Crash whilst brewing in 1.6

Put the summary of the bug you're having here

What I expected to happen was...:
Awkward potions should be turned into instant health potions.

What actually happened was...:
Game crashed.

Steps to Reproduce:
1. Put 3x water bottles in brewing stand.
2. Put 1x nether wart in brewing stand.
3. Notice that 2x patch of netherwart have grown to maturity, harvest and replant, place some in nearby chest.
4. Open brewing stand interface, wait for brewing to complete.
5. Add glistering melon to brewing stand.
6. Crash.