Took me 7 months to figure out why my creme brulee kept breaking, and it was the torch the whole time
So I've been running the pastry station at a spot in Portland for about two years now and my creme brulee has been all over the place. Some nights it would come out perfect, glassy top, nice crack, and other nights the sugar would just pool up and stay wet or the custard underneath would break and get grainy. I tried everything, swapped my cream brand twice, played with the oven temp, let the custards sit overnight instead of 4 hours, even changed the ramekins thinking maybe the size was throwing off my bake time. This went on for like 7 months and I was honestly embarrassed because its a basic dessert and I'm supposed to be the guy who knows this stuff. My sous finally watched me torch one to order and goes "your flame is way too high, you're cooking the custard through the top" and it hit me like a truck. I'd been using this cheap hardware store torch on full blast because it was fast, and all that heat was going straight through the sugar into the set custard. Dropped the flame to low, held it further back, took maybe 20 extra seconds per dish, and I haven't had a broken one since March. Has anyone else chased a problem for months only to find it was one dumb habit the whole time?
The torch is a suspect but the custard breaking underneath is not from the flame. Sugar sits on top of a set custard, and torching it for 20 extra seconds at low heat is not enough to push through and curdle the whole thing. What you were probably fighting is an unstable custard base that was on the edge already, so some nights it held and some nights it tipped over, and slowing down your torch just stopped you from overworking it. A grainy, broken custard means it was overcooked in the oven or the eggs got too hot, and no amount of flame control fixes that. The real test would be to torch one the old way, full blast, on a custard you are sure is perfectly set, and see if it actually breaks. If it does not, then the torch was never the problem and you changed two things at once and gave credit to the wrong one.