Rambam Mezuza 12 CM on Klaf Meubad or Gevil
Klaf Meubad made according to Rambam
The method of making klaf parchment using “Afatzim” Oak Galls is the method that the Talmud (Megila 19a top of page) says that parchments need to be made for Sefer Torah’s, Tefillin, Mezuzot and Megilot. Today the standard method is to use Lime.
Ramba”m Maimonides states very clearly that klaf parchment must to be completed using “Afatzim” Oak Galls. He says
If they take the skin, after the fur has been removed and divide its thickness in half like the Leather tanners do, [dividing it] until they become tow skins. One [skin] is thin is the part closer to the fur, and one thick [skin] that is closer to the meat, They work salt into it, followed by Flour and afterwards with “Oak Gall” (Afatzim in Hebrew) and the like…. (Rambam halachot Tefilin, Mezuzah and Sefer Torah Ch 1 Halacha 7)
Today, many people have decided to follow the Rambam always, even if most Torah following Jews don’t. They feel that Klaf made with Sid – Lime is little better than paper, or just like writing on a raw, unprocessed piece of leather.
Mara”n Rabbi Yosef Karo in the Shulchan Aruch (O”H 32 – 8) states that you can use klaf parchment whether made with Lime (Sid) or “Afatzim” Oak Galls. He usually decided the halacha law according to Rambam, yet here he differs by Accepting the opinion of Rabenu Tam in the Tosafot ( Megila 19a)
Even those who believe that Klaf may be tanned with Lime accept that Afatzim – Oak Gall is Kosher.