Vertical integration is the optimal way to deliver top quality services and products to growers and customers. In 1997, Yakima Chief, Inc.’s 100% grower-ownership (now Yakima Chief – Hopunion, YCH) made the decision to build a hop extract facility in Sunnyside, WA. This decision helped create a more fully integrated supply chain and allows YCH to provide locally sourced, produced and packaged whole leaf, hop pellet and CO2 hop extract products to brewers around the world.
For many craft brewers, whole leaf hops and/or hop pellets are standard in the brewhouse. While these products continue to comprise the majority of production and sales, CO2 hop extract is finding favor due to its many efficiency-oriented benefits. Through this blog post, we hope to demystify some of the ideas that have historically existed around CO2 hop extract and highlight the value it can bring to breweries big and small.
What is Hop Extract?
Hop extract is pure resin extract of hops containing alpha acids, beta acids, and hop oils. It is much the same as whole leaf or pellet hops but without the solid plant fiber. The extraction process filters out solid particles. As a final product, CO2 hop extract is primarily used in brewing as a kettle ingredient to provide bitterness, however, variety specific flavor/aroma contributions can be expected when used for late kettle or whirlpool additions.
What is Supercritical?
YCH HOPS’ CO2 Hop Extract is produced using a supercritical CO2 process. Simply stated, a supercritical fluid is any substance at a pressure and temperature above its critical point, where distinct liquid and gas phases do not exist. The critical point for CO2 is 87.9 °F and 1,071 PSI. Above this critical point, CO2 is supercritical and behaves like a gas which can flow through a solid matrix (a hop pellet) and dissolve soluble components such as alpha acids, beta acids and hop oils.
From a brewer’s perspective, it’s as if Mother Nature intended for hops, CO2 and beer to be together. CO2 is in the air. It is a naturally occurring compound and is needed for photosynthesis in hop plants. CO2 is in beer. CO2 is produced as yeast metabolize sugars converting wort into beer. The soft resins in hops, having significant flavor and aroma contribution (alpha acids, beta acids and hop oils), are soluble in CO2. The natural utilization of CO2 in hops and beer isn’t something we could just make up.
It is important to note, CO2 is natural, colorless, odorless, tasteless, non-toxic and non-flammable. CO2 is inert in nature, meaning it acts as an anti-fungal and anti-bacterial during the extraction process. As a result, the production process is sterile. The absence of oxygen also reduces the opportunity of oxidation and alpha loss.
Utilizing supercritical CO2 as an extraction solvent allows for gentle, low-temperature treatment of hop pellets during the extraction process. It is a non-polar solvent and does not dissolve polar compounds, thereby leaving behind substances such as heavy metals and many pesticides.
Efficiency & Sustainability
CO2 hop extract has production efficiencies both at our processing facilities and in the brewhouse. Brewers get the benefit of variety specific hop extract without adding solids that must be removed and soak up valuable wort when removed from the wort stream. This creates efficiency in the brewing process and in turn, additional revenue as more beer is produced per batch. In addition, hop extract is highly concentrated, incurring fewer shipping costs and requiring less storage space.
The CO2 extraction process has very low waste outputs as the vast majority of the CO2 is recovered in the extraction process. The extracted hops are sold as cattle feed to local farms, much the same as spent grains, hops and yeast after the brewing process. Altogether, CO2 being a 100% natural compound creates not only an efficient process, but a more sustainable product as well. No chemical additives or modifications are made.
A Story of Shelf Stability
The first lot of hop extract from the Sunnyside facility was produced in March 1999. Since then, Ken Mortensen, the first extract plant employee and current Sunnyside Operations Manager, has had a sample sitting on his desk in a clear glass jar at room temperature which has been opened and sniffed many times. Some have even dared to taste it. We occasionally test this teenage sample in our lab, and amazingly, there has been very little degradation. CO2 hop extract is by far one of the most stable hop products available.
YCH CO2 Hop Extract
YCH HOPS’ extract is part of our new Resinate™ CO2 hop extract derived product line. It is packaged in custom tins with FDA approved, food-grade coating for use with food products. The tins are typically packaged based on grams of alpha acid (GMA) and are labeled on the bottom with 16-9000 food grade ink for easy product identification. This allows the tins to be conveniently added to the brew kettle in whole increments. If partial tins are used, cover and store any unused portion in a refrigerator or freezer.
Introducing CO2 Hop Extract into Beer
There are many methods to adding CO2 hop extract successfully. Two common methods include: removing the lid and adding the open tin to a grant during runoff, or mixing it with hot water/wort in a secondary vessel and pouring the resulting mixture in the kettle during boil. CO2 hop extract is not isomerized until it is boiled during the brewing process. Determining the best method to add CO2 hop extract to the kettle depends on brewing system specifics. Large breweries can install automated dosing systems.
Actual utilization depends on equipment/process specifics. Early kettle additions (60-90 minutes of extract boil time) are used to achieve international bitterness units (IBUs) in wort/beer and will typically lead to the isomerization of 35% of the alpha acids in the finished beer. Adding CO2 hop extract late during kettle boil will result in variety specific flavor and aroma contributions. For best results YCH HOPS recommends using lab analysis of wort/beer to confirm bitterness.
Due to the highly concentrated nature of CO2 hop extract, utilization ratios with whole leaf and hop pellets are not 1:1. To calculate dosage, use the YCH HOPS Dosage Calculator for guidance when creating a new CO2 hop extract recipe. To convert a traditional whole leaf hop or hop pellet recipe into CO2 hop extract for the bittering addition, utilize the YCH HOPS conversion calculator. The calculation for pounds of hop pellets to GMA is (pounds of hop pellets) X 454g X (% alpha acid) = GMA. To download a PDF version of the calculators, click here.
In summary, CO2 Hop Extract offers many brewhouse and overall industry benefits. First, it provides increased brewhouse yields through reduced kettle trub and wort losses. It is the ideal product for adding IBUs to beer without adding more leaf/pellet mass to the brew kettle. Compared to traditional forms of hop products, extract offers increased alpha utilization and rates of isomerization. It is shelf stable, offering extended storage and excellent stability of alpha acids, beta acids and hop oils. Storage requirements themselves are also drastically reduced compared to traditional hop products.
YCH HOPS’ CO2 Hop Extract is produced using a supercritical CO2 extraction process which is all natural and devoid of any solvents or impurities. This process works well for aroma and alpha varieties, so YCH offers variety specific extract products. CO2 Hop Extract provides variety specific hop character and related notes in beer, preserving the quality and natural ratios of alpha acid, beta acid and hop oil and reducing vegetal and polyphenol flavor contribution.
Most importantly, in an industry where demand is outpacing supply, it is becoming crucial for growers, suppliers, and brewers alike to find more efficient solutions. The alpha utilization and yield benefits of CO2 Hop Extract in the brewhouse help to achieve a more efficient hopping rate. Therefore, less hops are needed overall to serve the brewing industry… Stay tuned to the HopWire for more on this in coming weeks.