To have the perfect soufflé you need to whisk the egg whites until they stand in peaks on the whisk. Tip the whites delicately on top of the mixture using a palette knife and mix quickly, place the mixture in a ramekin.
The oven must be very hot, about 200°C, so that heat will coagulate the proteins of whisked eggs. Meanwhile air bubbles – air incorporated during whisking – expand within the soufflé making steam evaporate.
When the proteins network is firm, it traps the gas within the mixture, so that the soufflé will rise as a leavened dough. Even a small breeze of cold air could make the soufflé collapse.
The air bubbles trapped in the egg whites expand upwards, the heat solidifies them and form a nice crusty top. At this point, the soufflé doesn’t collapse, even when the air at the bottom is cooler.