A method for filling a container with a plurality of particles includes the step of filling a radially flexible container through a large diameter with a plurality of particles to a fill level. The method also includes the step of reducing the large diameter of the radially flexible container to a smaller fill diameter in vertical relationship to the fill level as the fill level rises during filling of the flexible container. The method also includes the step of varying the vertical relationship between the fill level and the smaller fill diameter in response to the density of the particles.