Studying Superheated Stevia with Polynomial Chaos in Quantum ESPRESSO: opEn-Source Package for Research in Electronic Structure, Simulation, and Optimization

Coffee is one of the most consumed beverages by people on a daily basis. Many coffee drinkers use stevia to sweeten their drinks. Here we show the superheating of microwaved coffee upon adding stevia, where according to critical bubble theory, stevia granules act as nucleation sites for bubbles to form and the first-order phase transition to occur. Based on quantum mechanical simulations of the active component of stevia's structural relaxation by minimum ground state electron density energy forces, a hypothesis is devised for the origin of this stevia-induced superheating due to interactions with higher frequency, mobile carboxyl and hydroxyl group side-chains present above the base molecular plane of steviol [1], which enable stevia granules to act as bubble nucleation sites. Superheating of water upon adding pebbles after sealed microwaving has been previously observed [2]; however, the observation of superheating of coffee upon added stevia is currently not understood, even though the rise above the boiling point could be captured within the uncertainty of Newtonian cooling dynamics by polynomial chaos expansion. This study has implications for understanding the superheating of particulate accumulation in high-temperature, ambient-pressure environments, such as fuel in engines.