Corn has a great deal of pectin, the carbohydrate glue that holds vegetables together. Pectin doesn’t break down until around 183°F / 84°C, so you need to cook at a minimum of that temperature for corn to tenderize at all. At this temperature, it takes about 30 minutes for corn to tenderize while still retaining a bright, fresh crunch. Leaving your corn in the bath longer is OK, so long as you don’t go much longer than 2 hours, after which is begins to get too soft and mealy.
NOTE: If adding aromatics to the bag, add them sparingly. A few sprigs of herbs or half a split dried chili should do.
J. Kenji López-Alt
J. Kenji López-Alt is the Managing Culinary Director of Serious Eats, author of the James Beard Award-nominated column The Food Lab, and a columnist for Cooking Light. He lives in San Francisco. A New York native, Kenji cut his cooking chops the old-fashioned way by working his way up through the ranks of some of Boston's finest restaurants. With an education in science and engineering and as a former Senior Editor at Cook's Illustrated and America's Test Kitchen, Kenji is fascinated by the ways in which understanding the science of every day cooking can help improve even simple foods. He earned a James Beard award for his first book, The Food Lab: Better Home Cooking Through Science, which he released in September 2016. It is available for purchase from Amazon and Barnes & Noble.