A composition is contained a blend zone prior to refining containing non-fibrillated virgin cellulose fibers, waste/recycle cellulose fibers or both; cellulose ester fibers, water, and one or more additives comprising fillers, internal sizing agents, biocides, process anti-foaming agents, colorants, optical modifiers, or a combination thereof. An in-line mixer can be used for adding the additives, and the consistency of the composition is lowered relative to a feed of material from a hydropulper.