I work at a brewery and we currently use QB Desktop Pro (and have for a couple years now) to handle all of our sales receipts to accounts ordering beer, and apparently the person that set this up input all of our available kegs as Service types.  What we're wanting is a better way to track inventory on hand (currently just kegs of beer, no bottles or cans or anything else).... is there a better way to move those items over or is it even possible?  And is it reflected on all the past transactions?  I took a look just now and the option/dropdown appears to be gray-out so you can't click to change it.

We don't use QB for really much else... just receiving kegs into inventory, and then issuing sales receipts, and wanting the inventory to be reduced appropriately.  Hopefully I've explained this well; I'm definitely not well versed in QB, and no one else here is, either (the joys of a small business).  Any general advice on the topic would be appreciated!