Demystifying the Art of Hop Selection: An Insider's Perspective from Yakima
Introduction
Every September for the past two years, I've found myself in Yakima, Washington—a name synonymous with hops in the U.S. During this time, I've been inundated with queries from fellow brewers, friends, and old coworkers, asking, "What exactly are you doing there?" The answer? Diving deep into the highly specialized and nuanced process of hop selection.
While each hop supplier or grower has their own unique way of conducting hop selection, the general premise remains the same. Today, let's unravel the intricacies of what brewers look for, the factors involved in their decisions, and much more.
Factors Beyond Sensory Profiling
Selecting hops involves much more than just taking a whiff and checking off boxes in a sensory chart. Here's a quick rundown of some of the other factors that influence the decision:
Availability and Blending
You may stumble upon the perfect hop lot, but if the availability is limited, it's back to the drawing board—or you'll have to consider blending different lots to achieve the desired profile.
Hop Storage Index (HSI)
This measures how well a hop retains its alpha acids over time. A low HSI means the hops will age better, crucial for breweries that aren’t using their hops immediately.
Oil, Alpha, and Beta Contents
The concentrations of essential oils, alpha acids for bitterness, and beta acids for aroma and stability are critical for flavor, aroma, and the beer's shelf life.
The Hop Grower and Farm
Where the hops come from can say a lot about what they bring to your brew, from soil chemistry to cultivation methods. The terroir (geography) and personal ties to the grower/farm can also sway the selection decision.
Pick Window
Increasingly, more knowledgeable brewers pay keen attention to the time of harvest, known as the "pick window," to optimize aroma and other characteristics.
The Harvest Window: A Pivotal Factor in Hop Sensory Profile
In the realm of hop selection, the harvest window stands out as an often-underestimated variable that can substantially impact the final sensory characteristics of a brew. While hop growers and breweries are becoming increasingly savvy about this factor, it still deserves a spotlight for its critical role in influencing aroma, flavor, and even stability of the beer.
What is the Harvest Window?
The harvest window refers to the specific timeframe during which hops are harvested. It's not a one-size-fits-all calendar mark, but rather a spectrum that varies depending on hop variety, location, and environmental conditions of the growing season. During this window, the hops reach their peak in terms of desired alpha and beta acids, essential oils, and other compounds that contribute to a beer's aroma and flavor.
The Impact on Sensory Characteristics
Aroma and Flavor Development
Hop cones develop their aromatic and flavor compounds over time. Harvesting too early may result in a grassy, unripe aroma, lacking in complexity. On the flip side, a late harvest can bring forth more earthy, herbal, or even oniony attributes—flavors not always desired in specific beer styles. Striking that perfect balance is crucial for achieving the intended sensory profile.
Alpha and Beta Acid Content
The alpha acids, responsible for bitterness, and the beta acids, contributing to aroma and stability, also fluctuate during the growing cycle. An early harvest usually yields lower alpha and beta acids, whereas a late harvest can ramp these numbers up but potentially at the cost of diminishing aroma compounds.
Essential Oils
These are the magic behind many of the complex aromas we associate with craft beers. Compounds like myrcene, linalool, and geraniol are affected by the hop's maturation level at the time of harvest. Depending on the desired beer profile, brewers may opt for an earlier or later harvest to tweak the oil composition in their favor.
Practical Considerations for Brewers
Sensory Testing
Experienced brewers and hop growers often engage in field sampling leading up to the harvest. This hands-on approach allows for a more targeted selection process, ensuring that the hops are harvested at their sensory peak for the intended brew.
Contracting Specifics
Some brewers go as far as specifying desired harvest windows in their hop contracts, ensuring that the sensory characteristics align precisely with their brewing needs.
The Layer of Complexity
The harvest window adds a layer of complexity to an already intricate process of hop selection. But it’s a layer worth diving into, given its substantial impact on a brew’s sensory profile. By understanding and harnessing the power of the harvest window, brewers not only up their hop game but also inch closer to that ever-elusive goal—crafting the perfect brew.
Sensory Science
Sensory science in the context of brewing serves as a robust language with established standards, allowing for a more structured and effective dialogue among brewers, suppliers, and consumers. This specialized field employs a lexicon that goes beyond basic descriptors like "bitter" or "fruity," incorporating a comprehensive set of terms that capture the multi-dimensional aspects of hops, malt, and the beer itself. Standardized sensory panels, often facilitated by certified tasters, employ these terminologies to evaluate aroma, flavor, mouthfeel, and other tactile experiences. The process is underpinned by meticulous methodologies—ranging from the Double Triangle Test for similarity checks to the Quantitative Descriptive Analysis for in-depth profiling. This standardization not only brings a uniformity to the sensory evaluation but also ensures that regardless of who is speaking—whether an artisanal brewmaster or an industrial supplier—the language and its implications are universally understood.
Let's take the example of the sensory term "tropical fruit" often used to describe certain hop varieties like Azacca. In a standardized sensory panel, the term "tropical fruit" is not thrown around loosely. It is carefully defined, often with sub-categories specifying whether the panelist detects notes of "mango," "papaya," or perhaps "passionfruit." The evaluation doesn't stop there. Standardized scales, often numerical, are used to indicate the intensity of this characteristic (for example, a scale from 1-10). This rigorous approach to sensory evaluation ensures consistent language and understanding among brewers and suppliers alike.
The Selection Process: An Insider's View
Brewers participating in selection usually come in with a well-defined idea of what they're looking for. They engage with cores pulled from different lots, engage in the ritual of "rub and sniff," and over a span of a few hours, narrow down their choices.
Mosaic selection is one I dearly love. Not only does Mosaic vary wildly between farms and terroirs, but brewers have very specific ideas of what their Mosaic needs to be. Some of the sensory characteristics don’t even exist in a formal sensory chart (ie. The word “purple” to describe Mosaic has come up more than once).
Post-Processing: Pelleting and Advanced Lupulin Processing
In theory, the hop's profile shouldn't change much through pelleting or advanced lupulin processing. However, some brewers find noticeable differences post-processing, suggesting that some variables still elude our understanding.
The debate over the merits of selecting hops in their un-pelletized, whole cone form is a nuanced one that each brewer must consider based on their unique needs and priorities. Whole cone hops offer the advantage of a more unadulterated sensory experience during selection, allowing brewers to evaluate the flower in its natural state. This arguably offers a purer gauge of aroma, texture, and oil content, elements that may be somewhat altered or compromised during the pelleting process.
However, pelletized hops offer the chance for real-world testing directly in your brew. You can easily integrate a small quantity into a test batch to understand how they will impact your final product. This form of 'pilot brewing' allows you to make informed decisions about larger-scale brewing, giving you a practical sense of the hop's aroma, flavor, and bitterness contributions without having to commit to a larger quantity.
Final Thoughts
Hop selection is both an art and a science, steeped in tradition but constantly evolving with technology and knowledge. The annual pilgrimage to hop meccas like Yakima isn't just a buying trip; it's an exercise in refining one’s palate, understanding supply chains, and ultimately, affecting the soul of the brew you're crafting.