Table of Contents
WHAT ARE HOPS?
HISTORY OF HOPS
GROWING CLIMATE
HOP VARIETIES
GLOBAL PRODUCTION
HOPS: A KEY INGREDIENT TO CRAFT BREWING
HOP DELIVERY METHODS
HOP OIL
WATER-SOLUBLE HOPS: THE FUTURE OF HOPS IN BEER
Bell’s Hopslam. Dogfish Head. Discord. Latitude 48. Ruination. What do these words have in common? They are all the names of craft beers with a taste and aroma best described as “hoppy.” What does a hoppy beer taste like? That depends on the type of hops used, where the hops are grown, how much of the hops are integrated into the flavor profile, and how the beer is brewed.
Here, we’ll dive more into the world of hops and cover all aspects of this plant!
WHAT ARE HOPS?
Hops are the dried, cone-shaped female flower of a climbing perennial bine called Humulus lupulus that are integral to beer brewing because they impart bitterness and flavor as well as contribute to stability and shelf life. A bine is a climbing plant which climbs by its shoots; a vine is a climbing plant which climbs using suckers or tendrils. Hop plants are dioecious, meaning the male and females flower on separate bines.
There are four major components of a hop cone: the Strig, the Bracteole, the Bract, and the Lupulin glands.
The strig is the base of the flower where the hop connects to the bine. This is where most of the tannins are found. Tannins give the hop medicinal properties via polyphenols, which are the major contributor to the harshness or smoothness of a particular hop’s bitterness.
The bract is the exterior part of the hop comprised of leaf-like structures. The bract also contains polyphenols.
The bracteole are located in the hop cone’s interior that give the cone its structure.
Within the bracteole reside the Lupulin glands, which hold the resins and essential oils. When you break open a hop, the glands are yellow and resemble a pollen pouch; once the glands are exposed, the aroma of hops can be quickly detected. The Alpha acids, Beta acids, and essentials oils produced by the lupulin glands have the greatest impact on the beer’s taste and aroma, making them an important part of the brewing process.
Alpha acids give beer its unique bitter taste and suppress bacterial growth.
Beta acids contribute to a beer’s shelf life as well as the yeast’s ability to grow.
Essential oils or terpenes like Humulene, Myrcene, and Caryophyllene add aroma and flavor. Typically, the notes they impart are described as “citrusy,” “earthy,” “spicy,” “piney,” or “herbaceous.”
HISTORY OF HOPS
Today, hop-forward beers like IPAs and Pale Ales are featured prominently on store shelves and in tap rooms. The practice of integrating hops into the brewing process goes back hundreds of years. Prior to the 11th century, brewers used a mixture of herbs, called gruit, to flavor their beer. Between the 11th and 16th centuries, brewers started replacing the gruit with hops because hops were cheaper and more effective at preserving beer.
In 1512, Duke Wilhelm IV of Bavaria introduced Reinheitsgebot, the beer purity law, which enforced the restriction of any ingredient outside of hops, barley, water and later, yeast, in every stein. This recipe served Bavaria very well for 500 years and Germany for the last 100. In the late 1700s, hops became even more widely used as they were added to help maintain the quality of the beer, given some of the hop’s compounds’ antimicrobial properties; the iso-α-acids specifically act against bacteria. Hops were utilized for that purpose in the beer that was transported by ship from England to the British colonies in India, which is how IPA, India Pale Ale, got its name.
Brewers utilize hops to develop complex, unique flavor profiles to meet consumer demands for craft brews. Brewers have options as to how and when to incorporate hops to the brewing process. Each option affects bitterness, aromas and flavors of the finished brew as well as time, machinery, and overhead costs of production. While the integration of hops into the brewing process presents challenges for brewers, new technology such as emulsion technology offers innovative solutions that may become the future of brewing with hops.
GROWING CLIMATE
Hops grow best in temperate climates where it is warm during the summer and cold during the winter when the vine goes into dormancy and all of the plant’s energy goes to its roots. The plant thrives in the climate between the 35th and 55th parallels on either side of the equator.
It typically takes three to four years for a plant to mature. Because hops can grow as tall as 20 to 25 feet, they need to be supported by trellises. When the bines on the hop plant begin to emerge, they grow upwards of six inches. At this point, they are trained to grow vertically, clockwise, around the trellis.
HOP VARIETIES
While there is only one hop species, Humulus lupulus, there are several varieties, also known as cultivars, that brewers choose for their different properties.
Aroma Descriptors for Hop Cultivars
| Hop Cultivar | Aroma |
| Brewer’s Gold | Black currant, fruity, spicy |
| Cascade | Flowery, citrus, grapefruit |
| Chinook | Spicy, piney, grapefruit |
| Willamette | Mild, slightly spicy, black currant, herbal |
| Fuggle | Delicate, minty, grassy, slightly floral |
| Hallertau | Mild, pleasant |
Hop varieties are classified into three categories: Bittering hops, Aroma hops, and Dual-purpose hops. With their high Alpha acid levels, bittering hops lend bitter flavor to beer. With low to medium Alpha acid levels, aroma hops mostly contribute to the beer’s smell. Dual-purpose hops offer aromatic properties as well as medium levels of alpha acids.
