Exchange of One Kind of Food Items for another Kind

9. Muhammad ibn Yahya has narrated from Muhammad ibn al-Husayn from Ali ibn al-Hakam from al-‘Ala’ from Muhammad ibn Muslim who has said the following: “I once asked abu Ja‘far عليه السلام, about his opinion on wheat and the sawiq (mush made of wheat or barley). He (the Imam) said, ‘Their exchange in equal measures is not harmful.’ I then asked, ‘What happens if one has a certain yield or preference over the other?’ He (the Imam) said, ‘Does it not have expenses and maintenance?’ I replied, ‘Yes, it has such overheads.’ He (the Imam) said, ‘This is for that.’ He (the Imam) then said, ‘If they are two different things then exchange of one for two at the same time is permissible.’”