Archive for the 'Corn Mug FAQ' Category

Are the Mugs Microwave and Dishwasher Safe?

Question Posted by: Melanie on February 18, 2009 at 4:25 pm

Are the mugs dishwasher or microwave safe?

CornMug says:

Hi Melanie,

Good question. The mugs are indeed microwave safe but we recommend hand washing as most dishwashers reach extremely high temperatures for extended periods of time and can weaken the plastic or cause misshaping.

Although corn plastic naturally has a lower melting point then regular plastic, our thick walled corn mugs can withstand quite a bit of heat before being damaged. I have had good success with top rack dish washing, however I know of others with hotter dishwashers who have warped their mugs this way.

The corn plastic compound is made of 100% natural fermented cornstarch products with less than 1% non-toxic dye for coloring. If your mugs do become heat damaged, they are still safe to drink from once they have cooled.

Thank you for your question!


What type of plastic is the lid of the 17oz mug made of? What does surgical plastic mean?

Thank you Jaxon for this question!


100% Corn plastic was not suitable for the lids because we needed something flexible to create a good seal, yet highly resistant to heat. Corn plastic is only heat resistant in its thick walled, rigid form that we use for the mugs.

The plastic we use for the lids is called Hytrel. It is a food grade, flexible non-bio plastic that is used in many industrial, surgical, and food production applications. It is very durable and non leaching.

New in 2008, the manufacturer of Hytrel is moving toward greater sustainability by increasing the bio-plastics content of the Hytrel material.

Here is an article from DuPont on Hytrel’s move toward using bio-plastic content:

If you have any further questions, please do not hesitate to contact us!

Thanks and have a green day!

Corn Mug Frequently Asked Questions

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Thanks and have a green day!

-The Corn Mug Team