GLOBAL PRODUCTION
The United States and Germany are the largest producers of hops across the globe. The main producers of hops in the US are Washington, Oregon and Idaho; in Europe, Germany and Belgium; and in the southern hemisphere, New Zealand. In 2019 in the US, 113 million pounds of hops were harvested, an increase of almost 5% over 2018. For hops grown in the Pacific Northwest, Washington production represents 73.2% of total production, followed by Idaho with 15.2% and Oregon with 11.6%.
HOPS: A KEY INGREDIENT TO CRAFT BREWING
Hops are an integral part of the current craft brewing experience because of the unique flavors and aromas they impart on the beer as well as the role they play in preservation of the beer and its shelf life. Hops make beer more complex; they add layers of flavor and bitterness, contributing to the beer’s weight and mouth feel on the palate.
Brewers use hops for three different reasons:
- To add bitterness to the brew using bittering hops with their high Alpha acid levels
- For adding aroma and flavor using aroma hops with their low to medium Alpha acid levels
- To create haze, the cloudy appearance of the liquid that the hop particles create.
These three elements of hops are carefully adjusted and specified to serve the ever-evolving market and is evident in existing hop forward beer profiles.
Dry & Earthy: English Pale Ale, English India Pale Ale, Belgian IPA, Ordinary Bitter
Fruit & Full Malt Body: California Common, American Amber Ale, American Imperial Amber Ale
Bold, Herbaceous & Citrus: American Pale Ale, American Fresh Hop Ale, American India Pale Ale, American Imperial IPA
HOP DELIVERY METHODS
There are several ways brewers can add hops to their brews. Each method brings with them a unique set of challenges.
Dry hopping is the process of steeping or soaking the hops in the wort during fermentation or conditioning which releases the hop cones’ essential oils. These oils add aroma and flavor to the beer without adding bitterness. When dry hopping, a brewer can choose to either use dried whole female flowers (cones) or hop pellets, which are produced by grinding up dried hop cones and pressing them into pellets. There are benefits and challenges to using these two different dry hop forms.
Using whole hops imparts a very fresh aroma and flavor, and they are easier to remove from the brew, although they take up a considerable amount of space in the fermenter and absorb a fair amount of beer. Using hop pellets tends to create a more stable end product, with less risk of oxidation. While there are advantages to dry hop pellets, it comes at the loss of essential oils, which are integral to the sensory effect of the resulting brew.
Adding dry hops to a brew has obvious benefits such as creating complex, unique flavor profiles; adding varying levels of bitterness; and extending shelf life. Currently some brewers choose not to filter out all of the hop particles to create haze or cloudiness in the final product.
There are also unavoidable downsides to this method of hop integration.
Hop creep is best described as continued fermentation in the keg or bottle after packaging. Hop creep is caused by the trace amounts of residual enzymes in the hops converting starch into sugar. In the presence of yeast, the sugars will ferment and will produce Diacetyl, an organic compound commonly used in the flavor industry for its buttery quality. Diacetyl is what will make a beer taste buttery.
Hop burn is the process of over-hopping the brew to compensate for the fading of the hop aroma over time.
Oxidation is the exposure of the hops to oxygen which can result in off flavors.
Yield loss is the result of the dried hops rehydrating upon being added to the brew. The dried plant matter absorbs the wort, which can result in a 5% or higher loss of the entire batch, even with the use of centrifuges and filter presses. If the brewer is producing a double, triple or quad-hopped beer, which are higher in alcohol by volume, they can lose upwards of 12 to 15% of the entire batch.
Brewers can create a hazy or cloudy appearance in their beer by not filtering out all of the hop particles. The downside to this is that it can shorten the beer’s shelf life, which can lead to more buyback after the “best before” date.
HOP OIL
Hop oil is the resinous, pure essential oil extracted from fresh hops. Brewers typically add hop oil in the boiling phase to provide flavor and aroma. There are two methods of extracting the oil from the cones, leaving the biomass: steam-distilling and liquid CO2 extraction. Because hop oil has a longer shelf life than fresh hops, a brewer can purchase it and store it until they are ready to use it. Utilizing hop oil has trended in popularity among brewers to preserve shelf space and mitigate issues associated with dry hopping, although this newer method of incorporating hops comes with its own set of challenges.
The first significant challenge brewers face using hop oil is that oil is the oil is not water soluble. Because of this, 190 proof spirits such as Everclear need to be used as solubilizers, but those spirits are not always available on the market, and some jurisdictions do not allow for the addition of spirits in beer production.
