I meant flour, if it helps it's the complete edition and how do I use the manual grinder?
Flour is only used when you do cookies baking session with Sarah at her apartment. We might implement more recipe related to flour in the future. If you have any suggestion, we might be interested to listen.
As for grinder, you need to unlock modern stove (3 gems) through Customise Home screen. Once you unlocked modern stove & put it at your home, there should be grinder below hot water on cooking screen.