Bryan here how it was explained to me and I was excited cause that was exally how I do it now.

Come up with a batch number system,,,,, easiest way is the date followed by a numerical number for example. First bottling of the day on march 12 2012 0312121. Second bottling of the day on march 12 2012 0312122.
Take that number and write it in a log book with how many containers in that batch. I was also told it is a good idea to write down the customers name and phone number associated with the container at time of sale so if there is a problem the process of tracking down where each individual container went is simple.

I use a P-touch lable that I make of a lable maker that laminates the lable as well with my name, address and grade of syrup along with a line that has B# on it and thats where I write it in with a fine tip sharpy.