Gelatin is a collagen derived from animal sources with a large molecular weight containing a positive charge. When prepared and introduced to beer this positive charge attracts the smaller negatively charged yeast cells and aids in accelerated sedimentation.
Dissolve gelatin in 160 degree water using a high shear mixer to completely dissolve the powder. Introduce this to the beer to be treated after chilling to 32 degrees on transfer to the aging or serving tank for optimal dispersion. Application rates should be determined by brewery scale trials.
From the Gelatin Manufacturers Institute of America Gelatin Manual:
Clarification of Beverages and Juices
Gelatin has traditionally been used to clarify wine, beer and fruit juices. Fining of these beverages requires only 40 to 80 parts per million of a 100 to 200 Bloom gelatin. In practice, a diluted (1-3%) gelatin solution is introduced into the top of the tank and then allowed to settle before filtration.