A man in Taiwan had his kidneys severely damaged due to his habit of drinking coffee he brewed from stale beans every day.
He thought that by simply boiling the beans in hot water would make it safe to consume but was proven wrong.
Drank coffee each day
The unusual incident was shared in a Facebook post by Dr. Hung Yung-Hsiang, a nephrologist at a Taipei hospital.
Hung said that the man, 50-year-old Lee, was one who practiced a healthy lifestyle by going on morning runs and refrained from consuming alcohol.
The only beverage he drank daily was black coffee, which he would brew using coffee beans he bought at discounted prices.
Warning signs
Towards the end of 2025, Lee observed that his urine had more foam than usual and that both of his ankles were swollen.
He initially brushed it off as symptoms of over-exercising, but it proved to be otherwise when he suddenly lost consciousness while on his morning run.
At the hospital, tests showed that Lee’s estimated glomerular filtration rate (eGFR) levels were below 10 — a clear diagnosis of stage 5 kidney disease.
Stale coffee beans found to be culprit
At first, Hung was confused as to how Lee, a healthy individual who suffered no medical conditions, could end up having severe kidney problems.
He later found out that stale coffee beans were the cause after Lee revealed that he had been using the beans to make coffee as he felt it was a waste to throw them away.
According to Hung, stale coffee beans may contain a toxin called Ochratoxin A, which are naturally produced by certain moulds.
While often found in cereals, Ochratoxin A can also be found in coffee, beer, wine, nuts and raisins.
It also doesn’t decompose easily in high temperatures and can still be found in final food products that are sold to the public.
Hung added that Lee thought boiling the stale coffee beans in boiling water would solve the problem, but that wasn’t the case.
This is because Ochratoxin A targets the kidney and only breaks down at temperatures above 280°C, which is way higher than water’s boiling point of 100°C.
Hung reminded the public that they should always consume fresh food to prevent future health problems and warned against stockpiling food just to save up extra money.
He also said that the best way to store opened bags of produce like coffee beans by putting them into a fridge in sealed containers.
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