It's impossible for humans to taste colours because taste and colour are completely separate senses.
While most people cannot taste colours, some individuals have synesthesia, a neurological condition where stimulation of one sense triggers sensations in another. Certain types of synesthesia cause specific tastes to be associated with colours. This is rare but documented, proving the strict separation of senses isn't absolute for everyone.
Reception
Sources
- Synesthesia - Wikipedia PRIMARY
- Snopes: Taste Colors REFERENCE