Evaluation of Hops Production in Maryland as a Sustainable Agricultural Enterprise

Results in 2018 is a difficult area to address because the weather was detrimental to our two primary cooperators and did not have time to follow through with submitting samples for testing as they had agreed to do with their portion of the grant money. The bright spot of this was however, with our aggressive management of the University of Maryland hop yard, we produced good yields and high quality hops and discussed below. This has influenced growers to look more closely at our research as they strive to improve their yield and quality. Thus, with our significantly higher yields and good quality of hops pellets we are beginning to be seen as a true asset and resource to the brewing community.

Observations of weather conditions in the hops yard began late December, 2017. We saw extreme cold from late December through mid-January with no snow cover and little moisture, which may have contributed to the loss of several Multihead plants. February through April were average for both temperature and moisture. We saw heavy rain in mid-May that resulted in downy mildew disease development, and a limited opportunity to apply a fungicide. Phostrol was applied, but it did not have adequate conditions or time to dry. At the end of May, there was a heavy infestation of leafhoppers, which blow in every year from the south. It depends on the weather patterns, but once they arrive, the population increases very quickly. They reduce the plant’s ability to photosynthesize and need to be managed quickly with an insecticide. That infestation was followed by another round of heavy rain at the beginning of June with a subsequent round of downy mildew.

The first three weeks of July were extremely hot and dry, causing a two-spotted spider mite outbreak, which required a heavy application of miticide to control. Then, the last week of the month saw 5½ inches of rain, a complete reverse of the weather patterns from the last three weeks.

From late June through mid-August, there was an abundance of Japanese beetles, managed with insecticide applications.

It should be noted that there are very few labeled crop protection products specifically for hops, making it difficult to find the right mix of products, but not impossible.

The 2018 season was an extreme reflection of Maryland weather. Heat and humidity were in full force, which set the stage for a similar amount of insect and disease development as we saw in 2017. What we have learned is that intensive care is paramount from the third or fourth week of June to early August, which is a small window for a perennial plant, in order for these plants to thrive.

This project is not only about growing excellent hops in sufficient quantities; they must be useful to craft brewers in the Maryland, so it is also about demonstrating scalable technologies to provide a high-quality product in a usable form to brewers. This meant harvest and post-harvest handling had to be an integral component of this experiment.

Timely harvest is critical and needs to be performed consistently and within a narrow window of time to ensure maximum quality and comparison of varieties. To facilitate this, Flying Dog’s investment in the partnership included joint funding of a mobile harvester. The harvester ensured that each variety was harvested in a timely and consistent fashion, and ensured the data collected on each variety regarding yield was (and will continue to be) consistent (Figure 1). As we discovered through this project, harvest times can vary year-to-year depending on weather conditions that have an effect on the hops maturity. As a rule, the cones should be harvested when moisture content reaches 25% (plus or minus 4%). Due to Maryland's unpredictable weather, this could stage hops harvest anywhere from late July to early September.

Compared to 2017’s harvest, which stretched from July 29 to September 8, the 2018 harvest was very quick. Most days we had to wait for the plants and ground to dry, so harvest wouldn’t start until early afternoon. Then, it was essential to get the cones into the dryer quickly because the moisture and humidity during the season was so high. This year, we used a dehumidifier inside of the dryer to get the moisture out of the hops as fast as possible (reducing moisture content from about 80% down to 8% in less than 24 hours).

As in 2017, the hops were processed on-site at the research facility after harvest. The hop cones were placed in the oast immediately following harvest and dried within 24 hours to 8% moisture. They were frozen in sealed bags using the liquid nitrogen system until they could be ground up in the hammer mill and then run directly into the pelletizer. The pellets were not heated above 110°F during pelletization, which required close attention. Once pelletized, they were placed in vacuum-sealed bags and frozen.

Most of the same processing techniques were used in 2018 to maintain best practices for processing hops and to minimize the number of variables in this project. Because the hops needed to be harvested in a shorter timeframe in 2018, they were vacuum-packed and stored in a freezer once they were dried. This kept them stable in between processing runs while we finished the harvest. Processing the hops cold also improved efficiency, an unexpected discovery out of necessity.

Samples of both dried cones and final pellets were sent to the Enology Analytical Services Laboratory at Virginia Tech for a complete analysis of oils and acids (Figure 2 and 3). A pre- and post-pelletization comparison showed how pelletizing impacts each hop’s composition. A typical brewer’s evaluation of hops in Yakima Valley does not include any of this quantifiable data—they are evaluated solely from a sensory standpoint. However, because this is a research-based project, we want to make sure our sensory analysis of UMD’s varieties matches up with quantifiable data on the composition of these hops. For the most part, our evaluations are aligning with the aromas and flavors that are typically associated with each hop oil. In the long term, this will help us identify patterns of oil compositions based on the ideal profiles for each variety.

Within a week of processing, Flying Dog received all of the hops from 2018’s harvest, except for the sub-samples that were sent to Virginia Tech for testing. To mimic how a brewer would use the hops in the typical brewing process (without brewing an individual beer with each), Flying Dog replicated its dry-hopping process by adding the hops to a light lager set to the same temperature as a dry hop. From there, Flying Dog’s trained sensory team did an aroma evaluation of the pelletized hops. Each evaluation was performed blind and panelists selected the top two hops out of five groups. Not only did the team evaluate aroma notes, they also noted the intensity of the aroma (Table 2).

Flying Dog’s final analysis of each hop combines the aroma and dry hop evaluations, with the dry hop evaluation weighted heavier because it a better indication of how the hops will perform in a beer. What was most interesting to the brewer was that Flying Dog’s team evaluation of the hops aligned with the oil breakdown data from the lab analysis.

The top rated hops from the 2018 harvest were:

• Vojvodina: Floral and melon aromas in 2018 and 2017, with the addition of a tropical and citrus pop in 2018.
• Southern Cross: In 2017, this hop exhibited a fruit punch profile, but 2018 brought more distinct citrus notes.
• Southern Brewer: This variety traditionally used for bittering, not flavor or aroma; however, this variety grown in the UMD trial possess brew qualities that align with the most popular hops coming out of the Pacific Northwest. Citrus, melon and resin dominate its profile.
• Glacier: Huge fruit and pine with subtle herbal and floral notes in 2018, compared to much more prominent resinous notes the year prior.
• Sorachi Ace: Lemon, citrus and spice profile mimics what is expected from this variety grown in other areas of the United States.
• Amallia: No yield in 2017, but the 2018 harvest brought a unique combination of tropical fruit and earthiness.
• Canadian Red Vine: While this hop had the best yield in 2017 and 2018, the profile is a less-desirable combination of onion, garlic and herb.

In comparison, the top hops from the 2017 harvest were Vojvodina, Glacier, Mt. Hood, Newport, Southern Brewer and Southern Cross. Vojvodina, Glacier, Southern Brewer and Southern Cross remained on 2018’s list, but Mt. Hood and Newport were replaced by Amallia, Canadian Red Vine and Sorachi Ace. The profile differences from 2017 to 2018 show how drastically some hop varieties can change as they reach maturity.

Another objective of this trial is to calculate the cost of production for Maryland hops to help farmers determine if hops are a viable enterprise. With that in mind, the two tables below outline the costs associated with establishing and maintaining the UMD ½-acre hops yard (Table 3 and 4).