Abstract: The present invention is directed to an apparatus for controlling the absolute viscosity of band seal-preparation liquid in a process to apply the band seal-preparation liquid to seal two part capsules comprising a) a first source comprising a band seal-preparation liquid, a second source comprising purified water, a loop connected from said first source, wherein said loop is connected to the first source, and wherein said band seal-preparation liquid is circulated in one direction through said loop from said first source back to said first source; and an apparatus for measuring the absolute viscosity of said band seal-preparation liquid in said loop to produce a absolute viscosity measurement, and applying the band seal-preparation liquid to a two part capsule in order to create a seal band to seal the two parts together.