If we already gave 20% of our income for the year to tzedaka and then someone comes to the door to ask for money can we "borrow" from next year's maaser money to give to this person? Does it make a difference if they are asking for money for food vs. asking for money in general?
Answer
One may give money to tzeddaka and then repay oneself from ma'aser, although it is advisable to declare in advance that this is one's intention.
In this context there is no difference between donations for food or other charity requirements.