The torque (force) required to close the handles on a pair of cam and groove fittings will vary according to the gasket chosen.
Due to the nature of the PTFE® material, the various PTFE® gasket designs will require the most torque, increasing as you go from envelope to encapsulated, and finally, accordion.

PTFE® white Buna filler (TFWB) and PTFE® encapsulated silicone (TES) all contain FDA approved materials.
PTFE® accordion gaskets (TFACC) are recommended for use with viscous (thick) fluids only.
Encapsulated gasket pressure ratings are reduced to 125 PSI for 3/4" - 4" at ambient temperature (70ºF)
PTFE® encapsulated Viton® (TEV) gaskets - maximum operating temperature 200ºF
PTFE® encapsulated silicone gaskets (TES) gaskets - maximum operating temperature 225ºF
Maximum operating temperatures for specific chemicals may be lower.