An agitation element includes a base, a shaft extending from the base generally along a vertical direction, at least one fin, and a plurality of ribs. Each of the plurality of ribs extends from the base and radially outward from the shaft. Each of the plurality of ribs includes a radially outward portion, the radially outward portion including two opposing entirely convex sidewalls and defining a maximum width and a maximum height, wherein a ratio of the maximum width to the maximum height is between 0.8 and 1.2. Each of the plurality of ribs further includes a radially inward portion, the radially inward portion including two opposing sidewalls.