A rotational rheometer comprising: a double wall cup (107, 201, 307, 501, 805, 905, 1005) having an inner cylindrical wall (207, 513) and an outer cylindrical wall (210, 506) forming an annular chamber (110, 206) and a central cylindrical chamber; a cylindrical bob (106, 202, 302, 502, 802, 902, 1002) having a top disk portion, a hollow cylindrical portion and a shaft (111, 304, 504) attached to the center of the top disk portion; a motor coupled to the double wall cup (107, 201, 307, 501, 805, 905, 1005) configured to rotate the double wall cup (107, 201, 307, 501, 805, 905, 1005); a transducer coupled to the cylindrical bob (106, 202, 302, 502, 802, 902, 1002) configured to impose axial oscillations on the cylindrical bob (106, 202, 302, 502, 802, 902, 1002); wherein the inner cylindrical wall (207, 513) of the double wall cup (107, 201, 307, 501, 805, 905, 1005) comprises openings at its lower end that allow fluid communication from the annular chamber (110, 206) to the central cylindrical chamber; and wherein the cylindrical bob (106, 202, 302, 502, 802, 902, 1002) has apertures (320, 520) just below its top disk portion that circumscribe a substantial portion of the circumference of the top disk, wherein the apertures (320, 520) are configured to substantially reduce the total surface area of menisci that would be formed between the top surface of a fluid in the annular chamber (110, 206) and the cylindrical bob (106, 202, 302, 502, 802, 902, 1002) when the annular chamber (110, 206) is filled with test material and the cylindrical bob (106, 202, 302, 502, 802, 902, 1002) undergoes axial oscillations. a double wall cup (107, 201, 307, 501, 805, 905, 1005) having an inner cylindrical wall (207, 513) and an outer cylindrical wall (210, 506) forming an annular chamber (110, 206) and a central cylindrical chamber; a cylindrical bob (106, 202, 302, 502, 802, 902, 1002) having a top disk portion, a hollow cylindrical portion and a shaft (111, 304, 504) attached to the center of the top disk portion; a motor coupled to the double wall cup (107, 201, 307, 501, 805, 905, 1005) configured to rotate the double wall cup (107, 201, 307, 501, 805, 905, 1005); a transducer coupled to the cylindrical bob (106, 202, 302, 502, 802, 902, 1002) configured to impose axial oscillations on the cylindrical bob (106, 202, 302, 502, 802, 902, 1002); wherein the inner cylindrical wall (207, 513) of the double wall cup (107, 201, 307, 501, 805, 905, 1005) comprises openings at its lower end that allow fluid communication from the annular chamber (110, 206) to the central cylindrical chamber; and wherein the cylindrical bob (106, 202, 302, 502, 802, 902, 1002) has apertures (320, 520) just below its top disk portion that circumscribe a substantial portion of the circumference of the top disk, wherein the apertures (320, 520) are configured to substantially reduce the total surface area of menisci that would be formed between the top surface of a fluid in the annular chamber (110, 206) and the cylindrical bob (106, 202, 302, 502, 802, 902, 1002) when the annular chamber (110, 206) is filled with test material and the cylindrical bob (106, 202, 302, 502, 802, 902, 1002) undergoes axial oscillations.