The Ottawa cell is designed to produce shear stresses in
a specimen by forward extrusion. As the plunger of the
Ottawa cell is moved down the food specimen is
compressed. As deformation continues the food is
extruded through an insert in the bottom of the cell.
The insert may have an array of equally spaced holes or
equally spaced, parallel wires. The force required to
extrude the specimen through the insert relates
to firmness.