|One of these things. |
You can find them in the deli section.
- Acetone. Big time.
- No acetone whatsoever. Smelled completely normal and fresh.
To deter any off flavors, either grate Parmigiano-Reggiano and refrigerate or grate and keep it at room temperature. These two methods should never be mixed. Exposing the grated cheese to a combination of cold and then room temperatures can create an off acetone-like aroma in the cheese.
Upon reflection I realized, yes, this makes perfect sense. That grocery store had been storing its grated P-R at room temperature in a center display aisle, and then they moved it all to the cold case, thereby apparently ruining most of their stock - all except for the brand new stock at the very back of the display case.
So file this little tidbit in your "learned something new today" category, and remember to sniff your P-R before you pay for it. Those little tubs cost about ten bucks apiece, so you don't want to take home a dud that has been mis-handled by grocery store personnel. And then once you get it home, maintain the temperature at which you found it in the store.