One-Page Learn · The Halachos at a glance
כֵּלִים
Vessels 15-17
Sefer Taharah · When an oven becomes an oven and why even an accidental fire finishes it, how much may break away before it stops being one, and exactly where its edges fall
4
Handbreadths of a large oven that must remain for it still to be an oven, below which even an impure one is pure
3
Pieces an impure oven is broken into, with the clay coating stripped from each, the only remedy earthenware has
0
Ways a stone oven can ever be defiled, since Scripture orders an impure oven smashed and these laws reach only what can be smashed
1
Handbreadth a stone may protrude from an oven and still count as part of it, or three fingerbreadths from a range
Ch 15The fire that finishes, and the fire that does not
- Finished means fired. An earthenware container is not susceptible to impurity until the work of making it is complete, and completion is firing in a kiln: an oven when it has been heated enough to bake doughnuts, a range with two openings when a stirred egg could be baked over it in a frying pan, a range with one opening by the measure of whichever use it was built for. (15:1, 15:2)
- An accident finishes it; the wrong work does not. An oven heated from behind, heated in the craftsman's shop, or heated unintentionally is susceptible, and a court so ruled when fire broke out in an oven in a village, yet an oven heated to whiten bundles of flax stays pure because that work does not affect the substance of the oven. (15:3, 15:4)
- Stone never, metal on its own terms. A stone oven or range is always pure, and a metal one is pure under the laws of ovens, since Scripture says an impure oven must be smashed and these laws reach only what can be smashed, though metal is susceptible as metal is, by outside contact rather than inner space, and it can be immersed. (15:6)
- Clay makes it an oven again. A perforated or cracked metal oven patched with clay, or given a clay coating or upper surface, contracts impurity as earthenware does if the hole is large enough for fire to emerge, and clay pot rests make a metal range an earthenware one, while clay merely smeared on a metal range changes nothing. (15:7)
- No address required. An earthenware oven is susceptible even when it is not fixed to the ground, even hanging from the neck of a camel, since the verse says they are impure wherever they are, while a furnace for lime, glass or pottery is pure unless it has a place where a pot can be set. (15:8, 15:9, 15:10)
RememberThe fire that makes an oven usable is the same fire that makes it ruinable. Stone is exempt only because it cannot break.
Ch 16How much may break, and how a broken one comes back
- What counts as remnants. A large oven remains an oven while four handbreadths stand and a small one while its larger portion stands, so a large impure oven smashed below four handbreadths becomes pure, and the remnants of a range with two openings are three handbreadths. (16:1)
- Breaking is the only remedy. An owner who will not destroy an impure oven restores it by dividing it into three and removing the coating so each shard stands bare on the ground, while a break into two leaves the larger piece impure, and two equal pieces are both impure because it is impossible to determine which is larger. (16:2, 16:3)
- Rings, sand and a coating. An oven cut into rings with sand between them and coated with clay on the outside is susceptible, but where the coating itself was separated from the substance of the oven by sand or pebbles it never becomes susceptible at all, and of that oven it was said that a nidah and a pure woman may both bake in it and everything stays pure. (16:3, 16:5)
- Once exempt, exempt for good. Shards stuck together and coated inside and out and then heated make a susceptible oven though no shard is of the required size, while a large barrel whose base was removed and whose outside was coated stays pure, because earthenware once classified as not susceptible never becomes susceptible unless made into an oven and coated within and without. (16:7, 16:8)
- You cannot patch with the wrong material. Cracks filled with clay, lime or gypsum make the oven susceptible again, while a paste of ground earthenware, tar, sulfur, beeswax, yeast, dough or animal turds leaves it pure, on the principle that nothing an oven is not usually made from is sufficient to patch it, and a crack in a corner stays pure even when smeared at the sides. (16:9, 16:10)
RememberEarthenware has no mikveh. The only road back for an impure oven is to be taken apart and stripped of its coating.
Ch 17Where the oven ends
- An accessory is the vessel, if it is needed. Whatever a vessel requires in order to be used contracts impurity with it and whatever is not required stays pure, so a stone protruding a handbreadth from an oven or three fingerbreadths from a range with two openings is connected, and food or liquid touching it beyond that measure is pure. (17:1, 17:2)
- The same clay, two trades. The extra layer of earth on a homeowner's oven is pure while the identical layer on a baker's oven is susceptible, because the baker rests his spit on it, and an addition built around the pot of those who cook olives is impure while a dyer's is pure. (17:3)
- The crown and the tira. The crown of a range is pure, and the tira of an oven, the ledge where a loaf is set down as it comes out, contracts impurity with the oven when it is four handbreadths high and is pure when it is lower, since below that measure it is simply not connected. (17:4)
- Joined only by decree, and held in abeyance. The place at a range's side for a cruse of oil, for spices or for a lamp contracts impurity when the range is touched by a source of impurity but not when impurity is in its inner space, because it is joined only Rabbinically, and the Sages drew that line so that terumah and sacrificial food would be held in abeyance rather than burnt. (17:5)
- Measured borders, lightly held. The open space before a range is joined to it when raised three fingerbreadths and not joined at all when flat and without a border, trivets and protrusions are reckoned by the same three fingerbreadths from the ground and from the rim, and the Rambam closes by saying that these measurements are not held with great exactitude, being all of Rabbinic origin. (17:6, 17:7)
RememberNothing about the clay decides the border. What decides it is whether anybody actually leans on it.