Can You Put Plastic in the Dishwasher?
The answer is: it depends. Many plastics are perfectly safe for the dishwasher, but using the wrong type or cycle can lead to warping, melting, or chemical leaching. Always check for the dishwasher-safe symbol on the item before placing it in the machine.
Understanding Plastic and Dishwashers: A Primer
Dishwashers offer incredible convenience, but their high temperatures and powerful detergents can be harsh on certain materials. Plastic, a ubiquitous material in modern kitchens, requires special consideration. To determine if a plastic item is dishwasher safe, it’s essential to understand the types of plastic involved and the factors that influence their behavior in a dishwasher.
Types of Plastic and Their Dishwasher Compatibility
Not all plastics are created equal. Their chemical composition dictates their heat resistance and overall durability. Here’s a breakdown:
- High-Density Polyethylene (HDPE): Typically used for milk jugs and detergent bottles, HDPE generally isn’t dishwasher safe due to its lower melting point.
- Low-Density Polyethylene (LDPE): Often found in plastic bags and squeeze bottles, LDPE is also generally not dishwasher safe.
- Polypropylene (PP): A more heat-resistant plastic, commonly used for food containers and yogurt cups. Some PP items are dishwasher safe, especially if marked accordingly.
- Polystyrene (PS): Found in disposable cups and cutlery, polystyrene is rarely dishwasher safe.
- Polyethylene Terephthalate (PET): Commonly used for water bottles and soda bottles, PET is not dishwasher safe and will likely warp in high heat.
- Tritan: A BPA-free plastic known for its durability and clarity. Most Tritan products are dishwasher safe, but it’s crucial to check the manufacturer’s instructions.
- Melamine: Though often marketed as plastic, melamine is a thermosetting plastic. While durable, it can crack or chip in the dishwasher. Generally, it’s best to avoid putting melamine in the dishwasher.
The Dishwasher-Safe Symbol: Your Best Friend
The easiest way to determine if a plastic item is dishwasher safe is to look for the dishwasher-safe symbol. This symbol usually depicts a glass or plates being sprayed with water inside a dishwasher. Some variations indicate whether the item is safe for the top rack only. Always heed the symbol’s instructions.
The Dishwashing Process and Potential Risks
The dishwasher’s cleaning cycle involves several factors that can impact plastic:
- High Temperatures: Water temperatures in dishwashers can reach 140°F (60°C) or higher, potentially softening or warping less heat-resistant plastics.
- Harsh Detergents: Dishwasher detergents are formulated to cut through grease and grime. These strong chemicals can degrade some plastics over time, leading to discoloration or clouding.
- Drying Cycle: The drying cycle uses heated air, further increasing the risk of warping or melting for vulnerable plastics.
- Mechanical Stress: The spray arms and jostling within the dishwasher can cause physical stress on plastic items, increasing the risk of cracking or breakage.
Optimizing Dishwasher Use for Plastic
Even if a plastic item is marked dishwasher safe, there are steps you can take to minimize the risk of damage:
- Top Rack Placement: The top rack is typically cooler than the bottom rack, making it a safer location for plastic items.
- Avoid Heated Drying: Opt for an air-dry setting to reduce the plastic’s exposure to high heat.
- Use a Gentler Cycle: Choose a delicate or economy cycle to minimize the water temperature and pressure.
- Proper Loading: Ensure plastic items are securely positioned to prevent them from falling and being damaged by the spray arms.
- Check Regularly: Inspect plastic items after each wash for signs of warping, cracking, or discoloration.
What Happens When Plastic Melts in the Dishwasher?
Melting plastic in the dishwasher is a frustrating, and potentially hazardous, situation. Besides the ruined item, melted plastic can adhere to dishwasher components, causing damage. It can also release harmful chemicals into the dishwasher environment. Immediately turn off and unplug the dishwasher. Allow the melted plastic to cool, and carefully remove as much as possible. Cleaning the dishwasher thoroughly with a specialized cleaner may be necessary. Avoid using the dishwasher again until it’s completely free of melted plastic.
Table: Plastic Types and Dishwasher Safety
| Plastic Type | Dishwasher Safe? (General) | Notes |
|---|---|---|
| HDPE | No | Low melting point |
| LDPE | No | Low melting point |
| PP | Sometimes | Check for dishwasher-safe symbol |
| PS | Rarely | Very low melting point |
| PET | No | Likely to warp |
| Tritan | Usually | Check manufacturer instructions |
| Melamine | Avoid | Can crack or chip |
Frequently Asked Questions (FAQs)
Is it safe to put baby bottles in the dishwasher?
It depends on the material. Many baby bottles are made from polypropylene (PP) or Tritan and are dishwasher safe, but always check the manufacturer’s instructions. Top rack placement is recommended to avoid high heat exposure.
Can I wash plastic cutting boards in the dishwasher?
Some plastic cutting boards are dishwasher safe, but high heat can warp them over time. If dishwasher safe, place on the top rack and consider a cooler cycle to prolong their lifespan.
Will the dishwasher fade the color of plastic containers?
Yes, prolonged exposure to harsh detergents and high temperatures can cause some plastics to fade or become discolored. Using a gentler cycle and avoiding overly harsh detergents can help minimize this effect.
Is it okay to wash plastic food storage containers with residue in the dishwasher?
While the dishwasher can remove food residue, stubborn stains might require pre-soaking. Consider rinsing the container beforehand to prevent clogging the dishwasher filter.
What should I do if I accidentally melted plastic in my dishwasher?
First, unplug the dishwasher. Allow the plastic to cool and harden. Carefully remove as much melted plastic as possible, using a scraper if necessary. Run an empty cycle with a dishwasher cleaner to remove any remaining residue.
Are all “BPA-free” plastics automatically dishwasher safe?
No, being BPA-free doesn’t guarantee dishwasher safety. BPA-free simply means the plastic doesn’t contain Bisphenol A. You still need to check for the dishwasher-safe symbol and follow the manufacturer’s recommendations.
Can I put plastic utensils in the dishwasher?
Some plastic utensils, especially those made from polypropylene, are dishwasher safe. However, cheaper plastic utensils may warp or melt. Always check for the symbol and place them in the utensil basket away from heating elements.
Does the age of the plastic affect its dishwasher safety?
Yes, older plastics can become brittle and more prone to cracking or warping in the dishwasher. Consider handwashing older plastic items to preserve their integrity.
What’s the best dishwasher cycle for plastic items?
The best cycle is typically a gentle or economy cycle with a lower temperature and reduced drying heat. This minimizes the risk of warping and damage.
Can I use a rinse aid with plastic items in the dishwasher?
Rinse aid can help prevent water spots on plastic, but be mindful of the ingredients. Some rinse aids contain harsh chemicals that could potentially degrade plastic over time. Check the product label and use sparingly.
Is it safe to wash my reusable plastic water bottles in the dishwasher?
It depends on the material. Tritan bottles are usually dishwasher safe, but PET bottles are not. Check the manufacturer’s instructions. If dishwasher safe, top rack placement is recommended.
How often should I replace my plastic food containers?
Even with proper care, plastic food containers can degrade over time. Look for signs of warping, cracking, discoloration, or lingering odors. Replace containers that show these signs or every few years to ensure food safety.