Beginners stare at the bubbles and get hypnotized. Pros watch the temperature like it’s a reality show finale. Boil hard until you’re within 3°F of your target, then drop the heat to a simmer. Those last degrees are where the gold lives.
If you’re using a propane burner outdoors (like I do), wind will mess with your readings. Shield your pot. Also, don’t leave the thermometer in the pot while it’s boiling—it’ll snap or give you a false high reading. I speak from burn-scar experience.
Look, finishing temperature isn’t poetry. It’s geometry with sugar molecules. But when you nail 219°F at sea level, the syrup turns that perfect amber, the kind you’d send in a love letter. Take it from me and my reformed friend Dave: the difference between “meh” and magic is seven tiny degrees.