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A New Tool for Understanding and Describing Hop Flavors

The Hop Aroma Standards Kit is a convenient tool for training in the fundamental lexicon of hop aroma and flavor. It can be used by anyone, from seasoned sensory professionals training dozens of brewers, to a small tap-room manager, working to train front of house staff in how to understand the beer they are selling to customers.

The Barth-Haas Group is a large organization full of professionals with a deep understanding of hops, how they smell and taste, and what to do with them. However, with the increasing popularity of American-style India Pale Ales and aroma hops around the world, our teams realized that while we were speaking the same language we still had difficulties speaking the language of hops. Because of this, we developed a unified lexicon: a standard list of attributes with a broad set of examples to accurately describe the character of the 270+ hops grown and used around the world (link).

Even then, because flavor is subjective, and personal histories and cultures are diverse and unique, it was still a challenge to ensure that all of our sensory judges were applying attribute labels consistently. Whether in the US or Germany, the meaning of ‘Floral’ or ‘Citrus’ has to be used in the same way to describe a popular hop like Citra. Because of this, we decided to develop a tool, something tangible to align our European and American panels. That’s why we developed the Hop Aroma Standards Kit.

This kit provides us with a convenient, consistent set of non-perishable standards to use in sensory training. It allows us to easily train large groups of people in multiple locations with little preparation time. In the Barth-Haas Group, in order to train our panels of experts, we apply many different approaches to sensory training on hop flavors including using fresh fruits, vegetables, herbs, spices, botanicals – and of course hops, hop teas, and hoppy beers. We use these techniques as a core part of our sensory training to teach hop flavor. However, Freshness, variety, and availability are always a challenge when it comes to sourcing whole-food standards around the world, especially for large scale training sessions. The Hop Aroma Standards Kit helps us overcome these issues.

Tell me a little about how the Hop Aroma Standards are made

Before making the standards ourselves, we initially looked for products in the market that could be applied as flavor standards for the Barth-Haas sensory language. Our sensory language focuses on positive flavors of hops, however most of the flavor standards sold in the beer industry are focused on negative flavors, off-flavors, and single compounds. After working with multiple suppliers and products, we could not find what we were looking to do. Because of this it became obvious that we would need to create our own hop aroma standards to support our language. After identifying important hop odorant compounds for each flavor category, we then formulated specific blends of hop compounds to match the 12 flavor categories of our sensory language. We spent a lot of time developing the chemical formulations of these aromas. In addition, we hosted repeated sensory panels to test the intensity and quality of each aroma category to ensure they are discernable and of similar intensity.

The most interesting part of the hop aroma standards is that they are made from compounds that have been identified in hops and in hop oil. For example, our Citrus standard aroma has compounds that are well known to exist in hops like linalool and limonene that smell like orange and citrus-like aromas. They are compounds that are native to both hops and citrus fruits. Another example, our Berry and Currant standard aroma has compounds like 4-mercapto-4-methylpentant-2-one (4-MMP) and beta-ionone that are also found in hops that smell like black currant or berries, respectively. This means we are better able to capture a true-to-hops character, without the potential off notes that come with broad extracts and synthetics.

Tell me a bit about the Barth-Haas sensory program and the background on the Barth-Haas sensory language

The Barth-Haas sensory programs operate in tandem between our German and American offices. The German panels are led by Dr. Christina Schönberger and I lead the panels in America. We utilized these panels routinely – multiple times per week – to perform in depth sensory analysis of hops and hoppy beers, focusing on the flavor and quality. We put special focus on these panels in order to better understand hop flavor and how that flavor is imparted on beer. It is from these panels that Barth-Haas compiled the three volume Hop Aroma Compendium, which includes the data on 100+ and is the most extensive sensory resource on hop varietal flavors ever published.

It is also through these panels that three years ago we developed the Barth-Haas sensory language, which was carefully crafted as a tool to describe the nuances of hop flavor.

We use this language in our hop breeding programs and research breweries worldwide to develop new hop varieties, new hop products, and do quality testing. The language is composed of 12 flavor categories (Floral, Citrus, Green Fruit, Sweet Fruit, Berry & Currant, Cream Caramel, Woody Aromatic, Menthol, Herbal, Spicy, Green-Grassy, and Vegetal), which are further broken down into dozens of common sub-flavor terms. The 12 flavor categories can be used to describe the flavor of any hoppy beer and can be used to profile the aroma of the 200+ hop varieties that exist worldwide.

Our goal with the Barth-Haas sensory language is to create a uniform way to speak about hop flavor. There are virtually infinite ways to describe the same hop flavor – none of which are inherently wrong or right – because every person is impacted by their culture, history and personal relationship with food. Because of this, flavor descriptions are inherently subjective. The goal of the Barth-Haas language is to provide a common framework to describe hop flavor and speak the same language. We encourage others in the brewing industry to use the Barth-Haas sensory language to collectively better the understanding of hop flavor.

How do you use the Hop Aroma Standards Kit?

The Hop Aroma Standards Kit is designed to be only used for smelling (orthonasal olfaction). To use the kit you simply take an aroma vial, unscrew the cap, and smell the aroma that diffuses from the aroma vial. Then replace the cap on the aroma vial and return the vial to its position in the Kit. The 12 vial colors correspond to the 12 aroma categories.

The goal of the kit is for it to be a convenient tool for anyone to learn how to profile hop flavor using the 12 flavor categories of the Barth-Haas sensory language. The kit can be used to improve the individual judge’s ability to differentiate between and identify the individual hop flavors and to be able to further associate them with specific flavor terms – ‘grapefruit’ and ‘lemongrass’ rather than ‘citrus’, ‘cedar’ rather than just ‘wood’. In addition, the kit creates a common vocabulary amongst a panel of judges, or multiple panels of judges in different locations. All of this combines to increase the accuracy and power of any given evaluation.

Ultimately, we hope the Hop Aroma Standards Kit allows you to better familiarize yourself with varietal hop flavors. On the John I Haas website, we provide sensory data and flavor descriptions for all the major hop varieties. You can use the Hop Aroma Standards Kit and our sensory resources to better understand the flavor of hops and hop products. Hopefully, this means that anyone can learn to make better beer and to better enjoy better beer.

We recommend placing the Hop Aroma Standards Kit in your sensory booths, sensory room, or space designated for beer quality evaluations. In this area it can be used as a warm-up before sensory evaluation of hops and hoppy beers.

What’s been the response from brewers when you show them these standards?

I see people get really excited when we use the Hop Aroma Standards Kit in demonstrations and show them to customers; there’s a definite “wow!” factor. It seems like this is something people have been looking for. Although we initially created the standards strictly for internal purposes to train our Barth-Haas sensory panels, over time we realized that throughout the brewing industry there is a keen interest in sensory training tools, too.

Two of the most frequently asked questions that I receive as a sensory manager from our brewers: “What is your sensory language to describe hops?” and “How do you train on specific hop flavors?” Because of how common these questions are, I believe there is a need in the brewing industry for more and better sensory training tools and information about hop flavor.

In the United States we have 7,000 breweries and counting. The vast majority of them are small craft breweries and brewpubs—not exactly the type of business with an unlimited budget that can be dedicated to an in-house sensory panel. Many of these breweries sell hop-forward beers, where hops provide the critical flavors of Sweet Fruit, Citrus, and Cream in their biggest volume beers. Our goal with the Hop Aroma Standards Kit and the Barth-Haas Sensory Language is to provide the brewing industry with tools to better understand hop flavor.


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