Another challenge is unwanted separation and stratification that can occur in the finished product. When a brewer adds solubilized hop oil to the boil, which is mostly water, it will result in a visual separation between the two liquids where hop oil rises to the top of the water layer. During the boil, there is heat and agitation, where some of the oil is absorbed into the solution due to fats in the kettle. In this case, the conversion rate of the oil into the water is very low. If the brewer doesn’t keep the tank continually mixing, there will be stratification of the flavor layers. During the time where the tank cools down slightly and the solution is slowly drained from the tank, the hop oil rises to the top of the water solution and is eventually be drained off as waste.
Dosing variance from batch to batch has proven to be an obstacle for brewers using hop oil. Because hop oil is highly concentrated and used at usage rates as low as 2 to 5ml per barrel, accurate dosing is extremely important. Minor variances can have significant impacts on the beer’s sensory profile. The margin for error is small, and working with potent, viscous oil increases the risk of dosing in excess leading to discarded batches.
WATER-SOLUBLE HOPS: THE FUTURE OF HOPS IN BEER
Using its patent-pending water-soluble technology, SōRSE Technology emulsifies hop oil for a simplified one-step integration into the brewing process resulting in better-tasting beer. SōRSE water-soluble hop oil emulsions are customizable in aroma, flavor, and opacity.
Enhanced Aroma and Flavor Profile
24 to 48 hours after the emulsion is added to the brew, there is a continued aromatic flavor bloom that can continue after packaging. Water-soluble emulsions give the brewer the ability to work with their supplier and fine tune the flavor profile using other terpenes and natural ingredients. Water-soluble hop oil emulsion also eliminates the possibility of hop creep and hop burn, both unwanted sensory experiences for the consumer.
Visual Esthetic – Haze
With hop emulsion, brewers can customize the beer’s visual attributes such as a hazy appearance without reducing its shelf life. The primary control point for creating haze is the size of the emulsified oil droplets; the smaller the droplet size, the greater the haze. The stability of the haze emulsion within the beer is 12 months and continues to maintain its integrity.
Versatility
Hop emulsion gives brewers the ability to create multiple uniquely flavored beers from one foundation base. Because the water-soluble oil is added at the end of the brewing process, the batch can be divided and infused with different emulsions formulated for specific sensory attributes.
Consistent, Predictable Dosing
When working with highly concentrated hop forms, dosing is critical to the batch’s sensory profile. Because water-soluble emulsion are homogenous and have a low level of viscosity, the loading level of the hop oil can be adjusted to minimize dosing variance.
Cost, Time, and Labor Savings
The time and labor saved using an emulsion includes sourcing, storing, and preparing the hops for processing as well as time in the kettle, filtration, and cleanup. The “drop and go” emulsion integration process is an efficient end-of-production step. Once the emulsion has been added to the bright tank, carbonation and bottling can begin. Because filtration loss is minimized, the yield per batch increases by 5+%.
Because the emulsion is added post-filtration as opposed to incorporation processes at several and different brewing stages, the time and labor associated with dry hopping is eliminated and the production window is shortened. Increased throughput means a faster turnover of batches and an efficient use of materials.
Sustainability and Environmental Footprint
Sustainability practices are becoming more important to today’s producers and consumers, who are more aware of their environmental footprint. Replacing dry hopping with hop oil emulsion increases the brewer’s sustainability efforts; with the hop oil emulsion utilization rates, a quarter of the hops are needed for the same output. By replacing hop flowers or hop cones with hop oil emulsion, the amount of fuel needed for transport decreases. With a decrease in storage requirements, brewers reduce their energy usage.
As the climate continues to change, some hop varietals are dying. Fractionation of aroma compounds allows the hops farmer to grow heartier varieties, strip away the off-flavors, and deliver rare aromas without the agricultural risk.
The history of hops’ role in the brewing and production of beer is a rich one, going as far back as the 10th century. Today, brewers have fully embraced hops, given the varied flavors and aromas that the cones can impart on a beer, as well as the way it can alter a beer’s appearance, creating cloudiness and haze.
Consumers of craft brews know what attributes they like in their beer—while one person may seek out a Porter for its depth of flavor, richness, and caramel or chocolate notes, another may choose an American Pale Ale for its medium body, its maltiness, and its citrus and floral flavor notes – otherwise known as its “hoppiness.” As craft breweries continue to create uniquely flavored beers utilizing the essential oils in the hop cone, there continue to be hurdles based on the hop delivery method.
SōRSE Technology has designed a novel solution with a seamless, one-step delivery method for hop integration, providing a better-tasting, less labor-intensive craft beer. Designed with brewers and consumers in mind and backed by 200+ years of food and beverage product development experience, SōRSE hop emulsions provide a better hop delivery system for the brewer, and a better-tasting beer for the consumer.
Great beer begins with great ingredients. Book a meeting today to speak with our team about the solutions we offer for beer and other beverages. For your hops, go to the SōRSE.
RESOURCES
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Diane Brown, “A Brief History of Hops and Its Uses,” https://www.canr.msu.edu/uploads/236/71516/ipm_academy_2014_intro_to_hops.pdf.
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