- The "Butterbeer" we see the students drinking in this film is actually a well known British fruit drink called J20, with fake foam added on top. However, an official "ButterBeer" is in the making for a planned Harry Potter theme park.
- The foam in Ron's mouth in one scene is made of egg white.
- Dan admitted he never tries to go for "real tears" in any such scenes, by advice he got from actor Kenneth Branagh. Instead he relies on acting and "tricks of the trade" to get the desired effect across.
- The strange "fluid" in Dumbledore's Pensive is entirely done with CG.
- That highly torturous fluid in the cave that Dumbledore drinks, this was really just some milk thinned down with water and then visually "tweaked" by the CG department.
- Barron commented that the film's director and the composer tried "for months" to create a specific "Phoenix song" score which they felt would do its book description justice, for the scene where this bird leaves Hogwarts. Several different things were composed and tested, before they pretty much gave up trying and settled on this very basic score we now hear at the end of the film.