3. Inventories

The following table sets forth the components of the Company’s inventory balances (in thousands).

	December 31,
	2016		2015
Raw materials
Corn	$	108	$	517
Enzymes and other inputs		309		283
Nutrients		10		4
Finished goods
Ethanol		72		172
Isobutanol		755		-
Jet Fuels, Isooctane and Isooctene		519		514
Distiller's grains		-		13
Work in process - Agri Energy		274		460
Work in process - Gevo		62		109
Spare parts		1,349		1,415
Total inventories	$	3,458	$	3,487

Work in process inventory includes unfinished jet fuel, isooctane, isooctene and isobutanol inventory. Prior to 2016, finished isobutanol located at our Agri-Energy Facility was classified within Work in process – Agri-Energy given the majority of our isobutanol production was being used as feedstock to produce hydrocarbons such as jet fuel, isooctane and isooctene. During 2016, the Company chose to classify isobutanol as a component of finished goods due to the increased production of isbutanol at our Agri-Energy Facility and the positive market development and customer demand for isobutanol being sold directly into the market as a gasoline blendstock.