The Fermentation Activity Profile is a relative record of the total sugars in solution, both fermentable and non-fermentable. Sugars absorb blue light. As fermentation proceeds, the amount of blue light returning to the sensor increases as the amount of all sugars in the tank decreases and less blue light is absorbed. The Fermentation Activity Profile trends downward over time as fermentation progresses. The Fermentation Activity Profile will appear much more dynamic than the SG Profile.