Matthew Leroy Ehens, 38, of Arroyo Grande, has been sentenced to 8 years-to-life in state prison.
Monday's sentencing came after he was convicted on Aug. 25 on felony charges of torture and elder abuse.
During an argument on Aug. 2, 2019, Ehens poured boiling peanut oil on his 79-year-old adoptive mother and stabbed her in the back with a large kitchen knife. He fled in his car, which led to a high-speed chase with law enforcement, ending when Ehens crashed his vehicle and was arrested.
The victim suffered serious burns on over 17% of her body and underwent extensive medical treatment, the District Attorney's Office says. She had to be hospitalized for a month and had a skin grafting operation.
The sentence was announced on Monday by San Luis Obispo County District Attorney Dan Dow.
The Arroyo Grande Police Department and the San Luis Obispo County Sheriff's Office investigated the case with assistance from the District Attorney's Bureau of Investigation.