About two months ago I delivered to a private client a (monthly-basis) prediction model for ethanol prices that included Brent -- in logarithm -- as a predictor

About two months ago I delivered to a private client a (monthly-basis) prediction model for ethanol prices that included Brent -- in logarithm -- as a predictor. I know the monthly spot average of that statistic (fetched from FRED, the Fed of St. Louis system) won't turn negative, but still...