What not to put in the dishwasher

Dishwashers are a labor saver. However even with the convenience there are several items that should not go in the dishwasher. This is a general guide as to what shouldn't go in the dishwasher. However, always refer to the manufacturers specifications if available.

Any wood

It may be tempting to just toss those wooden utensils in the dishwasher with all the other dirty dishes. However the long exposure to hot water may cause furring, ths is where the outside of the utensil starts to break down and the wood fibers loosen and create a fur like surface. In addition to being unsightly it provides a breading ground for bacteria. In addition the exposure to long and intense heat cycles can cause the utensil to warp and crack.

Travel Mugs and Similar containers

Most travel mugs and similar containers are double walled with a vacuum between the walls. This creates an insulating layer that keeps the contents nice and hot. However the long and intense heat cycles can break the seal of these containers allowing air between the layers thus greatly reducing the effectiveness of the container. Only put these in the dishwasher if labeled as dishwasher safe.

Cast Iron

Cast iron relies on a seasoned coating to achieve it's low stick surface. When run through a dishwasher this seasoning is stripped away necessitating a re seasoning.

Non stick pans

Non stick pans rely on a coating of no stick material in order to keep food from sticking. This coating is fragile and the material that it is made out of contain PFAS (per- and polyfluoroaklyl substances) some of which are known to be dangerous, and others are not fully understood. Overheating or abrading these materials can release these substances, so its best to wash these by hand gently according to manufacturers specifications.

Aluminum and Copper Items

Both copper and aluminum items can be discolored by a dishwasher. Only put these in if they are labeled as dishwasher safe.

Thin plastic Items

Items that are made with thin plastic shouldn't go into the dishwasher due to the risk of melting.

Chefs Knives

Chef's knives should generally not be put in the dishwasher for the risk of dulling, this is mostly due to items hitting the knife edge during the wash cycle. They also shouldn't go in if they have wooden handles for the reasons listed above. However some dishwashers have knife trays, which make washing these in the dishwasher ok.