A grain aeration system facilitates thorough and efficient aeration of grain within a grain bin. The system includes a grain bin having a top vent and a bottom vent. A stand is positioned within the grain bin. A duct includes a loop section supported on the stand and an extension extending from the loop section out through the bottom vent in the grain bin. The duct has a duct wall and a plurality of perforations extending through the duct wall. A blower drives air flow out of the bottom vent creating air flow into the grain bin through the top vent and into the duct wherein the blower is configured to aerate grain positioned within the grain bin.