Question: I just purchased chicken hearts. May I cook them as is?
Answer: The Torah (Vayikra 17) states: “And any man among the Jewish nation or the stranger who resides among them that will eat any matter of blood, I shall set my face against the soul that eats blood and I shall cut it off from the midst of its nation.” The Torah states explicitly in several places that the blood which is forbidden for consumption refers to the blood of either domesticated or non-domesticated animals or fowl.
Due to the prohibition to consume blood, we are obligated to salt meat before cooking it, for salt draws out the blood from meat that it is placed on. Nowadays, most cuts of meat and poultry are sold after they have already been salted and soaked in accordance with Halacha in the slaughterhouse. Nevertheless, there are cuts of meat that are sold without already being salted for several reasons.
Heart is sold in stores without being koshered first and there is still blood in it and it may therefore not be consumed until it undergoes a halachically valid koshering process. The reason why heart is not salted before it is sold is because when the animal or bird is slaughtered, a large amount of blood is collected in the heart and it is like a container for this blood and it cannot be expelled through salting alone. Thus, even if they would salt the heart, this would not be sufficient to release the blood contained in it and consumption of the heart would still be absolutely forbidden.
Before the heart is salted, it must be torn open and the blood inside it must be washed off with water and only then may it be salted. Tearing the heart refers to cutting it at least once deep enough that it reaches all of the corridors of the heart along either its entire length or width. The Poskim write that some have the custom to cut the sinews inside the heart as well so that no blood remains collected within it. (These sinews are recognizable within the heart as they look like little tubes.)
After doing so, one should salt the heart well by covering it with fine cooking salt on all sides and leave it in this matter for approximately an hour on top of a rack or other perforated utensil so that all the blood can drip out of it.
If one does not wish to salt the heart (or any other piece of meat for that matter), one may kosher it by grilling it (preferably, one should place a small amount of salt on the meat and only then grill it) since grilling also causes the blood to flow out of it and it will then be permissible for consumption. Even when wishes to kosher the heart by grilling it, one must tear it properly as we have explained above regarding salting the heart. Restaurants which customarily stick the heart onto a skewer and grill it as such without adequately tearing it are causing the public to sin. Hagaon Harav Shalom Mesas zt”l, later former Chief Rabbi of Jerusalem, warned the public that it is imperative that the koshering of the heart be performed only after the heart is torn open properly by cutting it deeply with a knife, as we have explained.
Furthermore, the Siftei Kohen quotes the Piskei Recanati who writes that it is customary to cut off the pointed edge of the heart in order to remove the powers of impurity from it which is a Kabbalistic concept. The Kaf Ha’Chaim writes that if one forgot to cut off the pointed edge of the heart before cooking it, it may be done afterwards as well.
Summary: Chicken hearts sold in stores are not yet koshered and may not be cooked as is. One must cut it with a knife deeply along the length of the heart; some have the custom to also cut all of the tubes located in the heart so no blood remains inside. After this is done, the heart should be thoroughly washed off and it may then be salted or grilled in order to complete the koshering process.