Save the Date – Final 2017 Workshop

Our final workshop of the season is quickly approaching. Are you thinking seriously about putting in a hop yard? Are you currently growing hops and looking to expand your yard and knowledge? This workshop may be for you. Make plans to join us Saturday, November 4, 8 a.m. – 5 p.m.

Presenters will cover every detail between selecting a site for a hop yard to post harvest practices. More specific topics include:

  • Botany & Chemistry of Hops
  • Environment, Site & Soil Requirements
  • Integrated Pest Management, Diseases, Nutrients & Weeds
  • Building a Hop Yard/Country Club Build Out video
  • Water Requirements & Irrigation
  • Harvesting, Picking & Drying Systems
  • Processing, Packaging & Storage
  • Production Timeline
  • The Real Costs of Hop Production
  • Open Panel Discussion

The workshop will conclude a tour of Midwest Hop Producers, weather permitting.

The cost of the full-day workshop is $150, including lunch. To register, follow the link here. For questions, please contact Katie Kreuser, at katie.kreuser@unl.edu or 402-472-3036.

 

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Post Harvest Hop Yard Management

Harvest 2017 is in the books, and there’s a nip in the air that hints that the fall equinox is not far away. Take a deep breath and relax as the to do list around the hop yard grows small in preparation for winter.

Post Harvest Agronomic Practice Recommendations

Bines, 2nd year and older, should’ve been cut back to 2-3 feet above the ground at harvest. Following the first hard frost and at least 4-6 weeks after harvest, bines can be cut to a few inches above the soil. For 1st year plants and older, aerial shoots should be removed, especially if disease pressure was significant in your yard. First year bines can remain through winter or cut back with everything post frost. Plant material should be buried, burned or if disease was not present on bines, they may be fully composted.

Use this time to get control of weeds present in your hop yard. Herbicides such as Volunteer for grasses and Aim for broad-leaf weeds. Weeds provide another shelter for fungal structures to overwinter so get a head start on next season by removing them!

If your hop yard’s soil is primarily clay, you may want to take time in the fall to hill your plants. It’s also a great time to incorporate compost to replace some of the nutrients lost when hops are harvested. Soil along either side of the plants may be lightly tilled, incorporated with composted, then piled a few inches on top of the crowns. This may help to reduce chances of winter kill and kill off downy spores present in the soil. “Hilling” is a great way to improve drainage for the following season as well.

Once harvest is complete, drip irrigation should be backed off to a couple times a week at most. Growers should keep the yard on the dryer side, especially as downy mildew spores require moist soils to survive. You may find that rainfall and cooler temperatures provide sufficient moisture.

Post Harvest Pest and Disease Management

For effective management of pests and diseases all season long including post harvest, we have to look at the individual life cycles of each pest or disease. We’ll take a closer look at some of the problems we’ve had across the state:

Downy mildew. The pathogen causing downy mildew survives in the form of mycelium in plant debris and in the crown of hop plants, emerging in the spring on infected flag shoots. In the spring, mycelium develop spore bearing structures which release zoospores. Zoospores travel via the wind or rain drops, and can infect new stems, leaves and flowers, over and over throughout the season. Mild, rainy weather in the spring makes for the ideal downy mildew infection.

Since the pathogen can be harbored in debris, all debris should be removed, and buried or burned. Because the pathogen can overwinter in the crown as well, a systemic fungicide that will move down the plant may be applied. Aliette or a phosphite based fungicide are options. With little leaf tissue for application, and little research to support these applications, a better bet for those with downy infections in the 2017 growing season should use the winter to develop an aggressive protective program for the 2018 season.

Potato leaf hoppers. Potato leaf hoppers overwinter in the southeast region of the United States. Their migration north and west occurs in spring or summer storms. For this reason, there is no management needed post harvest for potato leaf hoppers.

Aphids. Aphids breed and over winter in the bark of Prunus species, such as apples, apricots or peaches. As the weather cools, aphids will mate and move back to a Prunus species to lay eggs and overwinter. No post harvest management is recommended.

