1There are substances which, if food is covered with them to preserve its heat,1 will raise its temperature and contribute to its being cooked as fire does2 -e.g., zefet, manure, salt, lime, sand, grape skins, unprocessed wool,3 or grasses4 when the latter three are damp, even5 when this is due to their natural moistness. These entities are referred to as substances that increase heat.איֵשׁ דְּבָרִים שֶׁאִם טָמַן בָּהֶן הַתַּבְשִׁיל, הוּא מִתְחַמֵּם וּמוֹסִיפִין בְּבִשּׁוּלוֹ כְּעֵין הָאֵשׁ - כְּגוֹן זֶפֶת, וְזֶבֶל, וּמֶלַח, וְסִיד, וְחוֹל, אוֹ זוֹגִין וּמוֹכִין וַעֲשָׂבִים בִּזְמָן שֶׁשְּׁלָשְׁתָּן לַחִים וְאַפִלּוּ מֵחֲמַת עַצְמָן. וּדְבָרִים אֵלּוּ נִקְרָאִין 'דָּבָר הַמּוֹסִיף הֶבֶל'.
There are substances which, if food is covered with them to preserve its heat, will accomplish that objective alone. They will not contribute to the cooking process, but will merely prevent the food from cooling-e.g., grape skins, unprocessed fabrics, grass, when these are dry, garments, produce,6 pigeon feathers, carpenters' sawdust, thin chips from the combing of flax, pelts, and the shearings of wool. These entities are referred to as substances which preserve heat.7וְיֵשׁ דְּבָרִים שֶׁאִם טָמַן בָּהֶן הַתַּבְשִׁיל, יִשָּׁאֵר בַּחֲמִימוּתוֹ בִּלְבָד, וְאֵינָן מוֹסִיפִין לוֹ בִּשּׁוּל, אֶלָא מוֹנְעִין אוֹתוֹ מִלְּהִצְטַנֵּן - כְּגוֹן זוֹגִין וּמוֹכִין וַעֲשָׂבִים יְבֵשִׁין, וּכְסוּת, וּפֵרוֹת, וְכַנְפֵי יוֹנָה, וּנְעֹרֶת הַפִּשְׁתָּן, וְנָסֹרֶת חָרָשִׁים, וּשְׁלָחִין, וְגִזֵּי צֶמֶר. וּדְבָרִים אֵלּוּ נִקְרָאִין 'דָּבָר שֶׁאֵינוֹ מוֹסִיף הֶבֶל'.
2According to Scriptural Law, before nightfall, one would be allowed to cover food with substances that raise its temperature, and thus the food would be covered and its heat preserved on the Sabbath, for it is permitted to leave food cooking on a fire on the Sabbathבמִן הַדִּין הָיָה, שֶׁטּוֹמְנִין בְּדָבָר הַמּוֹסִיף הֶבֶל מִבְּעוֹד יוֹם, וְיִשָּׁאֵר הַתַּבְשִׁיל טָמוּן בַּשַּׁבָּת, שֶׁהֲרֵי מַשְׁהִין עַל גַּבֵּי הָאֵשׁ בַּשַּׁבָּת.
The Sages, however, enacted a decree forbidding covering food with substances that raise its temperature before nightfall,8 lest the pot boil on the Sabbath and it be necessary to uncover it until its boiling ceases. If one would then cover it again on the Sabbath, one would be covering food with a substance that increases its heat on the Sabbath, and this is forbidden.9אֲבָל אָסְרוּ חֲכָמִים לְהַטְמִין בְּדָבָר הַמּוֹסִיף הֶבֶל מִבְּעוֹד יוֹם;  גְּזֵרָה, שֶׁמָּא תִּרְתַּח הַקְּדֵרָה בַּשַּׁבָּת, וְיִצְטָרַךְ לְגַלּוֹתָהּ עַד שֶׁתָּנוּחַ הָרְתִיחָה, וְיַחְזֹר וִיכַסֶּה בַּשַּׁבָּת, וְנִמְצָא טוֹמֵן בְּדָבָר הַמּוֹסִיף הֶבֶל בַּשַּׁבָּת, שֶׁהוּא אָסוּר.
Accordingly, it is permitted to cover food with substances that increase its temperature beyn hash'mashot,10 since at that time most pots have already boiled, and they have cooled, so that they cease boiling. Since they have already ceased boiling, it is unlikely that they will boil again.לְפִיכָּךְ מֻתָּר לִטְמֹן בְּדָבָר הַמּוֹסִיף הֶבֶל בֵּין הַשְּׁמָשׁוֹת - שֶׁסְּתָם קְדֵרוֹת בֵּין הַשְּׁמָשׁוֹת, כְּבָר רָתְחוּ וְנָחוּ מִבִּעְבּוּעָן, וְכֵיוָן שֶׁנָּחוּ, שׁוּב אֵינָן רוֹתְחִין.
3Similarly, according to Scriptural Law, on the Sabbath itself, one would be allowed to cover food with substances that do not raise its temperature. The Sages, however, enacted a decree forbidding this, lest a person cover food with a mixture of ash and coals that has sparks of fire, and stir the coals.11גוְכֵן מִן הַדִּין הָיָה, לִטְמֹן הַתַּבְשִׁיל בְּדָבָר שֶׁאֵינוֹ מוֹסִיף הֶבֶל, בַּשַּׁבָּת עַצְמָהּ; אֲבָל אָסְרוּ חֲכָמִים דָּבָר זֶה - גְּזֵרָה שֶׁמָּא יַטְמִין בְּרֶמֶץ וְיִהְיֶה בּוֹ נִיצוֹצוֹת שֶׁל אֵשׁ, וְנִמְצָא חוֹתֶה בַּגֶּחָלִים.
