What is it in sharp cheddar that tastes "sharp?"

I suppose that extra sharp cheddar is a little harder than mild cheddar, so it i aging and drying that makes it that way…and does that also just concentrate the flavor as water evaporates?

If so, what exactly is giving it that tangy sharpness?

Also, when I eat really sharp cheddar, I get a slight pain at the back of my jaw. Anyone else get that or know what it is? I guessed it was something hat reacts to the tangy element and stimulates the salivary gland in the area…or maybe reacting with the masseter…it kind of feels like it tightens a bit and a brief tingly pain.

Here’s a non answer, but it’s a start:

I always thought it was lactic acid, but that seems to obvious to be right.

It’s all in the cow buttholes.

Same assumption, but wanted confirmation…wasn’t sure if it might be something more fun!

Now that I think about it though, the pain in my jaw is pretty similar to the pain felt from lactic acid build up in muscles while exercising…just nowhere near as severe.

This patent abstract might be of interest.

More on cheese flavours here. I suspect that the chief “sharp” notes are a combination of lactic and propanoic (propionic) acid.

As for the pain, I sometimes get that when eating strong salt-and-vinegar flavour potato crisps. The acid seems to kick the salivary glands into action, causing a slight but sharp pain.

Edit: a Google Books result with lots on cheddar manufacture (scroll up a bit).