When whisking egg whites and sugar to make meringue mixtures it is best to whisk on medium or medium-high speed, NOT high. It will take a couple of minutes extra for you to create your meringue but the final mixture will be made up of tiny, even air bubbles – which is exactly what you are after! It will be smooth, thick, and glossy and have a shaving cream-like consistency which will give you a crisp meringue that won’t crack when baked. Meanwhile, a meringue whisked on high speed will end up with large, uneven air bubbles and a frothy consistency which will often rise and crack when baked. So, remember to whisk on medium, or if you are a little impatient, no higher than medium-high when making meringue.