Steeping of tea not only involves extracting the soluble components of the tea from the tea leaves, but also creating conditions where reactions can occur among the various tea components depending on the type of tea, and steeping conditions. The term steeping is now being used to describe treatments that can be applied to e-liquids after they are formulated. Such treatments are believed to improve the hedonic properties of the aerosols generated from the e-liquids. Some websites advertise pre-steeped ready to use e-liquids. Various steeping conditions can be found on the Internet. These range from allowing the e-liquid to remain in the dark for days with or without occasional opening of the container, to high-speed mixing, and to use of ultrasonic baths for rapid steeping (e.g. several 30-minute treatments). However, such treatments can also result in heating of the sample depending on the power setting used, the amount of water, and the number and nature of the containers of e-liquid used in the bath. Bath and e-liquid temperatures can exceed 70°C. Consequently we conducted a study to determine chemical changes that occurred after four 30-minute treatments separate by 30-minute cooling periods in a 70-watt DSA Ultrasonic cleaner. Each e-liquid tested was formulated from commercial flavor concentrates (4 mL), 50/50 PG/VG mix (6 ml) and 100 mg/mL nicotine in VG (4 mL) and steeped in capped 1-oz jars. Samples before and after steeping were analyzed by LC using several columns and conditions such as Cogent Phenyl Hydride column with UV detection at 280 nm and gradient elution, 62/38/0.1 ethanol/water/TFA to 33/67/0.1 and the reverse gradient. Excessive steeping with ultrasonic cleaner reduces aromatic aldehydes.