Spider mites. The advantage in treating spider mites post harvest is that when hop bines are removed at harvest, most of the spider mites are removed at the same time since they’re removed fairly early in the season. Some mites will remain in plant debris or in the trellis posts for the winter. Post harvest treatments are not generally recommended unless infestations reached devastating levels. Scout your yard, counting mites per leaf. If 10+ mites are present on average per leaf, a post harvest miticide application is recommended.

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Take a moment to reflect on the season, what you did that worked well, and what you will do better next year. I hope you will reap the benefits of your labors this season with a fresh harvest ale in your near future!

Hop Powdery Mildew

Many growers in Nebraska have become familiar with downy mildew, a fungus caused by Pseudoperonospora humuli, which was responsible for wiping out most of the United States hop production in the early 1900’s. The fungus Podosphaera macularis causes another significant disease on hops worldwide – powdery mildew. Until recently, it had not been confirmed in the state of Nebraska. It’s arrival is never timely, and as growers, everyone should pay extra attention in scouting. Like downy mildew, powdery mildew can cause complete loss of yields due to crop failure or poor cone quality. With recent cooling temperatures, dense fog in some areas in the early mornings, and some cloudy days, powdery mildew has been dealt the perfect weather card for infection.

Luckily, while many growing areas report findings of powdery mildew, the disease has not established itself as a common problem in the non-traditional growing regions. To prevent major infestations, scouting and an accurate diagnosis is critical once it presents itself. Sourcing disease free nursery stock is particularly important to prevent introduction of the disease.

Signs and symptoms

Powdery white colonies of the fungus can appear on any surface of hop plants — leaves, buds, stems and/or cones. Infections on flowers or cones will often cause malformed cones or prevent cones from forming altogether. White, powdery fungal growth may appear on developing cones, or in some cases, may only be visible under the cone’s bracts with magnification. As cones die, they will turn red-brown in color, or very pale green or light brown after drying. Generally, powdery mildew remains on the surface of hop plants, except with its haustoria (small structures that feed on epidermal cells). If you think you have powdery mildew, please submit a sample to the UNL Plant and Pest Diagnostic Clinic for verification.

IMG_2989

IMG_2986

Powdery white colonies on Yakima Gold hops in Eastern Nebraska in early September 2017.

PMCollage

Photos on hop powdery mildew affecting cones. (Washington State University)

Life Cycle

The life cycle of the hop powdery mildew pathogen differs based on regional presence. In all regions including the PNW, it survives through overwintering in dormant, infected buds, and reproduces asexually. It emerges in flag shoots in the spring from the crowns, then spreads through spores called conidia in spring rains or wind.

East of the Rocky Mountains, the pathogen is capable of reproducing both asexually and sexually. This means that in addition to overwintering in infected buds, it may also overwinter in the form of a sturdy structure called a chasmothecia in crop debris from the previous season. Because of our location, burying or burning plant debris is essential to the cultural control of this disease. These chasmothecia structures will release infectious spores in spring rains.

The ideal weather for powdery mildew infections include high humidity, temperatures between 50 and 82 degrees F, cloudy weather and rapid plant growth. The cycle can complete in as short a time as 5 days. The growth points, especially burrs and cones, are most susceptible to infections because they can be damaged and cause a loss in yields.

hop PM life cycle

Life cycle of Podosphaera macularis on hop. (Prepared by V. Brewster) [As appears in the Field Guide for Integrated Pest Management in Hops, Third Ed. 2015]

I found powdery mildew. What do I do now?

Before proceeding, ensure that powdery mildew has been confirmed in your hop yard. There are a variety of strains of powdery mildew that could be present in your hop yard. Late season infections look similar to Alternaria cone disorder or gray mold. If infections have reached economically damaging levels, remove all plant material above 5 feet of each bine, and apply stylet oil or Omni Supreme Spray, which have been shown to be effective on populations of powdery mildew in Michigan hop yards. Spraying a protective fungicide such as Quintec or Pristine are also options.

After plants have reached complete dormancy, remove any plant debris where the fungus may overwinter. Discard debris by burying or burning. Do not compost. Reapply stylet oil or omni supreme spray.

In early spring, the first bines to emerge should be chemically or mechanically removed. Scouting and early management of powdery mildew is essential to prevent worsening infections. Like with downy mildew, there are a variety of preventative fungicides available for hop powdery mildew.

