"Service" item type is the solution for dealing with consumables.Although, you should consider a work-around to get these items expensed.
DynamicAccounting has came up with a smart work-around for this issue, you need to setup a “Consumables” profit and loss account as the Inventory account for these items. When the items are issued to a department, they get expensed to the requesting department as the Inventory Offset account.
This charges out consumables to the correct department but ensures that any leftover items are still expensed at month end as general consumables.
Best Regards,
Mahmoud AlSaadi