It’s a small cookware design feature that’s puzzled us all — okay, maybe not all of us, but some. What’s up with those little holes in glass pot lids? Why are they there? What do they do?
On Dec. 25, 2023, a user on X posted a picture showing a meat thermometer fitting perfectly in the hole. The post went viral, gathering over 20 million views.
Can’t describe how dumb I feel not knowing before today that this hole in the crockpot is for a thermometer pic.twitter.com/aBkmhJudsj
— Joe Flateau 👨🏻💻 🏒🇺🇸 (@joeflateau) December 25, 2023
Users in the comments questioned that usage, and searching on the internet, Snopes found plenty of other explanations. Listings on retailers like Amazon referred to them a steam-vent hole. We also found claims that the hole prevented glass lids from rattling or shattering, or that it equalized the pressure between the inside of the pot and the outside, preventing the lid from physically popping up.
With a variety of theories in our back pocket, we figured the best place to start answering the question was by asking the people who make such lids. Snopes reached out to five cookware brands — Hamilton Beach, Crock Pot, Calphalon, OXO and Caraway. While Hamilton Beach and Crock Pot make slow cookers, we also queried companies that make stovetop cookware, since those lids also often feature a hole.
The answer? Almost all of the above, as it turns out. Newell Brands, the parent company of both Crock Pot and Calphalon, did not respond to a request for comment. Neither did Caraway. But both Hamilton Beach and OXO provided answers.
On an FAQ post, Hamilton Beach noted that the hole in the slow cooker lid “allows excess steam to escape to avoid build up.”
OXO customer service representative also told Snopes via phone call that the holes vented a bit of the steam out, adding that it prevented the pot lid from rattling and equalized air pressures between the inside of the pot and the outside of the pot.
With that said, Snopes could find no evidence suggesting that inserting a thermometer in the vent hole changed the quality of the food, or adversely affected the functioning of a slow cooker.
But we found two potential downsides: plugging the hole with a thermometer might make water boil over faster, and depending on the type of thermometer used, the reading of the food temperature could be inaccurate.