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Liver and Gelatin

  • Rav David Brofsky

     Since the blood in a bird or animal is prohibited, it must be removed before cooking.  There are two ways that this can be done, either by salting or by broiling.  Although fifty years ago, most salting was still done in the home, today this is rare.  Generally, the meat is salted in the packinghouses.  The one exception is liver, which cannot be kashered by salting but only by broiling.  Hence, most of today's shiur will deal with the preparation of liver.  But first, in the interest of informed kosher consumerism, some modern ramifications of the laws of the salting.


  1. Salting


     There are other cases where salting cannot be done.  For instance, if the meat has aged for three days after the slaughter, it can no longer be salted effectively, since it has dried.  This restriction is not mentioned at all in the Talmud, but derives from a "chumrat ha-geonim" (a restriction derived from the custom in the yeshivot of Babylonia in the period after the conclusion of the Talmud).  In such a case, it can be kashered only by broiling.  The way to prevent this from happening is to wet the meat during the three days.


     When meat was basically prepared at home, it was understood that wetting the meat to prevent the drying basically meant soaking it for a short period of time.  When meat processing became industrialized, and meat was often shipped by rail long distances between the centralized slaughter houses and the processing plants, a method was created whereby the meat would be sprinkled automatically in the rail cars.  The question arose whether this would be sufficient, or whether it had to be soaked and not only sprinkled.  Although many poskim were reluctant to allow this leniency, Rav Moshe Feinstein ruled that the meat could be salted; though it was not an optimal solution (Igrot Moshe YD 53).  His reasoning proceeded from the fact that the restriction on meat that was more than three days old was not based on Talmudic law but was only a chumrat ha-geonim; hence, there was room to be more lenient.


There is a difference of opinion among the poskim whether the three-day restriction applies to frozen meat (i.e., can it be salted after thawing).  The question is whether freezing prevents the drying that would make salting invalid.  Usually, within the United States, meat is salted in the packinghouses before being frozen.  In Israel though, some frozen meat is imported from South America and other places and salted in Israel after being thawed.  If you remember when we spoke of the concept of "glatt," we noticed that nowadays the term is often used to mean a higher standard of kashrut in other ways than only the question of the treifot of the lung.  This is one of those uses - in Israel, "frozen glatt" is salted before freezing, whereas "regular" (non-glatt) kosher (imported) frozen meat is not.


     In any event, in nearly all cases today, the kosher consumer buys meat that has already been kashered.  There is however one exception, and that is liver.


     The Talmud states that because of the large amount of blood present in the liver, salting is not sufficient to kasher it.  The only acceptable method is broiling, which is more effective in drawing out the blood.  Generally, chicken livers, and often beef liver, is sold raw, and hence, unkashered, and the kashering must be done in the home.  This is the one case where the average consumer will directly meet up with the laws of kashering meat, and therefore we will devote a special section to understanding the process and describing how it should be done. 


  1. Liver


Yalta, the wife of Rav Nachman, is the source of a statement in the Talmud with a great deal of philosophic significance for understanding the attitude of the Torah towards asceticism and prohibitions in general.  For this shiur, we are interested in only one of her examples, but it is worth thinking about the statement in a more general context as well.


Yalta said to R. Nachman: Everything that the Torah prohibited, it permitted a corresponding thing. 


nida  -   the pure blood (after birth);

the fats of domestic animals  -  the fats of wild animals;

pig  -  "mocha" (the marrow of the "shibuta" fish, which has the same flavor);

a married woman  -  a divorcee while her husband is still alive;

A brother's wife  -  yevama….

I would like to eat some milk-and-meat.

R. Nachman told the cook to give her some barbecued udder.

(Chullin 109b).


Rashi explains the parallelism between blood and liver by stating that the liver is "completely congealed blood." This is presumably a deliberate exaggeration, as Rashi himself continues to explain that the taste of the liver is the taste of blood.  In any event, this does express the rabbinic view that there is a surplus of blood present in the liver.  For that reason, salting as a method of purging blood, which is used for all other cuts of meat, is not acceptable for the liver.  The only acceptable method is broiling over an open flame, which draws out the blood. 


There are two areas which are relevant here.  The first is the exact method of effective purging through broiling.  A second issue revolves around the fact that any utensils used in the broiling are liable to absorb the blood that is being drawn out of the liver and are therefore themselves not kosher.  This presents both a problem for the liver itself, and of course for any subsequent use of those utensils. 


  1. The broiling of the liver. 


If the liver is whole, it must be first slashed vertically and horizontally, in order to allow the blood to drain away easily.  If a slice of liver is being kashered, this is not necessary.  Chicken livers should be cut in a few places.


It is customary to wash the liver before the broiling, in order to remove any external blood.


The Rama states that it is customary to lightly salt the liver.  This is actually a problematic procedure, since if the liver is left in the salt for a long period, it will actually be prohibited.  Therefore, the Rama warns that it should be salted only immediately prior to being placed on the fire.  After the completion of the broiling, the liver should be washed again, especially if, in accordance with the custom, it has been salted. 


In any event, if either the washing or the salting has been omitted, the liver is still kosher.


