S39: Analysis and Optimization of SO2 in a Seasonal Lager Beer

It is well known that SO₂ as sulfite can be produced in significant quantities in beers fermented with lager yeasts and that it provides some antioxidant protection to beer by inhibiting the formation of free radicals or reducing those that do form, thereby providing improved flavor stability.  Many factors can effect SO₂ production by yeast during fermentation and potentially its preservation during subsequent processing, including aeration protocol and yeast pitch.  This study involved the evaluation and adjustment of several key process variables to enhance yeast production of SO₂ within acceptable limits in a seasonal lager beer without adversely affecting beer quality and without detriment to the yeast.  In addition, a well known method of determining the SO₂ content in beer utilizing formaldehyde/p-Rosaniline colorimetric methodology was modified and adapted in-house that relied on automated segmented flow analysis without the use of mercury.