Keilim, Chapter 3, Mishnah 8. The mishnayot here have been dealing with a keli cheres, an earthenware utensil, that developed a hole large enough to remove it from the category of a usable vessel and thereby render it tahor. The halachah taught earlier is that if such a utensil is patched with tar, its status depends on what it is meant to hold: if it is designated only for cold food and liquid, the tar patch works and the utensil can once again become tamei, since it truly functions as a container. If it is intended for hot use as well, the patch is worthless, because heat will melt the tar away, and the utensil remains tahor. An earthenware barrel is a vessel used for cold contents, so a tar plug is fully effective in restoring it to the status of a complete keli. Our mishnah now turns to the plug itself: does the tar become part of the barrel for the purpose of transmitting tumah?
How Much of the Tar Counts as the Barrel?
The mishnah begins: "chavit shenikvah ve'asa'ah bezefet yater misorkah," a barrel that was pierced with a hole and the owner sealed it with more tar than the hole actually required. The barrel then contracted tumah. What happens to food or liquid that comes into contact with the tar?
Comes the ruling: "hanogea besorkah tamei." Food or liquid that comes up against the quantity of tar required for the sealing takes on tumah, since that measure has effectively been swallowed into the barrel and now carries the barrel's impurity along with it. Then the mishnah adds "yater misorkah tahor": touching the tar that goes past what the repair demanded leaves one tahor.
The principle is a clear one. Only that measure of tar which the vessel actually needs in order to function as a container is treated as part of the keli. Anything piled on beyond that is simply tar sitting on a barrel, and it has no share in the barrel's tumah. So when the barrel is impure, contact with the necessary portion of the plug conveys tumah, while contact with the excess does not.
Tar That Dripped Onto a Barrel
A second scenario follows, this time tar that arrived by accident. The mishnah's words are "zefet shenatfah al hachavit," tar that dripped down onto an earthenware barrel and hardened where it landed. Should the barrel later contract tumah, the ruling is "hanogea bah tahor": anything meeting that tar stays tahor. Nothing in the barrel's usefulness rests on this tar. It closes no breach and repairs no defect, and because it adds nothing to the way the vessel works, halachah does not count it as belonging to the barrel. The barrel's tumah therefore does not reach it.
The Funnel That Was Sealed With Tar
The mishnah now moves to a funnel, a mashpech. A funnel is wide at the top and narrow at the bottom, with an opening at its base so that whatever is poured in runs straight through from top to bottom. It is a conduit, not a container. But if someone seals that lower opening with tar, the object can now hold its contents, and the question becomes whether it has been transformed into a keli capable of receiving tumah.
In the mishnah's language: "mashpech shel eitz veshel cheres shepekako bezefet," a funnel of wood or of earthenware whose lower hole has been stopped up. The first opinion is that of Rabbi Elazar ben Azaryah, who rules "metamei": in his view the funnel is now susceptible to tumah. With the outlet blocked, the object no longer merely channels what is poured into it, it retains it, and something that retains its contents is a keli.
Rabbi Akiva divides the ruling according to the material. He is "metamei beshel eitz," a plugged wooden funnel is able to contract tumah, yet "umetaher beshel cheres," an earthenware one stays tahor and cannot become tamei at all. Behind the distinction lies a practical assessment: tar will not adhere dependably to earthenware, so the blockage cannot be trusted to hold. Lacking a real stopper, the earthenware funnel never becomes an object that actually retains its contents, and so it never becomes a keli. Wood is another matter. There the tar grips, the seal lasts, and the funnel qualifies as a receptacle.
The final view is that of Rabbi Yose, who rules "metaher bishneihem," treating wood and earthenware alike as tahor. To his mind tar is not a dependable stopper for either one, so in neither case has the funnel been turned into an object that genuinely holds what is poured into it.
The thread running through the entire mishnah is the same: tar acquires the status of the vessel only to the extent that the vessel genuinely depends on it. The tar needed to close a hole becomes part of the barrel; surplus tar and stray drippings do not. And whether tar can turn a funnel into a container at all depends on whether the seal it forms can truly be relied upon.