The deep richness of coffee combined with the brown sugar provides an ideal caramelized crust on your steak. This crust helps hold in the natural flavors and juices so that the steak doesn't dry out prematurely. 
 
We also love the savory taste sensation of this Mexican inspired rub as in addition to the unexpected flavor of coffee you get the fruity heat of the ancho, the sweetness of the brown sugar and for just a dash more heat we also added some De Arbol Chile. 
 
With our rubs we like to shake our seasonings onto our meat and then work it into the meat evenly on both sides and then refrigerate before cooking. Now typically we like to have the seasonings sit for at least 1-2 hours but we found with the espresso rub it is better to only have it sit for 30 minutes to an hour before cooking. 
 
Now while we love this seasoning best on a good steak (i.e. T-Bone or Porterhouse) we also enjoyed it on bolder fish like tuna and swordfish. Hand blended from ancho chile powder, ground sumatra mendheling (fresh dark roasted coffee), Spanish paprika, brown sugar, yellow mustard, sea salt, black pepper, Mexican oregano, coriander, ginger root and de arbol chile powder.