The beer tax return is Form 1650. If you file monthly, it's due the 15th of the month following the tax period (e.g. October's return is due November 15). If you file quarterly, it's due the 15th of the month following the end of a quarter. For example, the 1st quarter report is due April 15. If the due date falls on a weekend or holiday, the payment is due on the next business day.
Read more about beer tax here: http://tax.idaho.gov/i-1021.cfm
