A laundry appliance includes an infuser into which users may insert a dissolvable treatment material, such as detergent pods of scented pellets. The diffuser may be removably inserted into a receptacle at least partially contained within the cabinet of the laundry appliance. One or more of a moveable cap or lid may be configured to cover an opening at the top of the receptacle, thereby sealing the receptacle. Water or air may be introduced into the receptacle through a fluid inlet line. The water or air may pass through openings in the infuser and interact with the dissolvable treatment material to produce a treatment mixture of treatment material and water or air. The treatment material may then exit the receptacle through a fluid output line, where it may be delivered to a fluid distribution element extending into the laundering chamber of the laundry appliance. The fluid distribution may then distribute the treatment solution into the chamber and onto the articles of laundry. A controller of the laundry appliance may be configured to allow the introduction of water or air to the infuser at a predetermined time based in part on the length of the laundry cycle and/or the rate at which the dissolvable treatment material dissolves.