Abstract: A mixer includes an elongated flexible sleeve that is supported in a housing in a vertical orientation and has a mixing shaft extending therein with a plurality of blade holders supported on the shaft and each blade holder supports a plurality of blades. A deforming means extends around the flexible sleeve and is rotatable about a vertical axis by suitable reciprocating or rotating drive members to prevent accumulation of materials on the inner surface of the sleeve. The blade holders are preferably formed as an integral part of a mixing apparatus and each mixing blade is preferably individually supported on a holder to be infinitely adjustable and effect the mixing capabilities of the assembly. The flexible sleeve can be tensioned between upper and lower ends.