Styrene butadiene copolymer rubbers (SBR) are produced by aqueous emulsion polymerization, in which the monomers are polymerized in an aqueous system containing a suitable free radical polymerization initiation system and emulsifying agents. Emulsion polymerization results in a colloidal dispersion of rubber in water, namely a latex. It is then necessary to recover the rubber from the latex to obtain solid particles, or rubber crumb, in a suitable form for finishing, packaging and shipping.