Earthware and Earthenware

This week, the parsha reading in Eretz Yisroel is Chukas, and in chutz la’aretz, Korach. Since the earth is a major player in both parshiyos, I present:

Earthware and Earthenware

potteryQuestion #1: How is Earthenware Different?

In what ways are the laws of earthenware very different from other materials?

Question #2: Horseshoes, Hand Grenades and Hedgehogs

There is an old expression that “‘Almost’ counts only in horseshoes and hand grenades.” Why would someone add hedgehogs to this list, other than the fact that it also starts with the letter “h”?

Question #3: Inside, Outside

When does the halachah of something’s inside and its outside appear to be so radically different?


Moshe Rabbeinu davened to Hashem for the earth to perform a Kiddush Hashem and swallow up Korach and his entire entourage. It therefore behooves us to be makir tov, acknowledge the earth’s cooperation in fulfilling Hashem’s will, by studying some of the very unique halachos applicable to different types of wares manufactured from earthen materials.

Earthenware, also called pottery, figured very prominently in the ancient world. The clay used in manufacturing these vessels was readily available. From numerous discussions of the Mishnah (Keilim, Chapters 2-10), we see that earthenware was commonly used for pitchers, ovens, stoves, pots, dishes and other utensils. It is also interesting to note that much of our knowledge of ancient peoples is due to the widespread use of pottery. Since broken pieces of earthenware can last for millennia, archeologists glean much of their knowledge of early societies by studying the potsherds, or leftover broken pieces of earthenware, which survive for generations after wooden utensils have long decomposed.

In halachah, earthenware presents several atypical rules that are particularly significant to the laws of tumah and taharah (the rules of purity and spiritual contamination) and the laws of kashrus. Unfortunately, since we are all tamei today, we cannot apply the laws of tumah and taharah to the extent that we would like, but we fervently hope and pray to observe these laws again soon, when the Beis Hamikdash is restored and the purification of the parah adumah is reinstituted. This article will serve as a kind of primer so that we are better prepared to observe these laws. Let us begin with an introduction to the laws of tumah and taharah as they affect utensils, so that we can better understand the unusual status of earthenware.

Tumah and taharah

When explaining how the laws of tumah and taharah affect utensils, we categorize utensils according to the raw material from which they are manufactured. Halachah places most materials under two general headings:

1) Those that cannot become tamei, called keilim she’einam mekablim tumah.

2) Those that can become tamei and subsequently be made tahor again by immersion in a mikveh, called klei shetef, literally, utensils that can be immersed.

What we will see shortly is that earthenware vessels have their own unique halachic rules and fit under neither category.

  1. Utensils that cannot become tamei

Several types of utensils, including items made of stone or unfired earth (see Keilim 10:1; Ohalos 5:5), or of the bones or skin of birds (Keilim 17:14), fish or sea creatures (Keilim 17:13) cannot become tamei. I will henceforth refer to utensils in this category as non-contaminable utensils.

Kohanim at the time of Beis Hamikdash, who had many valid reasons to avoid tumah, often used bowls and plates made of stone, which is not susceptible to tumah. This information has been validated at archeological digs in Israel.

The following anecdote bears this out. A secular archeologist, well-educated in her profession, but, unfortunately, not sufficiently versed in the world of Torah, called a press conference in which she presented what she thought was a startling breakthrough. She “discovered” that a sect of people living in Jerusalem 2000 years ago was apparently cut off from the civilized world around them. While everyone else was using metal and earthenware utensils, these people were still living in the Stone Age, and used only stone vessels. Several religious members of the press burst out laughing, and the poor woman was at a loss to explain what was so funny. Finally, someone explained to her that the “sect” she was describing was composed of kohanim and others concerned about tumah and taharah, who were using only stone vessels that cannot become tamei.

  1. Utensils that become tahor in a mikveh

Most utensils and clothing made of natural materials, including those made of metal, leather, glass, animal bone, reeds, wood, cloth or other fibers, can potentially become tamei in a variety of ways.

Tumah hierarchy

The Mishnah, in the first chapter of Keilim, lists a “hierarchy” of ten sources of tumah, with a corpse rendering the highest level and a sheretz, the remains of one of the eight small creatures listed by the Torah in parshas Shemini (Vayikra 11:29-32), as the lowest. One of the general rules of tumah is that items that become tamei from a higher source of tumah become tamei in a greater way than items that become tamei from a lower level of tumah. For example, a vessel that becomes tamei from a corpse is significantly more tamei than if it became tamei from a sheretz. The two obvious manifestations of something being “more” tamei are:

More ways

(1) It contaminates more things in more ways. For example, a corpse, which is a high form of tumah, contaminates items (or people) through direct physical contact (by touch, called tumas maga), by being lifted by them (tumas masa), or by being under the same cover, roof or overhang (tumas ohel). Sheretz, a lesser form of tumah, contaminates items or people only through direct physical contact, but not via any of the other methods of contact.

