At any given temperature, solid fats have different consistencies that depend on what fraction of their molecules is in solid crystals, and what fraction is liquid. Above about 25% solids, fat is too hard and brittle to roll into an even layer. Below about 15% solids, fat is too soft to work; it sticks to the dough, doesn’t hold its shape, and leaks liquid oil. The ideal fat for flaky and laminated pastries is therefore one that has between 15 and 25% solids at kitchen temperature, and at the temperatures that the pastry dough reaches as it’s mixed and formed. It turns out that butter has the right consistency for making pastry in a relatively narrow temperature range, between 58 and 68°F/15–20°C. Lard is properly workable at only slightly warmer temperatures, up to 75°F/25°C. Our flavorful natural fats easily get too soft in the kitchen to make good pastry. This is why pastry makers often prechill ingredients and utensils, work on a cold marble surface that keeps the ingredients cool during the mixing and rolling out, and value assistants with constitutionally cold hands.