Assertion: buttermilk's butter | /r/MadeOf | the milk fat
Facets:
Source sentences:
text: Cold or warm gruel cooked from barley or rye flour was added to skimmed sour milk (butter was made from the milk fat).
text: Cold or warm gruel cooked from barley or rye flour was added to skimmed sour milk (butter was made from the milk fat).