It seems that torque isn't working with a "big" polygon. By "big" I mean the size of a french department. Could you confirm that? I would like to show the evolution of jobless rate during the last 30 years.
The torque library doesn't currently support polygons. We had an older experimental version of the library that had limited support of polygons, but for production we have limited it to points for now. If you want to show polygons overtime, you can recast them as points,
SELECT ST_Centroid(the_geom) the_geom, some_date_column FROM table_name
And then click options => Table from query to store this as a point table. To run the query on the fly and have a torque visualization, you also need to include the point version of the_geom_webmercator, so,
SELECT ST_Centroid(the_geom) the_geom, ST_Centroid(the_geom_webmercator) the_geom_webmercator, some_date_column FROM table_name
And then the Torque option should appear in the visualization wizard. Hope that helps