The question was asked in Halacha if it is permissible to place mint leaves into a Keli Sheni of hot water on Shabbat. A Keli Sheni is for example an urn that has in it hot water poured from the primary vessel that was used to heat the water. In Arabic, mint leaves are known as Na’na. They are raw leaves. So the question was asked if it is permissible to steep raw mint leaves in a Keli Sheni.
The Gemara in Masechet Shabbat, Daf 39 quotes a Mishna which says one is allowed to be ‘Madiach’ on foods that are raw going into Shabbat. What does ‘Madiach’ mean? So the Tosafot brought a few explanations. One explanation of the Tosafot says it would be permissible to pour onto that raw item from a Keli Sheni, but to place it into a Keli Sheni would be forbidden. This basis for this is that it may seem like cooking. A Keli Sheni is still somewhat hot and the mint leaf is raw, and therefore it would be forbidden to place the leaves into a Keli Sheni. This explanation and ruling is actually the opinion of many of the Acharonim. Among those who hold this way include; the Magen Avraham (Rav Avraham Avli ben Chaim HaLevi Gombiner 1633-1683), the Ga’on Rav Zalman S. Aurebach (1900-1995), the Chayei Adam (Rabbi Avraham Danzig1748-1820), and the Mishna Berura (Rabbi Israel Meir Kagan, The Chofetz Chaim (1838-1933) .
However, the Tosafot then bring another explanation and says it would actually be permissible not only to pour from a Keli Sheni onto the raw item, but it is even permissible to put the leaves into a Keli Sheni. They say this because of our rule by Keli Sheni, which is that Keli Sheni can not cook. Therefore, there would be no problem of it looking like it is cooking. That opinion is taken by Chacham Ovadia Yoseph in his Sefer Yichaave Daat, Helek 6, Teshuva 22. So, Halacha Lema'ase, it is permissible to take mint leaves and place them into a Keli Sheni on Shabbat, even though they were not cooked from before Shabbat. This is based on the second answer of the Tosafot, that allows you to place raw items in a Keli Sheni.
