Improving Brewing Efficiency with Synergy Pure® Hop Essence

By: Lilibeth Dagulo, Research scientist iii, Synergy Flavors, Inc.

Application of Synergy’s unique horticultural processing capabilities to hops resulted in the creation of new solutions for the brewing industry to improve efficiency, safely and consistently. Hop essence has proven to reduce cost, improve product-loss, and increase flavor/aroma without imparting any added bitterness or impacting stability.

Overview of brewing process and utilization of hop pellets

During the beer brewing process, hops are added to impart bitterness and aroma. There are various forms of hop products that are typically used, including whole cone (fresh or dried), dried pellets (T-90 or T-45), extracts, or oils. Hop pellets, for example, can be utilized during multiple stages of the beer brewing process, depending on the style of beer. In general, there are 3 types of hop additions: kettle-hopping, late-hopping, and dry-hopping. In beers like Pale Ales (PA) and India Pale Ales (IPA), the dry-hopping technique is generally used to increase hop aroma and flavor, which is done by adding the hops post-fermentation on the “cold side” of the brewing process (1). The cost of dry-hopping on an industrial scale can be high and potentially unsustainable due to elevated dry-hopping rates, significant beer loss during the removal of hop material, and the price of aroma hop varieties (2).

What is a hop essence?

Synergy Pure® Essences are produced using a proprietary steam distillation process. This process transforms horticultural items into clean, highly concentrated, water-soluble, natural essences which retain the unique aromatic and flavor profile of the starting raw material. Synergy takes great care in sourcing the highest quality raw materials to ensure our essences profiles are true to nature. To do so requires close working relationships with local, national, and international growers. As no two horticultural items are the same, Synergy’s team of R&D Scientists work tirelessly to optimize processing conditions to ensure the highest quality end product. This is achieved by having a thorough understanding of each raw material and its physicochemical properties, as well as precise control over processing parameters such as distillation time and temperature.

Development work on Synergy Pure® Hop Essence began in early 2015, with commercialization efforts beginning shortly thereafter.  We have worked with about 15+ various hop profiles, including the resinous/herbal/spicy types of Simcoe and Columbus to the citrus/fruity/floral types of Citra and Mosaic. Current internal offerings include Columbus, Centennial, and a unique blend, each with different aromatic profiles and flavor characteristics. We also work with several breweries to convert their own hop pellets into hop essences.

Benefits of using hop essence

Although hop essences can thrive in any beverage application for their clean, naturally captured taste, they also provide a unique proposition to the beer making industry.

Authentic flavor profile

Synergy Pure® Essences are clean, highly concentrated, water-soluble, all-natural essences which retain the unique aromatic and flavor profile of the starting horticultural item. They are the cleanest flavoring and aroma-adding ingredients that can be used since our essences contain no ingredients other than the horticultural items themselves. As such, the authentic flavor profile of any particular hop varietal can be highlighted. Synergy Pure® hop essences contain all of the characteristic hop-derived compounds, including the terpene hydrocarbons myrcene, β-caryophyllene, and α-humulene, which make up about 80% of the total volatiles of hop varieties. They are typically responsible for the resin, pine, herbal, spicy, and woody aromas. Terpenoids, such as linalool and geraniol, are also captured in Synergy Pure® hop essences, and they are highly regarded by brewers for providing fresh, floral, and citrus notes to beer. A variety of sulfur and ester compounds, such as 4-mercapto-4-methylpentan-2-one (4MMP) and isoamyl isobutyrate, can also be found, and provide non-citrus fruity and tropical notes associated with more fruit-forward hop varietals (3).

More efficient extraction of volatile compounds than dry-hopping

Research over the last few years has been done by authors such as Hauser (2) and Brendel (5) to understand some form of extraction efficiency of dry-hopping, that is, the transfer of volatile compounds from hops into beer. They join several other researchers who have found that the extraction rates varied significantly, depending on the chemistry of the compounds. The extraction rates for terpene hydrocarbons, such as myrcene, β-caryophyllene, and α-humulene, only ranged from 0.2 – 2.0% due to their hydrophobic nature. This meant that they preferred to stay with the hop material rather than move into the beer. More hydrophilic compounds, which would readily move into the beer, like the terpenoid linalool, saw extraction rates ranging from 63 – 111%. In a recent trial conducted at Synergy, beer dosed with Synergy Pure® hop essence was compared to beer produced with a model dry-hopping process. Results showed higher concentrations of hop-derived compounds overall in the beer with hop essence, particularly with the terpene hydrocarbons. This suggested an improved extraction of volatile compounds with Synergy’s proprietary steam distillation process.

Increased yield due to reduction in beer absorption. More sustainable process

Dry-hopping is commonly known to cause significant yield losses as hops or hop pellets can absorb several times their own weight. Published values regarding loss and absorption seem to be scarce, but Janish had reported on work that looked at beer losses at different dry-hopping rates. It was found that absorption of beer from hops ranged from less than 2% at 0.65 lb/bbl to 6% at 2.59 lb/bbl and 14% at 5.17 lb/bbl (4). This beer is typically lost when the hops are removed prior to bottling. Poor yields are particularly prevalent in smaller breweries which do not possess centrifugal equipment to minimize beer loss. Full or partial replacement of hops with hop essence is a solution to eliminate or minimize yield losses associated with dry-hopping whilst maintaining overall flavor and aroma. After dry-hopping is complete and beer has been decanted, brewers are also typically left with the conical sections of tanks full of spent hops. In some instances, brewers are required to manually remove this material before tanks can be cleaned. Utilization of hop essences can also reduce or eliminate this residual hop material. With the increased yield and reduced waste, hop essence has the potential to save cost.

