When will a judge be barred from making comments in the courtroom that constitute "extrajudicial bias"?

Nevertheless, we have made it clear that there is an exception to the general rule that courtroom statements are not enough to warrant recusal and that "extrajudicial " bias is required. That exception is applicable when the petitioner can demonstrate through expressions of opinion and rulings made in the course of judicial proceedings that the bias is "pervasive." United States v. Monaco, 852 F.2d 1143, 1147 (9th Cir.1988) (An exception to the extrajudicial bias rule is made "when a judge's remarks in a judicial context demonstrate such pervasive bias and prejudice that it constitutes bias against a party."). ³