What do the esteemed scholars and honorable jurists of Islamic law say about the following matter: In our village, wheat, barley, and other grains are ground into flour using machines. The machine owner (mill operator) takes two or three seers (a traditional unit of weight) of wheat, barley, or grain as payment for the grinding service. Is it permissible according to Islamic Shari’ah for the machine owner to take his wage in this manner? Kindly provide a detailed answer with evidence of the Qur'an and Hadith.
If the mentioned method is mutually agreed upon or established by local custom, then taking a portion of the grain as payment before the grinding is permissible and valid according to Shariah.
کمافی الدرالمختار: (أو استأجر بغلا ليحمل طعامه ببعضه أو ثورا ليطحن بره ببعض دقيقه) فسدت في الكل؛ لأنه استأجره بجزء من عمله، والأصل في ذلك نهيه - صلى الله عليه وسلم - عن قفيز الطحان وقدمناه في بيع الوفاء.والحيلة أن يفرز الأجر أولا أو يسمي قفيزا بلا تعيين ثم يعطيه قفيزا منه فيجوز اھ(6/56)۔