The analyzer of the present invention is specifically adapted to provide moisture determinations for foods and other agricultural material. It allows the operator to introduce a precise weight of sample into a crucible in a closed furnace in a controlled environment through an access port in the furnace cover. The access port in the cover can be tapered to allow easy access to an underlying aligned crucible and allow an operator to add and remove sample material from the crucible until a precise desired sample weight is reached as measured by a balance within the furnace. The access port is enclosed by an insulated cover after the samples are sequentially placed in the crucibles.