Apparently redheads are not as susceptible to the pain caused by capsaisin and are a lot more susceptible to cold. I don't know if I'd describe myself as a redhead, but I do have some strawberry blonde going on sometimes.
Himself cooks to the edge of his pain threshold which generally leaves me at the "mmmm... tasty" mark, but isn't what I would call hot or spicy, and he's no lighweight when it comes to peppery foods. At Thai places I have to convince them to ignore the caucasian complexion and almost beg them to take it to the five star level. I've ordered hot sauce that is 800,000 scoville units and use habanero and ghost pepper powder in my eggs in the morning (as well as in my fudge recipe).
All this time I figured my love of hot food (and my tolerance for it) was because my formative years were spent eating tabasco-laden foods (so laden because my dad was a heavy smoker and couldn't taste a thing), but maybe the root cause is actually, well, my roots.
2 years ago