A Broken Double-Walled Ceramic Starbucks Cup Is A Gross Nightmare

Let's be real, not one of us can walk into a Starbucks without looking over all the reusable tumblers for sale. That being said, not everything about Starbucks' famous cups is sunshine, rainbows, and twin-tailed mermaids. One TikTok user recently burst our Starbucks bubble when she shared the insides of a double-walled ceramic cup. According to her video, she accidentally broke the cup and ended up feeling "thankful [she] did," as the break exposed mold growing between the cup's double walls.

In the caption of her video, she added that she found a "hairline crack" in the cup, presumably present before she broke it. Viewers theorized that water had seeped into the crack each time the cup was washed. However, many people reported similar things happening with their own Starbucks double-walled cups, so are we to believe that all of Starbucks' cups are cracked, or is something else going on here?

Something to keep in mind when buying a Starbucks reusable cup

If mold in a Starbucks cup had been an isolated incident, we could shrug it off as a fluke. That being said, countless TikTokers commented on the video that their own double-walled cups had broken to expose nasty insides. One TikTok user even claimed to have found "dead worms" in theirs, which is arguably worse than the moldy mess shown in the original TikTok post.


😳 after breaking it i did notice a hairline crack, be careful 🫣 #moldycup #starbucksmoldycup

♬ original sound – Chelsie Dahl

That being said, there is indeed a reason for Starbucks' double-walled cups — or any double-walled ceramic items, for that matter — to be particularly susceptible to trapping water and growing mold. According to a ceramics Subreddit, double-walled ceramics have to be made with pinholes for "heated air to escape during firing," or else the pottery explodes in the kiln. Unfortunately, these little pinholes can lead to hairline cracks further down the road as the item is used.

Upon discovering your Starbucks cup is cracked, it's probably best to throw it out, as you don't know how much mold has gotten inside, but there are a few ways to prevent mold damage. First, if you spot any of these firing pinholes, you can fill them with glue or epoxy to keep water out. Secondly, Starbucks' double-walled cups are hand-wash only, but you should clean the cups with a damp cloth rather than dunking them in the sink with your other dishes. Whatever you do, do not put double-walled cups or tumblers in the dishwasher.