There exists a disagreement among the poskim whether the three-day rule mentioned above would apply to liver.  This would not prevent the broiling, since, as we saw above, meat can be broiled (though not salted) even after three days.  However, some poskim prohibit cooking the liver after the broiling if it has been broiled only after three days.  If, however, the meat has been frozen for more than three days (which, as we saw above, is itself possibly sufficient to prevent the three-day drying), it is generally accepted that one may kasher the meat by broiling and then cook it.  This is due to the combination of two separate considerations: 1) That in any event, meat that has been kashered by broiling can be cooked even if three days expired before the broiling; 2) Even if that is incorrect, freezing prevents the drying process which interferes with kashering. 


The liver should be exposed to the fire in such a way that the blood can flow freely away, so that the meat does not rest in any manner in the blood (or any other liquid).  Usually, this is done either with a fork or spit over an open fire, or on a wire mesh.  Many poskim allow the use of a lacerated broiling surface, such as that used for steaks, where the meat is held above a surface which has many holes to allow draining.  One should be careful not to crowd the pieces together.


The meat should be broiled until it is done and ready for eating in a normal manner.  The absolute minimum is defined by the halakha as "half of the normal broiling" (Yore Deah 73,1), but one should normally leave it on the fire until "fully" broiled.  This is especially true if it will be cooked after the broiling. 


  1. The utensils


The blood that is being purged from the liver is itself, of course, prohibited.  Although this blood will not re-prohibit the liver itself, any utensil that comes in contact with it while hot will become unkosher, since it absorbs the blood.  Therefore, they cannot be used to cook or broil anything other than liver.  One must either "kasher" the utensil after use, or maintain a separate set of utensils for broiling liver.  The same is true for the oven itself, and therefore the dripping blood should be caught on a special pan or on silver foil.


If liver is kashered in an oven, there are opinions that require that the oven not be used for 24 hours afterwards for other foods.  Many poskim, however, do not think that the walls of the oven will absorb anything if there is no direct contact between them and drops of blood.  In any event, this is less of a problem in a broiler where the fire is above the meat.


For the same reason, one should not leave the liver on the spit or fork to cool, because we fear that at some point it will begin to reabsorb blood.  As soon as it is ready, it should be removed and washed off.


  1. Gelatin


We are now ready to begin the laws of kitchens.  Before that, we have one point to clarify.  In all the future shiurim, we will assume that we know what kosher and non-kosher ingredients are, based on the principles discussed in previous shiurim.  There is one case though that we should clarify now - the problem of gelatin.


Gelatin is the most well known of a series of problems, all of which derive from modern food technology.  There are all sorts of special ingredients added to processed foods, and many of them are of animal origin.  Depending on the procedure, there is some question whether they can be permitted.  Gelatin is an example that illustrates many of the questions.


Gelatin is produced from the skin and bones of animals.  If the animal is not kosher (either a non-kosher species, or if it is not slaughtered properly), it should follow that the gelatin is not kosher either.  Nonetheless, a number of authorities, most prominently Rav Chaim Ozer Grozinsky, permitted it, based on the method of production.


In order to extract gelatin from the animal bone or skin, the material is soaked in acids, heated for a long period of time, and treated in other ways.  The result is a dry white powder with no particular taste.  The Talmud (Pesachim 21a) states that a foodstuff which is not fit to be eaten is no longer prohibited.  On this basis, pure gelatin should be permitted.


There are other factors on which the permissibility could be based as well.  There exists a disagreement among the poskim whether bones of a non-kosher animal are prohibited.  Some commentators suggested that perhaps we could distinguish between soft bones, which are the ones prohibited by the Rambam (Hilkhot Maakhalot Assurot 4,18) and hard ones, which would be permitted according to all.  This suggestion though is not universally agreed to.  In any event, most gelatin is not made from bones but from skin - usually pig skin.


The main question revolves around whether the fact that pure gelatin is not fit to be eaten should be taken into account once it has been added to a food, so that now it is in fact edible.  Rav Chaim Ozer claimed that once it has the status of "permitted," it will not revert to being prohibited even if it becomes edible again.  While it would appear that several authorities agreed with this claim (see Shach, 114,21), others disagree (for instance, the Chatam Sofer, YD 81).


Rav Moshe Feinstein argues that even if a non-edible substance which became edible again would remain permitted, gelatin is different, as the stages are all intermediate within one process.  The purpose of treating the gelatin is to produce a food in the end, and in such a case an intermediate stage is not significant. 


Rav Aharon Kotler added an argument that since the purpose of gelatin is not to be eaten, but it is used as a coagulant (maamid), the principle of inedible foods being permitted should not apply to it.  This is based on the fact that yeast is prohibited on Pesach (as a kind of chametz), even though yeast per se is inedible.  The reason is that yeast is not a food in the sense that it is eaten, but only as a special ingredient in causing bread to rise.  The same reasoning, Rav Kotler argued, should apply to gelatin.


For these reasons, in most localities, gelatin is not considered kosher.  If one sees a product that claims to have kosher gelatin, this refers to the leniency of Rav Chaim Ozer.  Theoretically, it is possible, of course, to produce gelatin from kosher animals, but this is apparently not practical.  A few years ago, work was started on producing gelatin from fish bones, but this has not yet become commercially viable.  There are also vegetable substitutes for gelatin, though less effective, such as agar-agar.


In Israel, the rabbanut gives a hekhsher to gelatin produced according the instructions of Rav Chaim Ozer.  It is usually marked in a manner indicating that is it based on a special kula.  "Mehadrin" supervision in Israel, as well as the national supervisions in the US, does not authorize gelatin.


Despite this, it is accepted that medicinal capsules, which are made of gelatin, are permitted if there is no non-gelatin equivalent.