More purifying processes

(2) Something that becomes tamei to a greater degree may require more processes and take a longer amount of time to make it tahor again. For example, to restore to tahor status a vessel that became tamei via contact with a corpse requires at least a seven-day procedure, including two sprinklings (on the third and seventh days) with spring water mixed with the ashes of the parah adumah, followed by immersion in a mikveh or spring and the onset of nightfall. Until its immersion, if it touches another utensil, the second utensil also becomes contaminated, and sometimes the second utensil can even contaminate a third utensil (Ohalos 1:1-3). According to some opinions, under certain circumstances, if the vessel that became tamei via contact with a corpse is in a room or house, it contaminates all utensils that are in the same room or house (Tosafos, Nazir 53b s.v. cherev).

On the other hand, a utensil that became tamei from a sheretz or other lesser degree of tumah can become completely tahor again in less than a day and, at times, within minutes, provided that one immersed it in a mikveh and waited until nightfall.

As I mentioned above, because these utensils become tahor after they are immersed, they are categorized as klei shetef, immersible utensils, which means utensils that can become tahor by submersion in a mikveh. I will henceforth refer to this category as immersible utensils. This includes utensils manufactured from the following materials: metal, leather, glass, animal bone, reeds, wood, cloth or other fibers.

Earthenware is different from all other wares

Whereas all other utensils fall under one of the above two categories (1) non-contaminable utensils or (2) immersible utensils, earthenware vessels have their own laws, different from both of the above categories. In general, earthenware vessels are susceptible to tumah, so they cannot be treated as non-contaminable utensils. On the other hand, although earthenware vessels are susceptible to tumah, they have very different rules than do immersible utensils. In some ways, the rules regarding earthenware are more lenient than those regarding immersible utensils, and sometimes the rules are more stringent. Earthenware truly marches to the beat of a different drummer. In what ways is it different?

Contaminate from outside

Immersible utensils become contaminated when they come in contact with a tamei source, whether they are touched on their internal surface or on their outside. This means that if something tamei touched the outer surface of a desk, bed or fork, the desk, bed or fork became tamei. However, if something tamei touched the outside of an earthenware vessel, it remains tahor. An earthenware vessel contracts tumah only from its inside, and only when it possesses an area that can service as a “container.” As a result, a flat earthenware board will not be able to become tamei, since it has no “inside,” nor will an earthenware fork, since it is not made to hold liquid.

Levels of tumah

Here is a second way that earthenware vessels are treated more leniently than are other utensils. Immersible utensils are susceptible to becoming tamei at a high level and also at a lower level. The higher level, called av hatumah (and sometimes even avi avos hatumah) makes other utensils and even people tamei, whereas the lower level (rishon latumah) contaminates only foods and beverages, but does not affect people or other utensils. On the other hand, earthenware vessels are susceptible only to the lower type of tumah – they can only become a rishon latumah, contaminating foods and beverages – even if they became tamei from the highest levels of tumah. Therefore, if a corpse or part of a corpse touched the inside of an earthenware vessel, it becomes a rishon latumah that can contaminate food or beverages. However, a tamei earthenware vessel that touches another utensil or a person does not render either of them tamei.

Earthenware is stricter

Until now, we have been studying areas in which the laws germane to earthenware vessels are more lenient that those of immersible utensils. Now, we will discover two halachos in which earthenware vessels are treated more strictly than utensils manufactured from other materials.


Earthenware vessels have an unusual law. They become tamei and spread tumah from their inside airspace, even without direct contact. In other words, if a tamei item is dangled inside an earthenware vessel, the vessel becomes tamei, and it will contaminate, subsequently, any food or beverage that hangs inside it. (As we mentioned before, any tumah of an earthenware vessel contaminates only food and beverages. It never renders other utensils or people tamei.)

Horseshoes, Hand Grenades and Hedgehogs

At this point, we can answer one of our opening questions: There is an old expression that “‘Almost’ counts only in horseshoes and hand grenades.” Why would someone add hedgehogs to this list, other than the fact that it also starts with the letter “h”?

First let us appreciate the expression. “Almost” knocking down a pin in bowling does not add to your score, and “almost” waking up early enough to daven in shul means that the person davened at home. However, in the game of horseshoes, one scores points even if he does not throw a “ringer,” and throwing a hand grenade so that it explodes almost on target is usually a successful enough lob to accomplish one’s objective.

At this point, we can explain the similarity between “almost” touching an earthenware vessel from its inside and actually touching it. The laws of contaminating earthenware vessels are that one can make them tamei, even if one does not touch them, as long as the tamei item, such as a dead hedgehog, was inside the airspace of the earthenware vessel. Thus, dead hedgehogs share a common characteristic with horseshoes and hand grenades in that “almost” can sometimes be as effective as being right on the money.

