The air was so bitingly cold this Mardi Gras when a crew from Philly Beer Week arrived at Brasserie Dupont in Belgium to help make a special collaboration beer that everything about the day flashed in high relief — the furnace blaze of a fire jet torching the copper brew kettle, the sweetness of grains being freshly milled, the pungent aroma of peat smoke and toasted barley puffing into the gray winter sky above the malterie, not far from the brewery in Tourpes. To open a bottle of Spéciale Belge just three months later, then, is to discover the magical transformation time and yeast can work. The brew is a richer amber hue than the saison Dupont is most famous for. But the aromatic house yeast is still unmistakably present, in the pop of the bubbles, in the earthy notes of biscuit and black pepper, in the fruity tones (orange zest, apricot, and ginger spice) that circle the tongue before fading into a so-subtle after-puff of malty smoke. What was so boldly vivid on the day of creation has softened and transformed itself into something altogether more refined and complex. Even though I was there, every sip is still full of mystery.