"He came in a bit late on that Saturday saying he couldn't see properly," said Belgin, joint owner of the salon where he worked in the Ortakoy district, who didn't want to give her surname.
Not long after he got there, Erduan needed to sit down because he couldn't even hold a pair of scissors, she told AFP.
"He told us all he could see was whiteness so I immediately drove him to a private hospital," she said.
There, he saw an ophthalmologist who quickly realized it was a case of bootleg alcohol poisoning.
Erduan collapsed in late January, barely a week after the city was shaken by news that within just four days, 33 people had died and 29 were critically ill after drinking bootleg alcohol.
That number has since shot up to 70, with another 63 dead in the capital Ankara, Turkish media reports say. Another 36 remain in intensive care.
Erduan told the doctors he bought the vodka at a corner shop in Ortakoy, saying it was five times cheaper than the supermarket because it was imported from Bulgaria.
They gave him folic acid to try and stave off the effects of methanol, a toxic substance often found in bootleg alcohol that can cause blindness, liver damage and death.
"He was still perfectly conscious," his boss told AFP, her eyes red from crying.
Shortly afterwards, he was rushed into intensive care and intubated.
"On the fourth day, we went with his son to see him. He was totally yellow," she said, describing jaundice, another symptom of methanol poisoning.
"That evening, we heard he had died."
- 'Six hours to feel effects' -
"Nobody should have to die like that. The alcohol seemed totally legal from the packaging and the branding when in fact it came from an illegal distillery," said Erol Isik, her partner at the salon, who was clearly angry.
"Taskin didn't drink to get drunk, he wasn't an alcoholic," he said.
Speaking to AFP at his laboratory at Istanbul's Yeditepe University where he heads the toxicology department, professor Ahmet Aydin explained how lethal it can be.
"Just one glass of fake vodka made from methylated alcohol can be deadly," he said.
The difference between ethanol, which is used for making spirits, and methanol, which is used in varnishes and antifreeze, is only visible in a laboratory, he explained, showing test tubes containing the two alcohols.
"No-one can tell them apart by taste, sight or smell," he said.
"The biggest danger with methanol poisoning is that you don't feel the effects straight away. It only manifests after about six hours. If the person goes straight to hospital, they have a chance of recovering."
But it can very quickly become "too late".
"People really need to be careful," he warned, saying it was a lot easier to buy methanol than ethanol, the purchase of which is highly regulated.
"But who would drink alcohol without a proper label?" he wondered, following reports several people died after buying alcohol in half-litre water bottles from a business posing as a Turkmen restaurant in Istanbul.
– 'Alcohol is too expensive' –
Like the main opposition CHP party, Ozgur Aybas, head of the Tekel association of alcohol retailers, blames the crippling taxes imposed by the government of President Recep Tayyip Erdogan, who regularly rails against drinking and smoking.
"Nowhere else in the world are there such high taxes on alcohol," he told AFP, saying people had no choice but to seek out alternatives.
Buying a liter bottle of raki, Turkey's aniseed-flavored national liquor, from a supermarket currently costs around $35 in a country where the minimum wage is $600.
Standing in front of the now-closed shop where Taskin Erduan bought the vodka that killed him, a neighbor called Levent, who didn't give his surname, also blamed taxes.
"Alcohol is too expensive in Turkey. It costs about 100 Turkish lira to make a bottle of raki but with the tax, that becomes 1,200 lira," or the equivalent of 12-hours work at minimum wage, he raged.
Levent said he had long known the owner of the shop, describing him as "a nice guy".
But with Turkey in the grip of a severe economic crisis, he said he'd long since stopped being surprised at how far people would go to bring in a bit more cash.
"People will do anything for money. They have no shame any more."
© Agence France-Presse
