Alcohol's Also a Solvent, Absorbing Some of the Moisture from That (Sorry) Mucosa and Causing a Drying Sensation That Can Also Present Itself as a Burning...
Alcohol's also a solvent, absorbing some of the moisture from that (sorry) mucosa and causing a drying sensation that can also present itself as a burning feeling. But that only covers the mouth and throat—the heat that spikes the roof of your mouth and back of your gullet as some bourbon slips down into the esophagus.
Why does bourbon burn your throat?
When you drink whiskey with high concentrations of alcohol, it may lead to the drying up of that mucus membrane, resulting in a burning sensation in your mouth and throat. When this happens, you may crave water or another soft drink, in an attempt to rehydrate the mouth.
As the whiskey cascades down your throat, the signals released by these nerves hit your brain. Despite the whiskey being room temperature, your brain understands the signals as a fiery warmth sinking down your throat. Your eyes water from the heat.