IPM overview for Hop Powdery Mildew:

  • Whenever possible, plant resistant or early-maturing varieties.
  • Provide the necessary water requirements for plants. Avoid excess.
  • During spring pruning, remove all green tissue.
  • Develop preventative fungicide program to protect growth points.
  • Remove any infected basal growth during the growing season.

We will continue to monitor this and other disease presence in hop yards across the state. If you have a concern about signs or symptoms in your hop yard, please contact me at katie.kreuser@unl.edu. Always remember to scout your hops regularly. Catching the disease early can make all the difference in management.

A note about harvesting & selling your hops

Hop production in Nebraska is very new. Generally hop plants take three years to reach their full yields and ideal alpha and beta acid ranges, given that a weather or other event hasn’t affected the plants during the growing season. One part of education that I, and others at UNL, are trying to pass on to growers is the notion of “If I grow hops, the brewers will come,” is false. The hard truth here is that that statement could not be further from the truth. In most cases, growers must market, grow, and package a quality food product, and convince brewers (of various sizes) that their product is worth purchasing before any income flow. This is not easy, especially when battling weed, pests and diseases already is a full time job before marketing is even considered. It’s not easy because there are significant establishment costs involved followed by potentially a couple of years without revenue from the yields. It’s not easy because as a grower you will most likely give away hops while establishing your buyers, but not without detailed sensory analysis from those on the receiving end. There are many details that should be considered when even beginning to think about growing hops. If you’re considering growing, please take the time to consider these aspects of “growing hops.”

If you are a grower in Nebraska and you have yet to sell your hops, you may have an option through commercial producers in the region. Below are general guidelines that most commercial producers and brewers will require. Remember: hops are a food product.

 

  • Provide you Grower numbers and lot numbers
  • Provide the variety, age of Hop plants, and yields you wish to sell
  • Provide Alpha, Beta, HSI (Hop Storage Index) test results for each variety using the ASBC Hops-6A method from an independent laboratory. (These testing options are offered through Midwest Laboratories in Omaha)
  • Provide all spray records. Follow all governmental regulations and other applicable rules pertaining to the use and application of approved spray and other materials. This includes the use of pesticides, fungicides, and herbicides.
  • At delivery, hops must be within the range of 8.0% to 11.0% moisture and below 85 degrees Fahrenheit.

*If you are interested in selling your hops, you should contact producers as soon as possible so that they can include your hops in their schedule.*

Hops are a viable product for Nebraska. We have rich soils and a terroir unique to our region that helps to contribute to the craft beer that customers demand. I will do my very best to provide you with information to help you create successful business operations to support the growing craft beer market.

Hop Harvest Guide, Pt. 3

In continuation from the post, Hop Harvest Guide, Part 2.

While caring for your hops carefully throughout the growing season is hard work, from the moment the bines are cut down, the real work begins. Hops are harvested when the moisture content is between 75-80%, and the dry matter is around 20-23%. To maintain quality, once harvested, hops are dried to 8-10% moisture for optimum storage.

So your hops are dried. Now what?

Unless you’ve made specific arrangements with a brewer or other user for dry hopping with your hops, you’re going to need to package your hops and store them. Final packaging should involve nitrogen flushing so as to remove any moisture. This is especially essential in the eastern part of the state where humidity levels can be high. This ensures stability in long term storage, preventing the degradation of the acids and oils in the hops. Mylar bag material (a polyester film made from stretched polyethylene terephthalate) is recommended because it keeps out oxygen, humidity and light, and is flexible and light, yet very strong.

Hops can also be compressed into bales using burlap or a polyethylene material. This is recommended if they’re later to be pelletized. Pelletizing is the process of grinding and extruding the hops. Brewers more often than not prefer pellets because of volume in the brewing process (they’re smaller than whole cones), less storage space is needed for pelletized hops, and access to the complexity of flavors in hops is best when using pelleted hops (dry hopping is less efficient and leaves remnants of lupulin behind in the cones).

Whether you are compressing hops into bales or sealing them in mylar bags, research has shown that hops stored at freezing or below temperatures have the optimum storage stability. You can read more about that research from the University of Vermont here.

On your bales or mylar bags, you should have your company name, grower number (free application here), the alpha and beta acid content. Easy access to spray records is a must when speaking with a brewer or broker.

