Monitoring dissolved oxygen is critical throughout the brewery. Learn how Hamilton dissolved oxygen sensors can bring value to your brewery in this case study at Utepils Brewing in Minneapolis, MN. Dissolved oxygen (DO) in finished beer is a recipe for disaster. While oxygen is required by yeast at the beginning of fermentation to create sterols and unsaturated fatty acids for the synthesis of cell walls, it has a detrimental effect on beer after fermentation is complete.