grist 
/ˈgrɪst/ noun
/ˈgrɪst/ noun Meaning:
grist for your/the mill (US) or Brit grist to your/the mill
: something that can be used for a particular purpose
▪ Now that he's a writer, he regards his difficult childhood experiences as grist for the mill. [=he regards them as material that he can use as a writer]
▪ Now that he's a writer, he regards his difficult childhood experiences as grist for the mill. [=he regards them as material that he can use as a writer]
