"If I forced one down my throat, I would literally throw up," says the restaurateur, who is chairman and owner of one of Singapore's most prominent chain of eateries and nightclubs, The Prive Group.
Then he read food critic Jeffrey Steingarten's The Man Who Ate Everything, which deals with the author's dislike of certain foods and how he overcame his biases.
For Steingarten, it was Greek and Indian food. For Mr Oeij, it was the pungent, slimey variety of raw shellfish.
Mr Oeij, like Steingarten, feels he has a duty to acquire a taste for all foods. Not just because of his job, but because he is passionate about food, he says.
"Whenever I was dining with people who were having oysters, I'd try them," says Mr Oeij, 48. After a while, he learnt to love them.
The yeasty bitterness of beer also took some getting used to, he says, but after applying the same approach - trying it with company - he has learnt to appreciate a good brew.
Right now, he is working his way through the stinkier cheeses. He has not reached the top of the mountain yet - Stiltons and the like are still too much - but the moderate blue cheeses are fine by him,
Following one's passion in a measured way might seem like an oxymoron, but it has been a signature of Mr Oeij's life.
The chartered accountant moved from the finance industry to the food and beverage business in his 30s and in stages, first taking up culinary courses, then becoming a chef-for-hire.
The Prive Group has just crossed into its 11th year of operation and there are now Prive outlets in Marina at Keppel Bay, Chijmes, the Asian Civilisations Museum, Clarke Quay and outside Wheelock Place in Orchard Road.
Besides these casual dining spots, there are the more specialist outlets. These are the seafood-oriented Bayswater Kitchen at Keppel Bay, the Chinese restaurant Empress at the Asian Civilisations Museum, the garden bar The Green Door at Dempsey, the American-style burger diner Roadhouse, also at Dempsey, and the nightclubs Bang Bang and Lulu's Lounge, both at the Pan Pacific Singapore.
And it is not just his palate that he is developing. He is proud of how his son Tyler, five, enjoys sashimi, wasabi and the taste of lemons. Mr Oeij's Instagram even has a clip of Tyler enjoying a stalk of raw kale.
Tyler is his frequent Instagram model. His wife Tracy Goh, who works in the group as marketing manager, makes an occasional appearance, as does Mr Oeij himself. He dubs her #greengoddess. His health-conscious wife loves vegetables, he says, and he posts her creations, such as a beetroot, millet and fennel "risotto" with bouquets of lettuce, on his Instagram account.
Eating with family and friends is an easy way to discover something or to overcome a dislike. I used to think beer was smelly. Living in London, drinking with colleagues, I'd go for vodka coke. But I started sipping beer and I've grown to love that yeasty, dry flavour.
MR YUAN OEIJ on overcoming food phobias and developing a more adventurous palate
The pictures, whether they are fun shots of family outings, a group portrait of employees or a sensual close-up of a head of roasted cauliflower topped with hazelnuts and Parmesan, are perfectly framed.
Photography is his other passion. When he was younger, Mr Oeij imagined he would take pictures for a living.
He had what he calls a "typical Singaporean education". From Catholic High School Primary to Raffles Institution to Hwa Chong Junior College, he went on to the London School of Economics, where he qualified as a chartered accountant. He stayed on in London after graduation, working as an accountant at Ernst & Young.
That path is just what one "latches onto, without thinking too much about the future", he says.
It was there, in the British capital's restaurants run by chefs such as Marco Pierre White and Gordon Ramsay, that his senses were opened to the possibilities of food.
"I remember the tartine with pears, which I later introduced in my own restaurants. I was eating risotto, finding out what that was all about and paying £35 for a dish, which I thought was breaking my bank," he says. "It was fascinating."
Like many boys, he never went into the kitchen as a child and dabbled in cooking at university out of necessity because he missed Singapore food. There was a lot of trial and error, he says.
"I made spaghetti bolognese with tomato ketchup," he says of his attempts in those pre-Internet days.
Work brought him back to Singapore in 2001. He was growing dissatisfied with work as a fund manager while his interest in the food business was growing.
"I didn't know many examples of people making a mid-career change and I didn't have the momentum or courage to take the plunge, so I went for the safe option," he says.
