‘Timid” flavours. A bad car park. A mild curry that was an insult “to both India and lamb”. A suffocating profusion of carrots. “Monogrammed tat”. “Chalet-girl food”, ranging from “the basic and acceptable to the not very good at all”.

In his review last weekend of the restaurant at Ballymaloe House, the Sunday Times food critic AA Gill ran through the gamut of acidic put-downs. "Altogether, you could sense that this is a kitchen running downhill," he wrote. "A dining room that had possibly once been epic and was now just adequate . . . sad and expensive."

So far, so searing – and hardly the 50th-birthday present the Ballymaloe staff hoped for when they seated Gill, his partner, Nicola Formby, and their twins for dinner four weeks ago.

Yet how much does a bad review, even by a big beast of the critics, actually matter to restaurants?

Too many critics spoil the broth

“It’s hard not to be hurt by a negative review,” says Ed Cooney of the Merrion Hotel, in Dublin. In his 20 years the award-winning chef has seen the good, bad and the ugly of critics.

“By their nature they [Ballymaloe] will have put a lot of themselves into the food, into creating the menus, and the whole execution. You still have to stand back and see if there’s merit in the review. Can it be done better? You need to be honest with yourself. A bad review can be helpful. But today, with social media, everybody’s a critic.”

Derry Clarke, head chef with the Michelin-starred Dublin restaurant L’Ecrivain, says a bad review can often be good for a restaurant. “I built my place up on complaints. I think about a complaint more than a compliment. A complaint done the right way is brilliant; it makes you better.

“We’ve had a few reviews over the years where the waiter or the chef was picked on – they’re the worst ones. But you get a much bigger reaction, much more publicity, from a bad review. I always respect serious reviews, good or bad, from a professional working for a newspaper. Give me a professional reviewer any time over some gobs***e on TripAdvisor.”

Padraic Hanley, owner of Ouzo’s Bar & Grill in south Dublin, knows all about outrageous internet comments. After some “ridiculous” criticism in September on TripAdvisor, Hanley posted a thorough rebuttal, only to see it deleted by the website.

“We’ve had our share of reviews, good and bad, by professional critics,” Hanley says. “But somebody needs to tackle the online stuff, as there’s no verification.

“A negative review by a big critic can be very hard on the staff. A lot of the time you have to build the staff back up and say, ‘Listen, get on with it.’ You’d analyse it, though. You go through the whole thing. AA Gill is probably the biggest there is. But would it stop me going to Ballymaloe? I don’t think so. It’s a well-respected restaurant.”

And what of Ballymaloe itself? The east Cork cookery school, event centre, farm, wine shop and restaurant is regarded by many as the spiritual home of Irish cooking. Understandably, they’re eager to downplay any fallout.

"We're disappointed to get the review, but you can't be all things to everyone," says its manager, Hazel Allen. "AA Gill didn't get what he expected. Maybe he expected something more . . . opulent. That's unfortunate, but we don't feel he's jeopardising our business. We're in the game a long time. It could be a positive."

Allen has run the hotel and restaurant since its Michelin star-laden, late-1970s heyday, and the accusation that the kitchen was “running downhill” smarted.

“I think that remark is harsh, because he’d never been here before. It was a little bit hard to understand. Having read the article, there’s been a good bit of chat in-house about it. It’s important for us not to have our confidence shattered, and we’ve been careful about that.”

While the Allen family take stock in Shanagarry, the scene at the English Market, in Cork city, is one of quiet jubilation. There, staff at the Farmgate Cafe are basking in the glow of their five-star review by the same critic.

“We were delighted with it,” says its manager, Rebecca Harte. “It was very exciting for everyone in the market. I’m sure there will be a bounce. Reviews do matter. You’re in here day in, day out, and you work hard for whoever walks through the door. On this occasion AA Gill came in and queued up, and it was obviously great for us.

“A bad review can be very disheartening. Maybe sometimes it’s a wake-up call, but I’d be more concerned with a customer who’s been coming day in, day out, telling me they’re unhappy. You’re not performing for tourists.”

Harte remembers being on the receiving end of a bad review in July 2012. The critic Tom Doorley took a dislike to their coffee. When they changed their blend around the same time, Harte had a near-revolt on her hands. “One customer came up; she was almost teary-eyed,” she says, “saying she’d loved our coffee for 20 years, and told us to change it back. And we did. We were very upset that Ballymaloe were dismissed like that, because they’re superb at what they do. Everyone has an off day.”

Not least, it appears, food critics themselves. Along with denigrating one Cork restaurant and lionising another, Gill also found time in his Sunday Times review to misname a Seamus Heaney poem, invent a new Cork delicacy ("dasheen") and pay a tribute to that unsung hero of 1916 James Pearse. Top of the morning, Adrian.