Ossetra (Osetra or Asetra) caviar comes from the Ossetra sturgeon (Acipenser guelenstaedtii), weighing 50-400 pounds and living up to 50 years. Ossetra caviar ranges from warm brown to green-gray in color, to dark blue to jet black or even white. Ossetra caviar is said to have a nutty flavour and so is prized as an elite caviar.