Breaking of the vessels

There is another way in which the laws regarding earthenware vessels are stricter than those of immersible vessels. Once they become tamei, immersible vessels can all be made tahor again through immersion in a mikveh or spring, provided that the correct procedure is employed. If the level of tumah is light, all that is required is to immerse the tamei vessel in a spring or a mikveh and then wait until nightfall for it to become tahor again. If the level of tumah is greater, such as because it became tamei from a corpse (see Bamidbar 19:17-19), it requires additional procedures. For example, an immersible utensil that became tamei from a corpse is rendered tahor by sprinkling it with the ashes of the parah adumah according to a specific procedure, followed by immersion in a spring or mikveh.

On the other hand, earthenware vessels that become tamei have no solution for making them tahor other than breaking them in a way that renders them useless. Immersing them in a mikveh does not make them tahor, nor do any of the other procedures, such as sprinkling on them ashes of the parah adumah. (Min haTorah, breaking any utensil renders it tahor. However, because of a rabbinic injunction, some immersible utensils remain tamei after they are broken [Keilim 11:1]. Since this is not an issue germane to earthenware vessels, we will leave it for a different time.)

Earthware vs. Earthenware

Until this point in this article, we have been discussing the status of earthenware, or pottery, which means vessels that are made of clay and then fired in a kiln. However, there is a vast difference in halachah between items made from earth without being fired, which are called klei adamah, and earthenware, called klei cheres. One can make very inexpensive vessels and utensils from earth, without firing them. These klei adamah items are not susceptible to tumah at all. (They fall under the category of non-contaminable utensils.)


Having discovered the anomalous world of tumah and taharah that applies to earthenware vessels, we will no longer be surprised to discover that earthenware utensils, also, have unusual laws relevant to kashrus. The Gemara (Pesachim 30b; Avodah Zarah 33b-34a) quotes the following discussion:

They asked Mareimar, “Can you use [chometz-dik] vessels made of coated earthenware on Pesach?” We are not asking you about the green ones – those certainly cannot be used. We are asking you about the black ones and the white ones. Furthermore, we are not asking you about those vessels whose surfaces are cracked, since they, also, certainly cannot be used. We are asking you about the ones that have smooth surfaces…. He answered them that they do absorb and that they are prohibited to use on Pesach, since the Torah testified that food that is absorbed by the walls of an earthenware vessel cannot be removed.

Apparently, there were at least three types of clay used in the time of the Gemara for producing “coated” earthenware (green, black and white), something that we would probably call “overlaid” or “plated.” “Coated” earthenware means that a layer of a less porous material was overlaid onto the clay prior to firing it to become earthenware. There is a dispute among rishonim as to what type of coating the Gemara is referring: Rashi explains that the earthenware was coated with lead, whereas Rabbeinu Tam understands that it was a glass coating (Tosafos, Kesubos 107b s.v. hani; Tosafos, Avodah Zarah 33b s.v. kunya; also see Rashi there).

Absorption and earthenware

According to all opinions, the halachah is that once a non-coated earthenware pot was used to cook chometz or non-kosher food, one will never be able to fully remove the flavor that has been absorbed in its walls. The basis for this concept is taught to us by a gezeiras hakasuv, an inference of the Torah itself. This means that residue of the chometz or non-kosher food absorbs into the porous earthenware, and, once absorbed, it leaches out gradually, and cannot be fully removed by kashering. Anything cooked subsequently in that pot may contain chometz or a non-kosher product. The only way to remove all the prohibited substance is by placing the earthenware into a kiln where the heat is so great that it burns out the prohibited substance, until none of the absorbed product remains. (Some contemporary authorities contend that one can kasher earthenware today via the cleaning cycle of a self-cleaning oven. However, before doing this, I recommend checking with your posek or rav and also ascertaining whether running the self-cleaning cycle with something inside the oven invalidates the manufacturer’s warranty.)

Understanding the Gemara

The Gemara assumed that earthenware vessels cannot be kashered, but inquired as to whether it is possible to kasher them when they are plated with a material that can be kashered. At first, the Gemara suggests that it might make a difference what type of clay was used in the construction of the pottery — some are apparently more porous than others — and the Gemara felt that this might influence how absorbent the vessel is, even after it has been plated. Those vessels manufactured from the “green” type of clay were the most absorbent, and even the Gemara’s initial position assumed that this type of pottery would be problematic. The Gemara’s conclusion is that one cannot kasher any earthenware vessels for Pesach, even if they are overlaid, regardless of the type of clay used in the earthenware.


This article has served as an introduction to some of the basic rules that affect earthenware. We should always hope and pray that the food we eat and the utensils in which we prepare it fulfill all the halachos that the Torah commands us.