A bread slicing guide is a kitchen tool which is intended to facilitate the slicing of even cuts of bread. It may be combined with a bread box as well, or used in a bread slicing machine. Some kitchen supply stores carry bread slicing guides, and they are also available through direct order. While not a vitally necessary piece of kitchen equipment, a bread slicing guide can certainly be handy, especially if you make a great deal of bread.
A typical bread slicing guide is usually box-shaped, with a series of slots along both sides. The slots act as knife guides, allowing you to insert a knife and quickly and evenly cut off a slice of bread. The slots are often at varying widths, to allow cooks to cut both thick and thin slices of breads. It is also not unusual to see a bread slicing guide built on a tilt, ensuring that the bread does not slide out while it is being handled. A serrated knife is ideal for cutting most types of bread, and you should be able to find one in any well equipped kitchen.
Both wood and plastic can be used to make a bread slicing guide. As a general rule, wood is untreated, so that it will not impact the flavor of hot breads, which can tend to absorb things like oils from wood. Wood tends to be more durable in the long term, since it holds up better to knife slips. A plastic bread slicing guide, on the other hand, can be easily thrown in the dishwasher to be cleaned.
In most cases, a bread slicing guide is designed to accommodate breads of varying widths. A bread slicing guide may even be adjustable, meaning that it can be manipulated to hug loaves of all sizes. Some bread slicing guides are bundled into bread boxes, allowing you to store bread in a convenient slicing guide, so that it is easy to cut off a slice when it is needed.
A related concept is a bread slicing machine, which is a device built specifically for cutting breads. A bread slicing machine has a series of blades, typically serrated, which vibrate when the machine is turned on. The cook gently forces a loaf of bread through the blades, which simultaneously cut the loaf into a set of even slices. In some cases, a bread slicing machine may be adjustable, so that the blades can be moved for slices of different thicknesses.