How bad is it to boil instead of simmer?
Really Bad. A simmer consists of small yet constant pockets of bubbling and a few wisps of steam (roughly 180°F). A boil produces constant steam, with large bubbles quickly rising to the surface (212°F). Boiling destroys the protein in meat, drying it out. However, a boil followed by a cold rinse is best for colourful vegetables like green beans, which can fade when simmered. The takeaway? Closely follow the method the recipe calls for.