Sahih Bukhari
Drinks
Volume: 007 / Book Number: 069 / Hadith Number: 507
Narrated Abu Qatada:
The Prophet forbade the mixing of ripe and unripe dates and also the mixing of dates and raisins (for preparing a syrup) but the syrup of each kind of fruit should be prepared separately. ( One may have such drinks as long as it is fresh )