Talmud - Shabbat 20b שבת כ׳ ב׳

on a similar note, Rav Kahana said: Reeds that one tied them into a bundle, require that most of them ignite. If one did not tie them into a bundle, they do not require that most of them ignite, in accordance with the statement of Rav Huna. However, seeds require that most of them ignite. And if he placed them in woven baskets, they do not require that most of them catch fire.

Rav Yosef taught a baraita: Four bonfires do not require that most of the flammable materials catch fire, as their materials burn easily once the fire takes hold of them. And they are: A bonfire of pitch, and of sulfur, and of dry cheese, and of fatty materials. And it was taught in a baraita: A bonfire of straw and one of rakings of wood gathered from the field also do not require that most of it catch fire.

Rabbi Yoḥanan said: Babylonian wood does not require that most of it catch fire. Rav Yosef the Babylonian objects: What is that wood that they use in Babylonia that burns so well? If you say that it refers to wood slivers used for burning and light, now that with regard to a wick, Ulla said that one who lights it for a Shabbat lamp must light most of what emerges from the vessel; is it necessary to mention with regard to wood slivers that most of them must be lit? Rather, Rav Yosef said: Certainly the reference is to the branch of a cedar tree. And Rami bar Abba said: The reference here is to a hyssop [zaza].

We shall return to you, Yiziot HaShabbat

This mishna cites a list of fuels and wicks that one may not use in kindling the Shabbat lights, either because their use might induce one to perform a prohibited labor on Shabbat or because they are not in keeping with the deference due Shabbat. The mishna begins by listing the materials that one may not use as wicks. That is followed by a list of the substances that one may not use as fuel.

MISHNA: With what may one light the Shabbat lamp, and with what may one not light it? With regard to types of prohibited wicks, one may light neither with cedar bast [lekhesh], nor with uncombed flax [ḥosen], nor with raw silk [kalakh], nor with willow bast [petilat ha’idan], nor with desert weed [petilat hamidbar], nor with green moss that is on the surface of the water. With regard to types of prohibited oils, one may light neither with pitch [zefet], nor with wax [sha’ava], nor with castor oil [shemen kik], nor with burnt oil [shemen sereifa], nor with fat from a sheep’s tail [alya], nor with tallow [ḥelev]. Naḥum the Mede says: One may light with boiled tallow. And the Rabbis say: Both tallow that was boiled and tallow that was not boiled, one may not light with them.

GEMARA: Most of the terms used in the mishna were not understood in Babylonia. Therefore, the Gemara translated and clarified them. We learned in the mishna that one may not light with lekhesh. The Gemara explains that lekhesh is the branch of the cedar tree. The Gemara asks: Isn’t the cedar mere wood? How would one fashion a wick out of wood? The Gemara answers: The mishna is referring to the woolly substance that is beneath its bark.

The mishna taught further that one may not light with ḥosen. Rav Yosef said: Ḥosen is tow, thin chaff that falls off the stalk of combed flax. Abaye said to him: Isn’t it written: “And the ḥason shall be as tow” (Isaiah 1:31)? By inference, ḥosen is not tow. Rather, Abaye said: Ḥosen is flax whose stalk was crushed but not yet combed. The threads in the stalk are still covered by a shell and therefore do not burn well.

And we also learned in the mishna that one may not light with kalakh. Shmuel said: I asked all seafarers, and they said to me that the present-day name of kalakh mentioned in the mishna is kulka. Rav Yitzḥak bar Ze’ira said: Kalakh is the cocoon of the silkworm [gushkera].

The Gemara relates that Ravin and Abaye were sitting before Rabbana Neḥemya, brother of the Exilarch. Ravin saw that Rabbana Neḥemya was wearing metaksa, a type of silk. Ravin said to Abaye: This is the kalakh that we learned in our mishna. Abaye said to him: We call it shira peranda.

The Gemara raises an objection from that which we learned: The shira’im, the kalakh, and the sirikin, different types of silk, all require ritual fringes. Apparently, shira’im and kalakh are different types of silk. This is a conclusive refutation of the statement of Ravin who identified kalakh with shira peranda. The Gemara responds: Indeed, it is a conclusive refutation. If you wish, say instead that shira is a distinct entity, and shira peranda is a distinct entity. Shira peranda is kalakh.

And we learned in the mishna that one may not light with petilat ha’idan. The Gemara explains that petilat ha’idan is willow, which does not burn well. The Gemara relates that Ravin and Abaye were walking in the valley of Tamrurita. They saw these willow trees. Ravin said to Abaye: This is the idan that we learned in the mishna. Abaye said to him: But this is mere wood. How would one fashion a wick from it? Ravin peeled the bark and showed him the wool-like substance between the bark and the tree. We also learned in the mishna: Nor with desert silk [petilat hamidbar]. That is the mullein plant, which does not burn well.

And we learned in the mishna that one may not use the green moss that is on the surface of the water to fashion a wick for lighting the Shabbat lamp. The Gemara asks: What is this green moss? If you say that it is the moss found on standing water, isn’t that moss brittle and therefore unfit material from which to fashion a wick? Rather, Rav Pappa said: It is referring to the moss that accumulates on ships, which is more pliable and when dried can be fashioned into a wick.

It was taught in a baraita: The Sages added to the list of prohibited wicks in the mishna those made of wool and hair as well. The Gemara remarks: And our tanna did not consider it necessary to enumerate these because it is virtually impossible to fashion wicks from these materials, as, when they burn, wool shrinks and hair is scorched. Consequently, they are unsuitable for use as wicks.

And we learned in the mishna that one may not use zefet or sha’ava as fuel in lighting the Shabbat lamp. The Gemara explains that zefet is pitch, and sha’ava is wax. It was taught in a baraita: Until this point, the word zefet, the mishna is dealing with disqualification of materials unfit for use as wicks, and from this point on it is dealing with disqualification of substances unfit for use as oils. The Gemara asks: Obviously, a wick cannot be made from pitch and similar materials. The Gemara answers: It was necessary for the mishna to mention wax, lest you say that it is also unfit for use as a coating for wicks, in the manner that wicks are usually made. Therefore, it teaches us that even though wax is unfit for use as oil, it is fit for use as coating for wicks.

Rami bar Avin said: Tar [itran] is the by-product of pitch. When wood is burned to extract pitch, a clearer liquid oozes out after the pitch, and that is tar. Similarly, wax is the by-product of honey.

Traduction : The William Davidson digital edition of the Koren Noé Talmud, with commentary by Rabbi Adin Even-Israel Steinsaltz.

Shabbat 20b explores rules for kindling bonfires and Shabbat lamps, detailing which materials ignite easily and require no full combustion threshold.