But the desire to be a chef would not go away, so he took courses at At-Sunrice, the local culinary academy and, in 2004, worked as a kitchen hand for a month at the Saint Pierre restaurant at its Central Mall location, where he prepared fish, meat and vegetables. It was over the Christmas season and hours were long and gruelling.
"When you stop moving, your body wants to shut down - I was not used to the heat and standing up for so long. But I was so psyched to be there and I enjoyed the experience," he says.
After that, he read up on the food industry, took up short courses on restaurant management and volunteered to assist in more kitchens.
Finally, in 2005, he quit his full-time job, with "vague plans", he says, to open a do-it-yourself salad place. But he decided Singapore was not ready.
While he looked for a restaurant, rather than just wait passively, he worked as a chef for hire.
He looked up friends, colleagues and business contacts, offering to cook at parties, or inviting them to his parties.
By charging up to $120 a head, people would vote with their wallets and he would get honest feedback, he says. He was fairly good at it, he says, working two or three parties a week.
That stage-by-stage approach allowed him to learn something about himself: He loved cooking, but found he liked running the entire business more and being in the kitchen did not give him the bird's eye view he craved.
In late 2006, he found a centrally located unit in River Valley Road with affordable rent and opened Brown Sugar, a bistro serving soups, steaks and salads. He hired a chef, but assisted during busy periods.
"Stressful and exhilarating" is how he describes his time as a first-time restaurant owner and in the two years it existed, it found a loyal base of diners who made the business profitable.
His late father, a businessman in the rubber import-export business, offered support and advice. Mr Oeij comes from a big family: He has seven older sisters and one younger brother.
Prive, at Marina at Keppel Bay, opened in 2007 and the others followed. At that time, he partnered with well-known restaurateur Michel Lu, but they have since parted ways.
Mr Oeij is now majority owner of The Prive Group and, for speciality operations such as its nightclubs, works with consultancy SJS Hospitality, founded by Mr Joshua Schwartz and Mrs Sarissa Rodriguez-Schwartz.
There were challenges along the way. Around 2011, times were bad and the group was bleeding money. Insolvency loomed, he says.
One major drain was Stereolab, then a two-year-old nightclub in the Pan Pacific. It was failing to draw the big spenders that would make a high-cost operation break even.
He made the call to close it and replace it with another nightclub concept Mink, with new partners. That was a hit and so was its successor, Bang Bang.
He and his wife married in 2011. They met at Spize eatery in River Valley Road, when they were seated at nearby tables and struck up a conversation. Over the years, she says, the man who moved from finance to restaurants has grown into his role, becoming more sure of himself.
"You can see it when he's dealing with difficult people, like suppliers and customers - he's more sure of what he wants," says Ms Goh, 37.
Most nights of the week, he comes home to dinner, she says. His speciality is seafood. His Teochew steamed fish is prepared perfectly - pink at the bone, she adds.
She takes care of salad duties and, in fact, leans towards vegan and vegetarian meals now, adding that it helps that son Tyler as well as his father have adventurous palates.
Family time revolves around food and that means checking out new restaurants as well as revisiting favourites, she says.
The Prive Group does not have any outlets outside Singapore, but Mr Oeij says overseas expansion will happen in time, just not right now.
This year, he wants to do something a little more mass-market: A chain of chicken rice restaurants. Instead of competing in the heartland and aiming at family diners - areas already staked out by hawkers and existing chains - his restaurants will cater to tourists and the younger generation.
"I don't want to sell ice to Eskimos. I will have tradition and heritage in the brand, but with a more contemporary feel," he says.
A serving for one will be under $10 and he is looking for outlets in the Central Business District and tourist-heavy spots.
He is working with Prive's chief executive officer Jean-Luc Vu Han, who he says has a more disciplined, structured approach to business, which complements his "dreamer" style.
The dream was never to be rich, says Mr Oeij, who draws a fixed salary. His family lives in a rented house in the Bukit Timah area, equipped with a "rusty and almost dying" grill and an "inherited wok" that lets him steam fish, he says.
"I've never extracted anything other than a salary. I don't lead a wealthy life and profits are reinvested into the company and into our growth."
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