The Process

Our core process is capturing vapors released during wine fermentation. The condensed essence is a highly aromatic clear wine spirit ranging from 15-45% ABV. The company captures and markets the process output (Aromatica condensate), and manufactures, markets, and supports tools for executing the process (smart condensers). The condensate is comprised of volatile organic compounds (ethanol and aromatics) and water from the wine must.

Wine fermentation is a biological batch process governed by yeast digestion of grape sugars. Carbon dioxide (CO2) production and ethanol emission change over the batch process and there is never a steady-state condition during a fermentation cycle.

The stoichiometry is well understood. When yeast ferment juice into wine, one mole of sugar is converted to equal molar amounts of carbon dioxide (CO2), and ethanol (EtOH):

The majority of CO2 produced and a fraction of ethanol and other aromatic volatiles produced are lost to the atmosphere.

Some useful facts for this process:

• Wine grapes are typically 20-25% sugar by weight
• Each volume of wine produces approximately 60 volumes of CO2
• Ethanol is a polar compound, with one of the highest Henry’s Law Constants, it easily hydrates and resists leaving the liquid phase
• Vaporized ethanol is carried from the developing wine with the CO2 carrier gas
• Yeast fermentation is an exothermic process and tank temperatures, without active cooling, can exceed 32⁰C (90⁰F)
• The dominant parameter affecting vapor emission of ethanol is fermentation temperature
• Fermentation is seasonal and typically occurs between August and November
• Wine fermentation releases many thousands of tons of ethanol vapor into California atmosphere each harvest season

Ethanol lost as a % of total ethanol available with temperature (Fielder and Buamala 1982, Todd Castronovo, and Ouchida 1988):

The following figure is from the 1983 manuscript by Lynn Williams and Roger Boulton. The figure presents a modeled single batch fermentation based on a chemical engineering model of wine fermentation. Important for our understanding is the time-dependent profile of sugar consumption, CO2 production and ethanol emission. The relative positions of the CO2 and ethanol curves remain the same regardless of the batch duration. The ethanol peak lags the CO2 peak as both liquid concentration of athanol in the forming wine (must) and the temperature of the must need to increase before the maximum vapor concentration for ethanol is attained.

References:

Fielder, D.R., and P.A. Baumala 1982. Characterization of ethanol emissions from wineries. Research Division California Air Resource Board. Fig.13 p.53.

Todd, D.F., C.L. Castronovo, and P.K. Ouchida 1988. Ethanol emissions control for wine fermentation tanks. Report #ARB/ML88-027, California Air Resource Board, Monitoring and Lab Division.

Williams, L.A., and R. Boulton 1983. Modeling and prediction of evaporative loss during wine fermentations. Am. J. Enol. Vitic. 34:234-242.