No bitterness and light stable

Other hop products on the market include hop extracts and hop oils. Hop extracts are typically produced using supercritical CO₂ extraction. They are quite expensive and difficult to work with as they are extremely viscous. Additionally, they often contribute bitterness to the beer, due to the presence of alpha and beta acids, which is a limiting factor in their use. Depending on where the extract is used, isomerization of the acids to their iso-forms can occur (1). In addition to providing bitterness, iso-alpha acids can also impact light stability in beer. They are known to react with sulfur containing proteins in beer in the presence of UV light to form 3-methyl-2-butene-1-thiol (3-MBT), which is responsible for the skunk or “light struck” off-aroma (6). Hop essences, on the other hand, are easy to handle,

 are light stable, and do not contribute any bitterness to the beer as they do not contain any alpha and beta acids or their iso-forms. This has been confirmed through testing by HPLC methods according to the American Society of Brewing Chemists (ASBC). Much like hop extracts, hop oils are also very expensive and difficult to work with due to their poor solubility. They need to be made into an emulsion or mixed with a solvent like ethanol to improve solubility (1). Hop essences, on the other hand, are significantly more cost effective and have excellent solubility in beer.

Ease of use and time savings (i.e. liquid injection vs storage on dry-hopping)

Typically, for dry-hopping, hops are added to beer post-fermentation followed by refrigerated storage for approximately 2 weeks. This lengthy period of time is required to extract the flavor components from the hops into the beer (1). One benefit associated with full replacement of hops with hop essence is a reduction in cycle time. Hop essence can be added to beer post-fermentation and immediately bottled, eliminating the need for 2 weeks of refrigerated storage. 

Safety

Addition of hop pellets during dry-hopping is often regarded as a dangerous process, particularly in smaller breweries which are less automated. Hops are typically added through small ports in the upper extremities of vessels. To do so requires brewers to repeatedly climb ladders and manually dose hops. Doing so creates a high risk for injury to brewers, e.g., slipping whilst climbing ladders, pulling muscles whilst lifting bags of hops overhead, etc. Hop essences, on the other hand, can be added via automated dosing pumps from the ground floor, thus eliminating these safety concerns.

Customization and Clean Label

There is also increased customization ability with clean label connotations from using hop essence. It allows brewers to create multiple different products from a standard base, i.e., brewers can ‘mix and match’ hop essences to create desired flavor profiles. Since hops and water are already present in the beer, the beer maker can play around with different varietals at optimal levels and not have any concerns on how it will affect their label. 

Beverage Solution Beyond Beer

Synergy Pure® hop essences are best utilized during the brewing process for beer. However, there are also a range of other applications that hop essences can thrive in if hop aroma and flavor are desired.

Non-alcoholic (NA) beer

For example, sales of non-alcoholic (NA) beer have increased significantly over the past few years. There are several physical and biological methods of removing alcohol from beer, including thermal dealcoholization and stopped fermentation by removing or inactivating yeast before reaching a specified alcohol content. Both types of methods impact the final aroma of NA beer in different ways. The odor of NA beer produced by thermal dealcoholization, for instance, has been described to be unpleasant and atypical due to the removal of desired aroma compounds during heating. NA beer produced by stopped fermentation is also lacking in typical fruity notes produced during normal fermentation, resulting in a sweeter aroma that is more wort-like (5,6). Utilizing hop essence in this application is one strategy to mask or add aroma to NA beer.

Cross beverage category appeal

Beyond beer, Synergy Pure® hop essences can be used to bring authentic hop flavor to all sorts of beverages, from sparkling, functional, or indulgent. Trending applications also include other low-alcohol and low-calorie drinks such as hard seltzers, water, and tea.

References:
     1) Wolfe, P. (2012) A Study of Factors Affecting the Extraction of Flavor When Dry Hopping Beer, Thesis, Oregon State University
     2) Hauser, D., Lafontaine, S., & Shellhammer, T. (2019) Extraction Efficiency of Dry-Hopping. Journal of the American Society of Brewing Chemists, 77(3), 188-198. Doi:10.1080/03610470.2019.1617622
     3) Rettberg, N., Biendl, M., and Garbe L. (2018) Hop Aroma and Hoppy Beer Flavor: Chemical Backgrounds and Analytical Tools – A Review. Journal of the American Society of Brewing Chemists, 76(1), 1-20. Doi:10.1080/03610470.2017.1402574
     4) Janish, S. The New IPA – A Scientific Guide to Hop Aroma and Flavor. Chapter 7: Dry Hopping, Page 114. Monee, IL; ScottJanish.com; 2019
     5) Brendel, S., Hofmann, T., and Granvogl, M. (2020) Dry-Hopping to Modify the Aroma of Alcohol-Free Beer on a Molecular Level – Loss and Transfer of Odor-Active Compounds. Journal of Agricultural and Food Chemistry, 68, 8602-8612 https://dx.doi.org/10.1021/acs.jafc.0c01907
     6) Lafontaine, S., Senn, K., Dennenlör, J., Schubert, C., Knoke, L., Maxminer, J., Cantu, A., Rettberg, N., and Heymann, H. (2020) Characterizing Volatile and Nonvolatile Factors Influencing Flavor and American Consumer Preference Toward Nonalcoholic Beer. ACS Omega, 5, 23308-23321 https://dx.doi.org/10.1021/acsomega.0c03168

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