Reference for Pesachim 148:13

אמר ליה מר בר אמימר לרב אשי אבא האי חלא דחליט ביה חדא זימנא תו לא תאני חליט ביה מאי שנא מחלא מתמהא דחלטינן ביה התם איתיה

He who forbids [holds]: it does indeed bind [the blood]; while he who permits [maintains]: it draws it out. And the law is: it draws it out. Raw meat which turns red, its serum is forbidden;<span class="x" onmousemove="('comment',' This is R. Aha's view; though he permits the meat itself, he agrees that the serum is forbidden.');">²¹</span> if it does not turn red, its serum is permitted. Rabina said: Even if it does not turn red, its serum is forbidden, [for] it cannot but contain streaks of blood. Mar B'Amemar said to R'Ashi: My father did indeed drink it.<span class="x" onmousemove="('comment',' The serum.');">²²</span> Others say: R'Ashi himself drank it. Mar B'Amemar said to R'Ashi: Vinegar which had been used once for contracting [meat],<span class="x" onmousemove="('comment',' Meat was washed in vinegar in order to contract the blood vessels and bind the blood.');">²³</span> my father would not use it again for contracting'.<span class="x" onmousemove="('comment',' Because after it has been used once the vinegar loses its strength to bind the blood in its place.');">²⁴</span> How does it differ from weak vinegar, which may be used for contracting'? - There

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