system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why when you think or see very sour things, you start to salivate

I was watching a video of someone eating lots of warhead candies and I started to salivate, this has happened before, I was wondering why this happened?
gpt
A sour taste comes from acids in the food, so it may be a response to help protect tooth enamel from being destroyed by the acid.  This is why you salivate before vomiting, as well.  So your brain could be deciding you're about to eat something acidic, and pumps up salivary production in response?