413: Hop Scientists Megan Twomey and Ryan Christian Share the Latest on Virus-Free Hops

At the turn of the 21st century, it wasn’t uncommon for a hop grower focusing on alpha varieties to replant a field every 25 to 50 years. While the plants in the field inevitably contracted viruses, the impact of those viruses on alpha-acid development and overall yield was manageable.

In today’s environment, however—with new varieties bred to be high-performance, high-aroma, well-oiled machines—the same viruses have an outsized effect, and a field’s lifespan may be just a quarter of what it used to be. Yet many growers have been extending the productive lives of those fields by planting virus-free rhizomes and plugs—plants grown from cuttings taken from portions of other hops plants where viruses can’t travel.

In this episode, we talk with scientists and hop breeders Megan Twomey of Latitude 46 and Ryan Christian of Yakima Chief Ranches for perspective on how viruses affect hops, how virus-free plants are produced, how long plants can remain virus-free, and more—and how all of that ultimately affects what’s available to brewers. Through the conversation, they touch on:

• different viruses that affect hops
• how viruses affect lupulin production in modern hop varieties
• viral impact in producing genetically true-to-type but phenotypically out-of-spec hops
• “cleaning up” hops to create virus-free plants
• how and now not to monitor fields for viruses
• field dynamics from new plantings over the first few years
• how viral stress impacts plants and their flavor and aroma expression
• yield benefits from virus-free plantings

And more.

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