The AromaLocTM method to improve wine quality

Dozens of trials in the South Okanagan area of British Columbia over the past eight years suggest that the AromaLoc method increases wine quality and does so by selectively retaining the yeast-derived fruity esters (Jones, 2020). This study reports the findings from wineries located in other areas of North America to determine if unsupervised use of AromaLoc can be as effective as previously found. AromaLoc is a non-invasive method to reduce stripping of aromas by the CO2 released during primary fermentation (Morakul et al., 2013). It does this by treating the escaping headspace gas above fermenting wine with a membrane and a process called vapor permeation. Hydrophobic aroma compounds, plus some CO2, permeate the membrane and are pumped back to the headspace to preserve the aromas that would normally be lost to the atmosphere (Ferreira et al., 1996). Permeated aromatic compounds return to the headspace and result in an increase in these compounds in the fermenting wine below. The membrane is made of polydimethylsiloxane (PDMS), commonly known as silicone, formed into hollow fibers which allow a large diffusion surface area. Aromas permeate PDMS via a solution-diffusion mechanism, meaning the permeating compounds must first dissolve in the PDMS before they can diffuse across. Since PDMS is hydrophobic, the hydrophobic aromas dissolve better into PDMS than hydrophilic compounds (Auner et al,. 2019). The driving force for diffusion is the chemical potential gradient (CPG), determined by concentration and pressure differences between the feed and permeate sides of the hollow fibers. A vacuum pump assists to increase the CPG by creating a partial vacuum.