Muhammad bin Sirin (may Allah have mercy on him) says that Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said: "We were commanded to pay the zakah of Ramadan on behalf of every young and old, free person and slave, as a sa' of food; whoever brings wheat, it should be accepted from him; whoever pays with barley, it should also be accepted from him; whoever pays with raisins, it should also be accepted from him; and whoever gives hulless barley (sult), it should also be accepted from him." I think he said: "Whoever gives flour or sawiq (roasted barley meal), it should also be accepted from him."
This too is mursal; Muhammad bin Sirin did not hear anything from Ibn Abbas, except that it agrees with the connected hadith of Abu Raja' al-Utaridi from Ibn Abbas, so it is more fitting that it be sound. As for what the narrator was in doubt about and which has no supporting report, it is not taken into account. And Allah knows best.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7714