Chahan Yeretzian

The Battle for Volatile Aromatics Coffee extraction typically involves a trade-off between heat and aroma. While high temperatures are necessary to pull solubles from the bean, that same heat causes the most delicate, floral, and fruity compounds to evaporate into the air before they ever hit the cup. Traditionally, we smell these volatile aromatics as we brew, but they rarely survive the journey to our palate. Sasa Sestic, the 2015 World Barista Champion, has partnered with researchers like Dr. Chahan Yeretzian at Zurich University to solve this problem. Their solution is the Chill Extract Theory, a method designed to flash-chill the first part of the brew to lock in these elusive compounds. The Physics of Flash-Chilling The Chill Extract Theory centers on the idea of rapid thermal transition. By passing hot coffee extract over a chilled surface immediately as it leaves the filter, brewers can retain up to 40% more volatile aromatics that would otherwise be lost to the atmosphere. Research indicates that the first 20% to 30% of an extraction contains the highest concentration of these delicate compounds. When these aromatics remain in the liquid, they shift from being "below threshold" (undetectable) to "above threshold." This doesn't just make the coffee stronger; it introduces entirely new flavor profiles—such as specific floral or stone fruit notes—that are absent in standard brews. Engineering the Paragon Brewer To move this theory from the lab to the cafe, Sestic and his team at Nucleus Coffee Tools developed the Paragon Brewer. Unlike a traditional V60, the Paragon features a height-adjustable stand that holds a specialized chilling rock. This rock is a hollow stainless steel sphere filled with a thermal gel that freezes faster and stays cold longer than solid metal. As the coffee drips from the filter, it spreads over the sphere in a thin layer, maximizing surface area contact for instantaneous cooling. Once the initial, aroma-rich portion of the brew is captured, the rock is swung out of the way, allowing the remainder of the brew to finish at a standard temperature to maintain the coffee's overall body and warmth. Sensory Impact and Competition Controversy The practical impact of this technology is startling. In side-by-side blind tests, chilled extract brews exhibit a significantly more open and "vibrant" structure. While a standard brew might taste "jammy" or "cooked," the Paragon version often presents as fresh, floral, and structured. This effect was so pronounced during a recent competition that judges initially disqualified Sestic, suspecting he had used illegal additives to achieve such intense fruit flavors. It was only after a re-brew under strict supervision that the judges realized the hardware itself was responsible for the chemical change. This innovation provides a new avenue for producers to showcase the true potential of high-elevation crops, ensuring that the hard work done at the farm level isn't lost to the air during the final stage of the process.