A pastry bag, also known as a piping bag, is used to pipe (extrude) semi-solid foods. Pastry bags are often coupled with piping tips or nozzles, which shape the extruded material. This is generally a matter of aesthetics, most famously cake decoration. Aside from icing, pastry bags are commonly used to shape meringue and whipped cream, and to fill donuts with jelly or custard. When presentation is especially important, fluted tips can be used to shape savory foods such as filling for deviled egg, whipped butter, and mashed potatoes.
Many foods (including frosting and pressurized "spray can" whipped cream) can be purchased in disposable packaging designed to serve the function of a pastry bag.
Pastry bags can be either reusable or disposable. High-quality, reusable pastry bags are often made from waterproofed cloth. Disposable bags are typically made of food-grade plastic. Both can be coupled with reusable piping tips—when using disposable bags, the tip is simply removed before discarding the bag.
A simple pastry bag can be made by rolling cooking parchment or wax paper into a cone, filling it, folding the wide end several times to close it, and then cutting the tip into whatever shape is desired. This is especially useful for small quantities of melted chocolate, since a very small hole can be cut and the bag can be discarded when it cools and becomes clogged.
Tips and nozzles edit
Piping tips are cone-shaped, with a base too large to fit through the small opening in the bag; they are to be inserted through the larger opening before food is spooned in. Many types of piping tip are available, coming in an array of shapes and materials. Tips are typically made of stainless steel, chrome-plated metal, or food-grade plastic. Circular nozzles are quite useful for making round shapes. The tip shown in the far left of the photo is a hypodermic-shaped one for filling pastries such as cream puffs, and many other types of nozzle are available for making star, leaf, and flower-petal shapes.
Tips may be inserted directly into the pastry bag or used with a coupler. Use of a coupler allows the chef to change the tip without needing to empty and refill the bag.
How to use edit
Once the proper tip is installed, fill the bag through the end with the wider opening, roll or twist it closed, and then squeeze it like a tube of toothpaste (from the top down, keeping the lower portion bulged out) to pipe its contents.
An assortment of metal piping tips
A pastry bag fitted with a star tip being used to frost cupcakes
A reusable pastry bag fitted with a coupler and a star tip
A pastry bag fitted with a leaf tip is used to decorate a cupcake