cur·dle 
/ˈkɚdl̟/ verb
cur·dles; cur·dled; cur·dling /ˈkɚdl̟/ verb : to thicken and separate into liquids and solids : to form curds [no obj] ▪ The milk has curdled. [=the milk is sour] ▪ Too much heat will make the custard curdle. [+ obj] ▪ Too much heat will curdle the custard.
make someone's blood curdle — see blood
