Dishwasher With Built-In Food Disposer: How It Grinds Food

What a built-in food disposer does

A built-in food disposer, sometimes called a food grinder, is a grinding mechanism located in the sump, the recessed basin at the bottom of the dishwasher tub where wash water collects. It reduces food scraps that wash off dishes into fine particles. Because the particles are small, they can be carried out of the machine with the drain water instead of collecting in the tub.

The disposer works within the machine's water circulation system. Water is pumped through the spray arms and jets, and that same flow carries loosened food particles down to the sump. When particles reach the grinding mechanism, they are broken into a fine slurry that stays suspended in the wash water until the drain phase pushes it out.

How the grinding works during a wash cycle

During a wash cycle, the dishwasher circulates a small amount of water repeatedly. Each pass through the sump gives the grinder a chance to reduce any food particles that came off the dishes. By the time the machine drains, most solid material has been ground into particles small enough to pass through the drain.

Grinding is most effective with soft, moist scraps such as sauces, rice, egg, and small pieces of vegetable. Hard items, including bones, pits, and large seeds, are better placed in the trash. They are too tough for the grinder to reduce quickly and can slow the drain.

Filter systems versus built-in grinders

Not every dishwasher grinds food. Many use a filter system instead. In a filter-based machine, wash water passes through a mesh screen that captures food particles. Those particles remain in the filter until you remove and clean it. A dirty filter can reduce cleaning performance and cause odors. See the filter cleaning guide for how to keep a filter-based dishwasher working well.

A dishwasher with a built-in disposer avoids that routine because the grinder reduces particles so they wash away with the drain water. That is a convenience if you would rather not clean a filter on a regular schedule. Both approaches can clean well when the machine is used correctly.

What to scrape off before loading

ENERGY STAR's guidance is to scrape, not rinse. Rinsing dishes before loading increases the total water and energy used. Today's dishwashers and detergents are designed to handle food left on plates. If dishes sit overnight, the machine's rinse feature uses a fraction of the water needed to hand-rinse them.

Even with a built-in disposer, a quick scrape removes the large items that are slow to grind. Bones, pits, and fibrous scraps belong in the trash. Soft scraps, sauces, and crumbs are what the disposer is designed to handle, and keeping hard items out reduces wear on the grinding parts.

Water conservation is another reason to skip rinsing. EPA notes that less than 1 percent of Earth's water is available for human use. Every rinse avoided keeps more water in local supplies, and because a dishwasher uses about the same amount of water regardless of load size, it makes sense to run full loads.

What to look for when buying

When you shop, look for a model with a soil sensor. ENERGY STAR says an auto-sensing cycle uses the sensor to detect whether the water coming off the dishes is dirty or clean, which saves water and helps the load come out clean. A soil sensor pairs well with a built-in disposer: both reduce the effort you need to put in before loading.

Also check the wash cycle options. ENERGY STAR recommends choosing a dishwasher with several cycles so you can match the cycle to the load, such as a light cycle for lightly soiled dishes, an energy-saving wash, or the option to turn off heated dry. More cycle options give you control over how the machine handles food residue.

Consider the machine's size and type. ENERGY STAR defines a standard-capacity dishwasher as one that holds eight or more place settings plus six serving pieces, and a compact model as one that holds less. Under the current criteria, standard models may use up to 240 kWh per year and 3.2 gallons per cycle, while compact models may use up to 155 kWh per year and 2.0 gallons per cycle.

Decide which form fits your kitchen: a built-in model slides under the counter, a countertop unit sits on the counter, and a portable model connects when you need it. The grinding principle is the same, but the wash system and installation differ.

Keeping the disposer working

A built-in disposer benefits from simple habits. Load dishes without stacking large scraps on top of plates, and let the spray arms do the work of loosening food. Scrape only the obvious leftovers before loading, then trust the wash cycle to handle the rest.

When the dishwasher finishes, open the door and check the bottom for any unground items. If you find a pit or a piece of bone, remove it and put it in the trash. This keeps the grinding mechanism from struggling on the next cycle.

Periodic maintenance is mostly about the machine's other parts. Keep the spray arms clear, use the detergent type the manual recommends, and run a cleaning cycle if the dishwasher has one. A clean interior helps the grinder stay effective.

• Scrape bones and pits before loading.
• Run full loads to save water and energy.
• Use the rinse feature for dishes that wait overnight.
• Check the sump occasionally for items that did not grind.

What to pick for your use

Questions

Does a dishwasher food disposer replace a garbage disposal?

No. A dishwasher disposer grinds food that has washed off the dishes inside the dishwasher. A garbage disposal sits under the sink and grinds scraps you put down the drain before loading. They serve different points in the cleaning process.

Can I put bones in a dishwasher with a food disposer?

No. Bones, pits, and other hard items can dull or damage the grinding mechanism and may not break down enough to drain. Scrape those into the trash.

Do I still need to clean a filter if my dishwasher has a disposer?

Usually not the same filter type. A disposer reduces particles so they wash away, so you skip the routine mesh-screen cleaning. Some machines still have a small strainer or secondary filter; check the manual.

Does a built-in food disposer make the dishwasher louder?

Grinding adds some sound when it runs, but manufacturers design insulation and placement to keep noise low. If quiet operation matters, look for models with lower decibel ratings and check the decibel comparison guide.