freezer would be ideal but fridge should work. crank down the temp if you can (set it on "colder"/"coldest"), and put it on the bottom of the fridge. move any fruit, or anything else that can be damaged by freezing, to the top of the fridge. you'll be boiling the snot out of it when you return, and it's only 3 days, so i wouldn't worry too much - but do your boil as soon as you return. i would recommend against keeping it in the fridge until the following weekend.
have a taste when you return. there is always a chance that it will have soured a little (certainly not as much as it would have outside the fridge). if you do detect sourness, modify your recipe accordingly...