Coke is IR transparent

Some time ago i made a blog post explaining how to remove the IR filter from a webcam in order to turn the webcam into a IR camera, or at least NIR (Near Infra Red).
Link here to the original post:
turn-normal-webcam-into-ir-webcam

Now i recently came across something interesting. It turns out that Coke is actually IR transparent. It's rather mind boggeling how something so dark in color can look like water with a NIR camera.

Here are some photos:

In the background you can see the webcam feed, seeing the glass as transparrent

How a normal camera sees this glass

Taken with the modified web cam

Another one

You can see thru the whole Coke bottle