Pesachim 74B

מידב דייבי.

the blood flows out. However, in the case of regular stuffing, which is closed on all sides, there is no way for the blood to drain.

נימא מסייע ליה: הלב, קורעו ומוציא את דמו. לא קרעו ⁠— קורעו לאחר בישולו, ומותר. מאי טעמא ⁠— לאו משום דאמרינן כבולעו כך פולטו?

The Talmud suggests further: Let us say that the following Mishnah supports him: With regard to the heart of an animal, one must tear it and remove its blood before one roasts or cooks it. And if he did not tear it beforehand, he tears it after it is cooked, i.e., roasted, and it is permitted. What is the reason the heart is permitted although there is presumably still blood inside? Is it not because we say that as it absorbs it, so it emits it, and therefore as the heart is roasted the blood is absorbed in the meat and then discharged, so that no blood is left in the meat, and whatever is still inside the hollow part of the heart can be removed when it is torn open? This would support the opinion of Rabba.

שאני לב, דשיע.

The Talmud refutes the proof: A heart is different because it is smooth and does not absorb much blood. However, generally one does not necessarily rely on the principle that as it absorbs it so it emits it.

(איני) והא רבין סבא טפליה ההיא בר גוזלא לרב, ואמר ליה: אי מעלי טפליה, הב לי ואיכול! ההיא בסמידא דמפריר.

The Talmud asks: Is that so? Didn’t Ravin the Elder wrap a particular young dove in dough for Rav and roast it, and Rav said to him: If its dough tastes good, give me some and I will eat? Apparently, according to Rav, although the breading absorbed blood, it also certainly discharged it during the roasting. The Talmud refutes this point: That incident involved fine flour [semida], which is crumbly and allows the blood to flow through it.