Why do the Heineken horses still go from the brewery to somewhere north???

If I am still home around 10AM (like I am right now….I am heading to work, really, I am) I always hear the Heineken horses clop by below my window. It happens every day. They go out around 10 and come back in the afternoon. There are no tourists on the cart, just about 10 kegs. But every day they go and come back. I have no idea why. I live on Utrechtsestraat fairly close to the Heineken brewery so if they want to head north, it would make sense that they pass me. I just don’t know where they go. Oh, and for you Americans reading this, the Heineken beer is a little bit better than the crap they sell in the US, but not a whole lot better.