Quotation על חולין 209:26

I already explained earlier that what is permitted to the common masses cannot be applied to the Perushim (those who practice Separation) for it is incumbent on them to distance from what is repulsive, or the like and the like of the like. As, Mar Ukba said: "In this matter I am as vinegar derived from wine compared with my father. For if my father were to eat flesh now he would not eat cheese until this very hour tomorrow, whereas I do not eat [cheese] in the same meal but I do eat it in my next meal." (Chulin 105a). There is no question, the Halacha was not like his father did, for if it were, Mar Ukba would not have acted against this. Rather, his father was stringent in this due to his Separation. Therefore, Mar Ukba would call himself "vinegar derived from wine", for he did not measure up in Separation as much as his father.