BnB generally have around 6 month life, some more some less depends on brand. I have yet to see one that isn't stores in a back room with a temp of less than about 80 degrees. I would assume that anything above 27degrees would be sufficent as soda begins to freeze at that temp (at least that is what they tell us at work) but being it doesn't have much if any water in it that temp could be quite a bit lower. the syrup in BnB is really nothing more than a thick soda. It has pretty much the same consistancy as soda just a little thicker. I would say that a good point of reference would be something like a "thin" brand of dish soap, not like syrup that many people associate it with.
If what you did yesterday still looks big, you haven't done much today.