As a safeguard against this,12 the Sages forbade covering food with any substance13 on the Sabbath, even when it will not raise the food's temperature.לְפִיכָּךְ אָסְרוּ לְהַטְמִין דָּבָר חַם בַּשַּׁבָּת, וְאַפִלּוּ בְּדָבָר שֶׁאֵינוֹ מוֹסִיף הֶבֶל.
4If one is unsure whether it is before or after nightfall,14 one may cover hot food.דסָפֵק חָשֵׁכָה סָפֵק לֹא חָשֵׁכָה - מֻתָּר לִטְמֹן אֶת דָּבָר חָם.
Similarly, it is permitted to cover cold food with a substance that will not raise its temperature, to prevent it from becoming colder or to remove its chill.וּמֻתָּר לִטְמֹן דָּבָר הַצּוֹנֵן בַּשַּׁבָּת, בְּדָבָר שֶׁאֵינוֹ מוֹסִיף כְּדֵי שֶׁלֹּא יִצְטַנַּן בְּיוֹתֵר, אוֹ כְּדֵי שֶׁתָּפוּג צִנָּתוֹ.
When hot food that was covered before the Sabbath becomes uncovered15 on the Sabbath,16 it may be covered again, since one is not increasing its temperature.חַמִּין שֶׁטְּמָנָן מֵעֶרֶב שַׁבָּת, וְנִתְגַּלּוּ בַּשַּׁבָּת - מֻתָּר לְכַסּוֹתָן, שֶׁהֲרֵי אֵינוֹ מוֹסִיף.
It is permitted to change the covering of food on the Sabbath-e.g., one may replace clothing with pigeon feathers or replace pigeon feathers with clothing.17וּמֻתָּר לְהַחְלִיף הַכִּסּוּי בַּשַּׁבָּת.  כֵּיצַד? נוֹטֵל כְּסוּת וּמַנִּיחַ כַּנְפֵי יוֹנָה, אוֹ נוֹטֵל כַּנְפֵי יוֹנָה וּמַנִּיחַ הַכְּסוּת.
5Should one transfer hot food or water from the vessel in which it was cooked18 into another vessel, it is permitted to cover the second vessel with a substance that does not raise its temperature on the Sabbath, as one is permitted to cover cold food.19הפִּנָּה הַתַּבְשִׁיל אוֹ הַמַּיִם הַחַמִּין, מִכְּלִי לִכְלִי אַחֵר - מֻתָּר לְהַטְמִין הַכְּלִי הָאַחֵר בַּשַּׁבָּת בְּדָבָר שֶׁאֵינוֹ מוֹסִיף, כְּמוֹ הַדָּבָר הַצּוֹנֵן.
The prohibition against covering food on the Sabbath applies only to hot food in the vessel in which it was cooked. If it was transferred, it is permitted.20שֶׁלֹּא אָסְרוּ לְהַטְמִין בַּשַּׁבָּת, אֶלָא דָּבָר חַם שֶׁהוּא בִּכְלִי רִאשׁוֹן שֶׁנִּתְבַּשֵּׁל בּוֹ; אֲבָל אִם פִּנָּהוּ, מֻתָּר.
6One may place one metal pot on another metal pot, an earthenware pot on another earthenware pot,21 an earthenware pot on a metal pot, and a metal pot on an earthenware pot, and one may seal either an earthenware pot or a metal pot closed with dough-one's intent being not that they should be heated more, but that their heat should be preserved.22 The Sages forbade only covering food with other substances on the Sabbath. It is, however, permissible to place one vessel on another vessel so that they remain hot.23ומַנִּיחִין מֵחָם עַל גַּבֵּי מֵחָם בַּשַּׁבָּת, וּקְדֵרָה עַל גַּבֵּי קְדֵרָה, וּקְדֵרָה עַל גַּבֵּי מֵחָם, וּמֵחָם עַל גַּבֵּי קְדֵרָה, וְטָח פִּיהֶם בְּבָצֵק; לֹא בִּשְׁבִיל שֶׁיֵּחַמּוּ, אֶלָא בִּשְׁבִיל שֶׁיַּעַמְדוּ עַל חֻמָּם - שֶׁלֹּא אָסְרוּ אֶלָא לְהַטְמִין בַּשַּׁבָּת; אֲבָל לְהַנִּיחַ כְּלִי חַם עַל גַּבֵּי כְּלִי חַם, כְּדֵי שֶׁיִּהְיוּ עוֹמְדִין בַּחֲמִימוּתָן - מֻתָּר.
In contrast, we may not place a vessel containing a cold substance on a hot vessel on the Sabbath, for by doing so one introduces heat to it.24 It is permissible, however, to place cold food on a hot pot before the Sabbath commences.25 It is not considered analogous to covering food with a substance that raises its temperature.26אֲבָל אֵין מַנִּיחִין כְּלִי שֶׁיֵּשׁ בּוֹ דָּבָר צוֹנֵן, עַל גַּבֵּי כְּלִי חַם, בַּשַּׁבָּת - שֶׁהֲרֵי מוֹלִיד בּוֹ חֹם בַּשַּׁבָּת; וְאִם הִנִּיחוֹ, מִבָּעֶרֶב - מֻתָּר, וְאֵינוֹ כְּטוֹמֵן בְּדָבָר הַמּוֹסִיף.