Add the required amount of hot water in a vessel and heat to above 85°C . Add HPMC gradually while slow stirring. HPMC floats on the surface of the water at the beginning, and then disperses gradually and forms uniform slurry. The solution is cooled by stirring. Or, add 1/3 to 2/3 of required hot water, then heat to above 85 °C . Add HPMC to gain hot water slurry and then add the remaining ice water or ice. Keep stirring. Cool the final mixture.