סימן צח סעיף ג
תַּבְלִין שֶׁאִם יִטְחַן אוֹתָם קֹדֶם יוֹם טוֹב יָפִיגוּ טַעֲמָן, מֻתָּר לְדוּכָן בְּיוֹם טוֹב עַל יְדֵי שִׁנּוּי, כְּגוֹן שֶׁיַּטֶּה אֶת הַמַּכְתֶּשֶׁת לַצְּדָדִין אוֹ שֶׁיָּדוּךְ עַל הַשֻּׁלְחָן וְכַיּוֹצֵא בוֹ. וְכֵן תַּמְכָא (קריין) שֶׁגּוֹרְרִין אוֹתוֹ עַל הַמּוֹרַג (רִיבאייזען), לֹא יִגְרוֹר לְתוֹךְ קְעָרָה כְּדַרְכּוֹ בַחֹל, אֶלָּא עַל מַפָּה. וְקַאפֶע אֵין לִטְחוֹן בְּרֵיחַיִם, אֶלָּא יְדוּכוּ בִמְדוֹכָה וְעַל יְדֵי שִׁנּוּי. אֲבָל טוֹב יוֹתֵר לַעֲשׂוֹת הַכֹּל מֵעֶרֶב יוֹם טוֹב. וּדְבָרִים שֶׁאֵינָם מְפִיגִין טַעֲמָם, וַדַּאי צְרִיכִין לִזָּהֵר לְדוּכָן מֵעֶרֶב יוֹם טוֹב, אַךְ אִם שָׁכַח, יֵשׁ לְהַתִּיר גַּם כֵּן עַל יְדֵי שִׁנּוּי. וְכָל הַנִּזְכָּר, אֵינוֹ מֻתָּר אֶלָּא מַה שֶּׁהוּא צָרִיךְ לְאוֹתוֹ הַיּוֹם וְלֹא לְמָחָר. וְיֵשׁ לְהַחְמִיר, שֶׁלֹּא לַעֲשׂוֹת אֶלָּא מַה שֶּׁצָּרִיךְ לוֹ עַתָּה לְאוֹתָהּ סְעוּדָּה. וְגַם בְּדִיכַת מַצָּה, יֵשׁ לִזָּהֵר בָּזֶה.
Should spices that are ground before Yom Tov lose their flavor, [before Yom Tov,] they may be ground on Yom Tov, if done in an unconventional manner: such as inclining the mortar on its side,or by pounding them on the table, or similar unconventional procedures. Horseraddish that is grated on a (hand-)grater may not be grated into a dish as is usually done on weekdays, but onto a tablecloth.17Chayei Adam 83:3, Mishnah Berurah 504:19. You may not grind it in a grinding mill, even in an unusual manner, for it is an uvdah de’chol, which is forbidden, even in an unconventional fashion. (general rule of the Magein Avraham 504:7) You may not grind coffee with a grinder,18Not even in an unconventional manner. (Panim Meiros, Peri Megadim, M.Z. 504:1) but you may pound it with a mortar in an unconventional manner. It is best to prepare everything on the day before Yom Tov. Foods that do not lose their flavor, certainly should be crushed the day before Yom Tov,19This is a rabbinical ordinance, so that Yom Tov is not spent working in the kitchen. (Shulchan Aruch Harav 495:7) but if you forgot (to do it before), you are permitted to do it in an unconventional manner on Yom Tov. All that was mentioned is only permitted for as much as you need for that day, but not for the next day, and you should be stringent to prepare only as much as you need for that particular meal. When grinding matzoh,20The matzoh is made from ground flour, and you are permitted to grind something that was previously ground, even in the usual manner. (Mishnah Berurah 504:20) you should also be careful about this.21Not to grind more than you need for that meal.
תנא דבי אליהו כל השונה הלכות בכל יום מובטח לו שהוא בן העולם הבא שנאמר הליכות עולם לו אל תקרי הליכות אלא הלכות (נדה ע"ג.)