All natural grass fed beef. You can taste the difference in the patty. Truffle fries were lacking on the truffle taste. Like they barely drizzled any truffle oil on it. If the fries were better I'd give 4 stars. The inferno burger I had was topped with pepper jack and jalapeños. Very tasty. Also, the menu up front had no description of what each type of had in it. That's another minus.