Musannaf Ibn Abi Shaybah

Hazrat Sulaiman bin Musa narrates that the Messenger of Allah (peace be upon him) saw a man who was selling mixed wheat. He said to him, "Separate this from that, and separate that from this, then sell it however you wish and sell it however you wish. Surely, there is no adulteration in our religion."

Hazrat Ibn Abbas (may Allah be pleased with them both) was asked about a man who mixes barley with wheat and sells it; what is this like? He replied that there is no harm in it.

Hazrat Sha'bi was asked about this matter, and he declared it disliked (makruh).

Muhammad considered it undesirable for a person to mix superior and inferior grains together and sell them; however, if the quality of both is similar to each other, then there is no harm in it.

Hazrat Hammad was asked: If a person sells wheat mixed with barley, or wheat mixed with wheat of an inferior quality, what is the ruling? He declared it to be disliked (makruh).