In case you thought preparing chestnuts for roasting or boiling was going to be a cakewalk, allow this wiseGEEK author to set you straight. Chestnuts need to be scored on one end to allow steam to escape and to avoid turning your romantic thoughts of roasting chestnuts on an open fire into a desperate escape from rapid gunfire. It's absolutely true that there is a tool for everything, and the proper tool for scoring and eventually peeling chestnuts is called, not surprisingly, a chestnut knife.
A chestnut knife has a standard size handle, very similar in size and weight as a standard paring knife. However, a chestnut knife's blade is much shorter than a paring knife and has a very distinctive curve. Essentially, a chestnut knife looks like a bird's curved talon attached to the handle of a paring knife. It's this curvature which gives the chestnut knife its unique appeal and function.
Let's assume you have already purchased a supply of raw chestnuts from Ye Olde Chestnut Shoppe. You may have noticed at the Olde Shoppe that chestnuts are sold in two sizes, large and small. The smaller of the two chestnut varieties does much better during a boiling process, while the larger sized chestnuts are ideal for roasting over an open fire or on a stove using a perforated chestnut roasting pan. If you're serious about roasting chestnuts at home, you'll want to invest in more than just a chestnut knife. The chestnut pan allows you to properly toast the chestnuts without turning them into inedible pieces of Christmas-related charcoal.
This is where the chestnut knife earns its right to be included in the cutlery family. One end of each chestnut must be scored with a X in order to allow the shell to burst open and release the steam which builds up as the chestnuts roast or boil. A standard paring knife might be able to perform the task, but its straight blade does not handle curves well. The curved blade of a chestnut knife can follow the contours of the chestnut and deliver unto you a perfectly good rendition of an x, or a + if you prefer addition to multiplication.
Once the chestnuts have been scored with the chestnut knife, it may be a good time to reflect on the fact you are not celebrating the holidays in a hospital emergency room. One of the drawbacks of a chestnut knife is a tendency to slip during the scoring process. When scoring chestnuts with any kind of knife, use extreme caution and consider wearing a protective cutting glove on the hand holding the chestnut.
Roasting chestnuts is often more art than science, since the shell of the chestnuts must become charred but not burnt. The chestnut should pop open after a few minutes of judicious tossing in a roasting basket or chestnut pan. At this point, the chestnut knife can be used to peel away the charred coating from the delectable innards. Apply butter and salt to the roasted chestnut flesh and enjoy. The playing of Mel Torme's ode to chestnut roasting, otherwise known as the Christmas Song, is completely optional.