Calculating Harvest Yields

Yield estimation (dried cones) = Wet hops (lbs) x (100 – moisture content of wet hops/100 – moisture content of dried hops)

A note on costs

Competing with the Pacific Northwest for quality and quantity of hops is not a feasible goal at this time. We’re talking about generations of farming hops, on thousands of acres. Their production scale allows them to charge much less for the production of hops. In Nebraska, what we can do well is market local and unique ingredients. We may be growing some of the same varieties as the PNW, but the terrior in our hops gives us the ability to distinguish our products. Our growing environments play on the aromas and lupulin content, making beers quite a bit different. Just take Nebraska Brewing Company’s cardinal pale ale and Meadowlark 150 for example. Both beers follow the same recipe, except that the hops used in the Cardinal Pale ale are from the PNW and the hops in the Meadowlark 150 are grown here in Nebraska. I encourage you to taste the difference for yourself.

Because of the scale, prices are going to be quite a bit less for hops from the PNW. We’re talking as little as $6 or 7 per pound to upwards of $25 or more per pound for proprietary varieties. Price points vary based on the process and volume sold.  The more they’re processed, the higher the price. Hops may be sold in the range of $12-16 per pound depending on variety, with that price increasing if buying in small quantities. The advantage is there are unique, LOCAL qualities that can’t be purchased from the PNW, or anywhere else for that matter. Make that a selling point.

Harvest Demonstration Follow Up

Thanks to everyone who attended the harvest demonstration last Friday. We owe a big thanks to Ryan and Michelle Heine of 6th Meridian Hops for sharing about their experiences in growing hops over the last few years. Taylor Ann Washburn, a field representative for Midwest Labs, attended and shared information about testing options for hops. For more information or how to submit samples, contact Rob Ferris of Midwest Labs, at 402-829-9871.

From the Handout:

Reproductive Growing Season:

  • Mid to late June: burr formation
  • Mid to late July: Burrs to cones
  • Mid-August to September: Cones ripen and moisture content begins to fall; Harvest ideal between 72-78% (discoloration of cones begins below 72% moisture)

Preparing for harvest:

  1. Cones should be light green in color, and bracts should be slightly open.
  2. Bracts at the base of the cone should begin to brown.
  3. Cones should feel papery, and sticky when rolled between fingers.
  4. Hops should have a fresh aroma, not grassy or other off flavors.
  5. Lupulin should be dark yellow-orange in color, and present on the base of bracts.
  6. Calculating cone dry matter percentage.

AND/OR

  1. Lab testing. (The only way to identify exact moisture and acid content.)

Pest Control at harvest:

  1. Continue scouting for pests and diseases throughout harvest.
  2. Be aware of pre harvest intervals (PHI) for any applications.
  3. Continue control of pests on late maturing varieties, while harvesting earlier varieties (minding the PHI).
  4. Be specifically aware of aphids, spider mites, alternaria cone disorder, downy mildew. Each of these pests and diseases have potential to lower yield.
  5. Weed management is a LOW priority during harvest.

Harvest and Post-Harvest Processes:

  • Harvest – removing the flowers, leaves and stems from the bine
  • Separation – sorting cones from leaves and stems
  • Oasting – drying the cones to appropriate moisture content
  • Analysis – chemical assays for acids and oil content; USDA physical quality analysis

Harvesting:

Hand picking

  • Labor intensive (~750 hours/acre)
  • Separation step not needed
  • Benefits:
    • May be able to leave bine up post-harvest to allow more starch and sugar to build up in the root stock
    • Less cone damage and lupulin loss

Mechanical

  • WOLF, Hopster, etc
  • Combines stationary pickers and sorters
  • Cost range: $5,000 to $90,000
  • Range: 1-20 acre

Small scale options from the University of Vermont:

Hop Harvest Guide, Part 2

In continuation from the previous post, I’m picking up with Hop Harvest Guide, part 2. From the previous post, you should have determined the percent dry weight of your hops, and have harvested or set a harvest date. The next step in post-harvest processing is drying your hops. **A side note here, by now you should have arranged the end user of your hops. If you are a new grower, and have not had any conversations with brewers yet, I would suggest drying and vacuum sealing your hops, and giving them to a brewer in exchange for sensory and quality feedback.** Today, I’ll be covering hop quality desired from the drying process, and methods for drying your hops.

