Assessing the sensory and physicochemical impact of reverse osmosis membrane technology to dealcoholize two different beer styles

A pilot scale dealcoholisation unit fitted with reverse osmosis (RO) membranes was used to directly compare two beer matrices (stout, lager, ~ 5% ABV) and their dealcoholized counterparts (~0.5% ABV), for physicochemical properties (volatiles, pH, ABV, polyphenols, bitterness) and sensory profiles using a trained descriptive panel (n = 12). The efficiency and consistency of RO membranes were evaluated by replicate dealcoholisation trials (n = 3) for each beer. Statistical analysis revealed significant reductions (p < 0.05) in key volatile compounds with linear structures (ethyl octanoate, octan-1-ol) compared to those with increased levels of branching (3-methylbutyl acetate, 2-methylpropan-1-ol). Significant reductions (p < 0.0001) in ‘fruity/estery’, ‘alcoholic/solvent’, ‘malty’, ‘sweetness’ and ‘body’ sensory attributes were also discovered. Finally, longer processing times for the stout across replicate trials suggested membrane clogging, whilst differences in volatile reduction suggested membrane fouling. This novel research proposes compound structure, rather than compound size, impacts RO membrane permeability and resulting sensory quality.