What "extra hot" means on our scale
Extra hot starts at 350,000 Scoville units and has no ceiling. These are superhot sauces, built on peppers bred for heat rather than for the table, and they're meant to be used by the drop. Treated that way, the best of them still taste of something; treated like a medium sauce, any of them will take over the meal.
What's in the bottle
Carolina reaper leads, in about a third, then habanero and ghost pepper at a little under three in ten each, scorpion in a quarter and 7 Pot Primo in around one in seven. Habanero's job here is to fill out the flavor under a superhot that has little of its own. A few bottles add pepper extract, which is heat with no taste at all.
Flavor survives if the maker wants it to
Three quarters of these sauces list garlic, and lime, tomato, cumin and vinegar all turn up often. That's the difference between a bottle you'll finish and one that sits in the cupboard: something to taste in the moment before the burn.
How to use it
Half of these bottles name wings, then chili, tacos and pizza. Use a drop, or stir a small amount into a whole pot so the heat spreads evenly. Keep milk, yogurt or ice cream nearby rather than water, and wash your hands before touching your eyes.
Before you buy
Check the pepper list and the rating together. A reaper sauce with fruit and vinegar behind it is a very different bottle from a thin extract sauce, even when both sit in this band. If you're arriving from hot for the first time, pick one built on a flavor you already like (mango, mustard or garlic) so there's something familiar underneath.