Why are drying cones a necessary part of the post-harvest process? The moment hops are separated from the bine, the clock begins ticking before the compounds begin to break down and oxidize. Summer heat and humidity increase oxidation and chances of mold and mildew developing on freshly harvested hops, which may contain up to 80% moisture. You have roughly 45 minutes to begin drying your hops or to bring them to a processor before they begin to break down.

Hops may be incorporated into the brewing process in several forms. Wet or fresh-hopped beers (harvest ales) utilize hops directly from the bine, and generally bring out the most aromas from the hops. Because of the proximity of growers to brewers, most hops are dried to preserve the aromas and acid content present in the cones. From drying, they can be added to brewing recipes, or may be further processed into products such as pellets or hop extract.

Drying

When drying your hops, you should 1) make sure the temperature is regulated so that hops are not over dried or cooked, 2) ensure that water is removed from the cones as fast as possible, 3) the depth of the kiln is reflected by the hop bed weight, and 4) that the harvested hops do not have any surface moisture present (i.e. rain or dew). Do NOT expose your hops to prolonged high temperatures or allow condensation to form on the top layer. These factors will result in harvest loss.

There are two methods commonly used for drying hops, forced-air and modified air flow and temperature system (MAT). The forced-air system maintains a constant air temperature between 100 and 120 °F. A MAT system begins drying with the temperature (around 140 °F) and air speed higher at the beginning of the drying period then reducing both throughout the process (100 and 120 °F). The essential oils in the hops will begin to break down around 130 °F making it extremely important to reduce the temperature throughout the process. If drying at a constant temperature between 100 and 120 °F, drying time will take ~25% more time.

If you are using a kiln, the temperature should be between 100 and 150 °F, and air speed should be between 0.98 and 1.47 ft/s (0.30 to 0.45 m/s) and no higher than 1.65 ft/s. Temperatures are important in relation to the airspeed. When excessive airspeeds are reached, it will cause blow holes in the hops drying. If the temperature is too high and the airspeed is too low, water condensation will settle on the top layer of hops, which is also sometimes referred to as stewing.

The ideal temperature and airspeed ratios:

  • 144 degrees F, 0.30 to 0.35 m/s (1.0 to 1.1 ft/s)
  • 153 degrees F, 0.40 to 0.45 m/s (1.31 to 1.48 ft/s)

The next consideration one must take when drying hops is the moisture content of the fresh air and waste air in order to avoid condensation formation. Measure the following, and maintain lower kilning temperatures:

  • Waste air humidity: it must not exceed 90%
  • Waste air temperature: At 149 °F, exhaust air should reach 36 °F shortly; at 153 °F, exhaust air should reach 86 °F shortly.

When higher temperatures are used, water migrates more quickly from the strig to the bracteoles, raising humidity levels in the drier. A lower airspeed causes the air to become saturated with water before reaching the upper layers of the bed of cones. As the hops dry, the air cools and reduces the amount of water being absorbed by the drier’s air, creating a dense hop bed and reducing air speed and hop quality.

The table below will give you an idea of the weights of pre and post-dried hops.

Weight of Hop Cones
Weight of hops/100 ft2 Bluk density (lb/ft3)
Green Dry Green Dry
24 inch loading depth 930 250
36 inch loading depth 1395 380 4.65 1.25
42 inch loading depth 1630 440
Adapted from Branton, C.I. 1950. A Hop Drier for Oregon Farms. Ag. Expt. Station Bull. 474.

Assessing Hop Quality

**As we have seen over the last few weeks, the temperatures in Nebraska vary wildly. Keep records of drying times and temperatures, but do not assume from year to year that these will be the same.**

Upon drying completion, hop quality is of utmost importance, and is resembled in the following characteristics of the cones:

  • Aroma and acid content: specific to each variety; aroma being a subjective evaluation by brewers.
  • Color: light, bright green; colorless indicates to high of a temperature when drying or late harvest; tan or brown may indicate cones sat too long before drying or the air speed of the drier was too slow.
  • Moisture content: post drying, cones should contain 8-10% moisture.
  • Cone intact: shatter is an indication of over drying