A method of preparing a composition comprising crystalline biomolecules, wherein the crystalline biomolecules are proteins comprising one or more polypeptide chains, said method comprising: a) forming a fluidized bed of crystalline biomolecules in a rotating chamber comprising an inlet and an outlet, wherein the fluidized bed is created by rotating the chamber about a substantially horizontal axis to create a centrifugal force (F centrifugal ) in said chamber, flowing a first stream of a first solution through the inlet in a direction opposite to the direction of the F centrifugal and at a first flow rate (FR1) having a force (F FR1 ) which counter balances F centrifugal , and collecting the first solution from the chamber while substantially maintaining the formation of the fluidized bed of crystallized biomolecules; b) performing step (i), (ii), or (iii): i. flowing a second stream of a second solution to replace the first stream of the first solution while substantially maintaining the formation of the fluidized bed of crystallized biomolecules; ii. concentrating the crystallized biomolecules within a region of the chamber by changing FR1 to a second flow rate (FR2) having a force (F FR2 ) which is less than F centrifugal or by increasing the speed of rotation of the chamber to increase F centrifugal to a level which is greater than FFR1; iii. a combination of step (i) and step (ii); and c) flowing a second stream into the chamber through the outlet in a direction which is parallel to the direction of the F centrifugal to remove the crystalline biomolecules from the chamber. a) forming a fluidized bed of crystalline biomolecules in a rotating chamber comprising an inlet and an outlet, wherein the fluidized bed is created by rotating the chamber about a substantially horizontal axis to create a centrifugal force (F centrifugal ) in said chamber, flowing a first stream of a first solution through the inlet in a direction opposite to the direction of the F centrifugal and at a first flow rate (FR1) having a force (F FR1 ) which counter balances F centrifugal , and collecting the first solution from the chamber while substantially maintaining the formation of the fluidized bed of crystallized biomolecules; b) performing step (i), (ii), or (iii): i. flowing a second stream of a second solution to replace the first stream of the first solution while substantially maintaining the formation of the fluidized bed of crystallized biomolecules; ii. concentrating the crystallized biomolecules within a region of the chamber by changing FR1 to a second flow rate (FR2) having a force (F FR2 ) which is less than F centrifugal or by increasing the speed of rotation of the chamber to increase F centrifugal to a level which is greater than FFR1; iii. a combination of step (i) and step (ii); and i. flowing a second stream of a second solution to replace the first stream of the first solution while substantially maintaining the formation of the fluidized bed of crystallized biomolecules; ii. concentrating the crystallized biomolecules within a region of the chamber by changing FR1 to a second flow rate (FR2) having a force (F FR2 ) which is less than F centrifugal or by increasing the speed of rotation of the chamber to increase F centrifugal to a level which is greater than FFR1; iii. a combination of step (i) and step (ii); and c) flowing a second stream into the chamber through the outlet in a direction which is parallel to the direction of the F centrifugal to remove the crystalline biomolecules from the chamber. <EOS>