If you thought all you needed for a great pint was a good recipe and a steady hand, think again. According to scientists at São Paulo State University (UNESP), mastering a bit of chemistry might actually be essential for brewing better beer. They recently published a study comparing the usual hop extraction methods with a more advanced technique—supercritical CO2 extraction—already in use by some forward-thinking brewers. The results? A leap forward in preserving hop bitterness and aroma that could transform the beer experience.
The study, published in Biomass Conversion and Biorefinery, was conducted by researchers centered at São Paulo State University (UNESP) in Brazil’s Vale do Ribeira region. It compared conventional extraction (using organic solvents or steam stripping) with supercritical CO2 extraction, which, as the name suggests, uses carbon dioxide under high pressure and temperature in its supercritical state. The CO2 method not only achieved up to 72% α-acids (the compounds responsible for bitterness) versus around 15% with traditional methods but also preserved the unique terroir and sensory characteristics of the hops. This translates to beer with richer bitterness and aroma profiles without sacrificing the hops’ signature flavors.
Hops play a vital role in brewing by imparting bitterness, aroma, and flavor. During beer production, hops are added to the wort—the sweet liquid extracted from malted grains—primarily during the boiling phase. This process enables alpha acids in hops to isomerize, producing the characteristic bitterness that balances malt sweetness. Beyond bitterness, hops contribute floral, citrus, pine, and other aromatic notes, depending on the variety. Extraction of hops is the process of isolating these favorable compounds, usually to create hop pellets, oils, or extracts that brewers can use precisely.
Supercritical CO2 extraction differs fundamentally from traditional solvent or steam methods by utilizing CO2 in a state where it exhibits both gas-like penetration and liquid-like solvency. This allows for selective, efficient extraction of bitter acids and aromatic oils without the environmental downsides of petroleum solvents or the inefficiencies of steam. The technology is established in hops production in the US and Germany and is gaining traction in Brazil, where researchers and brewers see potential to boost hop quality and supply, especially as the country has so far grown less than 1% of the hops it needs despite being a top global beer consumer.
Climate change poses a mounting threat to traditional hop cultivation due to increased droughts and heat waves that reduce yields and bitterness compounds. European hop production is already seeing yield declines up to 18% and alpha acid losses up to 31% projected by 2050. Against this backdrop, Brazil’s rapidly growing beer market, expected to expand substantially through 2035 with a strong surge in craft brewing, is keen on developing domestic, sustainable hop production to reduce risks and import dependence. The supercritical CO2 method offers Brazil not only a way to preserve hop quality amid climate challenges but also to innovate green chemistry cycles by capturing valuable extracts and repurposing hop waste for other industries.
So, while brewers have traditionally wrestled with hops boiled into submission, Brazilian scientists are quietly coaxing their essence out with carbon dioxide magic—an approach that’s cleaner, greener, and most importantly, tastier. As the global beer market swells and hops face growing climatic headwinds, CO2-powered technology—now taking root in Brazil alongside established users—pairs perfectly with the world’s ambitious thirst for both innovation and beer.
This could well be the rise of the era where hops don’t just get boiled—they get supercritically liberated. Cheers to that!
