Question:
I read that a voluntary fast ends with tzais hacochavim (please confirm) but I couldn’t find the halacha for when it begins. Assuming that you took on the voluntary fast during minchah the day before, does the fast begin at alot hashachar the next morning? Also, if you stipulated the night before that you would eat and drink before alot hashachar on the voluntary fast day, may one do so? (I’m asking for guidance for an Ashkenazi if that matters)
Answer:
All voluntary fasts as well as most other public fasts (with the exception of Tisha Bav and Yom Kippur) start from alos hashachar – daybreak- (see O:CH 562), unless the person already went to sleep for the night. If however he stipulated that he still wants to eat before alos, he may do so. The Ashkenazi minhag is that it is permitted to drink even after going to sleep for the night, because people always want to drink and it is as if he stipulated that he still wants to drink.
Best wishes
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