How do you turn apples into a delicious hard cider? Just ask Alejandro del Peral, a cidermaker from upstate New York. It takes blending suitable apples, adding the right yeast, and experimenting with sourness to get the cider exactly right. As he puts it, the process is “about 50 percent chemistry, and the other 50 percent is art.” For more cider science, check out “Hard Cider, Easy Sipping.”