminearum infects the crop mainly during flowering (Figure 2), and disease development will be favored by high relative humidity during this period. In addition to yield losses, grain contamination with DON can occur as a result of FHB.  Deoxynivalenol is heat stable and can undergo food and feed processing methods, therefore, it can enter the food human and animal chain in processed food, beverages, and feed (2).

Figure 2. Barley spikes A) Anthers and stigmas; B) Pollen shed from anthers. Photo credit: Adriana Murillo-Williams, Penn State.

Using varieties with some degree of resistance to FHB and applying a fungicide when more than 50% of the plants are heading can reduce disease severity and DON content. Visit the US Wheat and Barley Scab Initiative to sign up to get Fusarium Head Blight alerts for small grains. We also recommend looking at the  ScabSmart website for additional information about managing FHB and current recommendations by state. Lastly, visit the Fusarium Risk Tool during the growing for updates on the current and forecasted risk of FHB across the U.S.

Choose the right variety

In most cases, maltsters will require a specific variety to be grown.  If that is not the case, make sure you check the Penn State Barley Performance Trials and select a barley variety that has been specifically bred for malting. Also consider that it is adapted the local conditions (spring vs. winter barley), and that has adequate tolerance to FHB. It is always good practice to trial new varieties or production practices in small areas first to help familiarize yourself with their performance. Malting barley varieties should not be mixed under any circumstance to achieve consistent and acceptable quality values.

If you have questions regarding the content of this article, please contact Adriana Murillo Williams, Kristy Borrelli (kab617@psu.edu), Paul Esker (pde6@psu.edu) or Alyssa Collins (aac18@psu.edu) via email, or text Adriana Murillo Williams at 814-360-5517.

References

1. MacLeod, A. Understanding Malting Barley Quality. (Accessed on March 2, 2021)
2. Munkvold, G.P. (2017). Fusarium species and their associated mycotoxins. In A. Moretti & A. Susca (eds). Mycotoxigenic Fungi: Methods and protocols, Methods in Molecular Biology 1542, 51-106.
3. MacLeod, A. Decoding Malting Barley Quality. (Accessed on March 13, 2021)