Things You'll Need
Stiff brush (optional)
Pot or heatproof mixing bowl (optional)
Classes and instructional videos can quickly teach you how to create attractive borders and decorations on your cake, but -- oddly -- few go on to explain in detail how to clean your piping bag afterwards. Inadequately cleaned bags are unsanitary and potentially hazardous, so learning to clean them properly is an essential skill.
Squeeze any remaining contents from your bag, saving them for later if appropriate. Uncouple the tip from your bag and set it aside, then turn your bag completely inside out. Remove your coupler's inner ring and set that aside with the tip.
Run the bag under the hottest water your tap can manage short of scalding your hands, to dissolve and rinse away fat-based icings, whipped cream or fatty mousses. For choux paste or other flour-based batters, rinse under cold water instead.
Wash the bag thoroughly with hot, clean water and conventional dish soap. If your bag is the heavy-duty canvas type, scrub the canvas thoroughly with a stiff brush, both inside and out. Canvas bags are permeable, and fat will lodge in crevices of the fabric's mesh.
Clip the piping bag to the upper rack of your dishwasher, using a clothespin, and run it through a high-temperature wash cycle with your next load of dishes. The high-temperature cycle is hot enough to effectively sterilize the bag. If you don't have a dishwasher, put the bag in a clean pot or heatproof mixing bowl, and cover it with boiling water for at least 30 seconds before draining.
Hang the bag to air-dry thoroughly. Some have a loop at the wide end for this purpose, or you can attach a clothespin or stationery clip to the lip of the bag and hang it from a hook. Alternatively, stand the bag upright in your dish drainer overnight to dry.
Instead of rinsing the bag under hot water, some bakers prefer to put it in the freezer for 15 to 20 minutes. This hardens the icing or batter, which cracks and falls off readily if you then beat the bag against the sides of your sink. With the bulk of the icing removed, you can proceed to hand-wash your bag.
Heavy canvas bags take the longest to dry, up to a full 24 hours depending on your climate. Plastic-lined and nylon bags may require as little as an hour or two. Never put a bag away until it's thoroughly dry, or it could be susceptible to mold.
Wash your tips and couplers by hand, using a brush to extract any food debris from the coupler's threads. A conical brush can be useful for scouring the inside of your piping tips. Hand-dry the tips with a clean paper towel, then let them air-dry for an hour or two so any residual moisture can evaporate. Otherwise, your tips could become rusty on the inside once they're put away in storage.
If you have access to a food-grade sanitizer through your workplace, or can wheedle it periodically from a restaurant or bakery in your area, you can spray your bags with sanitizing solution rather than running them through your dishwasher or soaking them in boiling water. This prolongs the life of nylon and plastic-lined fabric bags.
To minimize cleanup, use plastic wrap to contain your icing and other piped foods. Lay out a sheet of plastic film wrap on your work surface and scoop your icing onto the middle of it. Fold the plastic tightly over your icing and roll it up like a sausage, twisting the ends of the plastic wrap to squeeze your icing into a tight cylinder. Place a coupler in your piping bag, then drop in the plastic-wrapped icing. Pull the twisted end of the plastic wrap through the open end of the bag and snip it off, so the icing can pass, and then attach a tip to your coupler. When you've finished piping, simply uncouple the tip and then shake out the plastic wrap and any remaining icing. There should be little or no icing adhering to the lip of the bag, so changing colors is as simple as popping in another roll of icing and coupling a fresh tip.
If you frequently use a piping bag for mousses containing meat or seafoods, keep a separate, marked bag for that purpose. This minimizes the risk of introducing bacteria from those foods into your icing or whipped cream.
Discard any rusted piping tips, or any bags that show signs of mold.