Musnad Ahmad 1153:974

'Affan narrated to us, he said: Mahdi ibn Maymun narrated to us, he said: Abu 'Uthman al-Ansari narrated to us, he said: I heard al-Qasim ibn Muhammad ibn Abi Bakr narrating from 'Aishah, from the Prophet, may Allah bless him and grant him peace, that she heard him saying: "Every intoxicant is forbidden, and whatever causes intoxication by the *faraq* (a large measure), then a handful of it is forbidden."