Kaolid+: A Lid-Type Olfactory Interface for Modulating Sweetness Perception

Taste is not shaped by the tongue alone: smell and vision also influence how a beverage is experienced. We present Kaolid+, a lid-type olfactory interface that routes aroma either toward the nose or through a straw, while illuminating the drink with RGB light. This form factor allowed us to compare orthonasal and retronasal aroma delivery under a closely matched setup, and to compare subjective taste ratings across no-light, aroma-congruent orange-light, and aroma-incongruent blue-light conditions under retronasal orange aroma delivery. In a within-subjects design with unflavored carbonated water and orange aroma, the retronasal condition received higher Perceived Sweetness and Flavor Change ratings than the orthonasal condition; overall acceptability did not differ significantly between the two methods. Under retronasal delivery, the orange-light condition was associated with higher Perceived Sweetness ratings than the no-light condition, and the orange-light condition was rated higher than the blue-light condition for overall acceptability, sweetness, and naturalness. Kaolid+ received a mean SUS score of 77.63, indicating good usability. The results position Kaolid+ as a smart beverage interface for studying lid-integrated olfactory actuation and visual cueing during everyday drinking, and provide initial evidence that these device conditions may be associated with changes in sweetness-related ratings within the tested orange-aroma carbonated-water scenario.