Responsa for Moed Katan 26:10

מיתיבי הנודר מן הדגן אסור אף בפול המצרי יבש ומותר בלח ומותר באורז בחילקא וטרגיס וטיסני בשלמא למ"ד חדא לתרתי חדא לתלת וחדא לארבעה שפיר דנפקו להו מתורת דגן אלא למ"ד כונתא דגן מעליא הוא קשיא

tisana, one into four.<span class="x" onmousemove="('comment',' Greek ** four.');">¹⁸</span> When R'Dimi came [from Palestine] he said: [All these are] kuntha [spelt]. An objection was raised: Hilka, tragus and tisana are [considered as] 'tainted'<span class="x" onmousemove="('comment',' Literally (ritually) defiled, potentially or actually, by the grain being washed before the milling. Fruits, grain and vegetables are not subject to ritual defilement until washed or sprayed or have Purposely been left exposed to get damped by rain or dew. After that deliberate damping these take ritual defilement by contact with defiling objects. Cf. Lev. XI, 34. 37-38 with commentaries of Rashi and Nahmanides and B.M. 22a-b, (Sonc. ed. p. 138-9) .');">¹⁹</span>

Teshuvot Maharam