Abstract: Vessels, including non-symmetric vessels for mixing fluids, are disclosed. In one aspect, the vessel is one that has a non-rotationally-symmetric interior surface. For example, the vessel may have an oblique frustoconical shape. At least a portion of the mixing vessel may have horizontal cross-sections having varying area, in some embodiments. The vessel may be formed from any suitable material, e.g., glass, plastic, or stainless steel. Such vessels may be used, according to certain embodiments, to create single, double or other multiple emulsions, for example, by exposing liquids or fluids contained therein to relatively high shear rates. In some cases, the vessel may be designed to be pharmaceutical-grade and/or meet ASME Bioprocessing Equipment (ASME-BPE) standards. For instance, the vessel may be used under conditions where the vessel is sterile, and/or the vessel may have a polished internal surface.