Reduce the heat to medium and continue cooking and stirring until the liquid crystallizes and becomes sandy, which will take about 12 minutes. Soon after the “sand” has appeared, the sugar will begin to liquefy and caramelize. As you cook the nuts, remove the pan from the heat from time to time, to prevent the caramel from burning so that the nuts can cook. The nuts will begin to pop and you’ll begin to smell their toasty aroma, after about 12 minutes. Most, but not all, of the sugar will be melted.