I have done it twice, with dried chili flakes.

First, we steeped various concentrations in water to try and find the right amount of heat. It won’t replace actual beer, and tastes like ass, but it’s a usable proxy. I tasted with friends with different heat tolerance and we found out that with the chilis we were using, 2g/l was the right amount.

Then we added the flakes at flameout and left them during fermentation.

The beer itself was great. It was a classic tripel, where the bell-peppery notes actually shone without taking front stage and played well with the sweetness. The heat was discreet as first, but there was a cumulative effect with every sip that made it seriously hot halfway down. It was amazing.

We tried to replicate it last year but it wasn’t as good or hot.