Every article about slow fermented dough is written for people making it. Almost none are written for the people eating it, which is the far bigger group.
Search for cold fermented pizza dough and you get about forty recipes. Ooni, Serious Eats, Baking Steel, a dozen blogs with a 4.7 star rating and a thirty one hour prep time. Every one of them is written for somebody standing in their own kitchen with a bag of flour and a free weekend.
Nobody writes the other version. The one for the person who is not making pizza, only eating it, and who has noticed that some pizzas sit perfectly fine and some pizzas quietly ruin the rest of the evening.
That is a strange gap. The second group is enormous and the first group is a hobby.
What is actually happening in those three days
Fermentation is yeast and bacteria eating sugar. Everyone knows that much. The part that matters if you are eating out is what else they eat while they are in there.
Wheat contains fructans, which are chains of fructose molecules that human digestion handles badly. Fructans are one of the FODMAPs, the group of carbohydrates behind a lot of what people describe as a sensitive stomach. They pass through the small intestine more or less intact, arrive in the colon, and get fermented there instead by your own gut bacteria. The result is gas.
Yeast eats fructans too, given long enough. A dough that rises for two hours has barely started on them. Work on slow fermented bread has found that extending fermentation reduces fructan content substantially, with most of the reduction happening well after the first couple of hours rather than during them.
So the thing that makes a slow dough taste better and the thing that makes it easier on certain stomachs turn out to be the same process. Nobody designed it that way. It is just what happens when you leave dough alone for long enough.
The bit where I have to be careful
None of this makes pizza gluten free and none of it helps with coeliac disease. Coeliac is an autoimmune response to a protein, and fermentation does not remove the protein. If you have a diagnosis, a 72 hour base is exactly as off limits as a 90 minute one, and anybody telling you otherwise is selling something.
What I am describing applies to the much larger group who have never been diagnosed with anything, who say pizza does not agree with them, and who have quietly filed themselves under slightly gluten intolerant. Some of those people are reacting to fructans rather than gluten. Some are not. The research is real but it is not settled, and I am suspicious of any restaurant that starts making health claims about the dinner.
I will say this much. I know several people who avoided pizza for years and eat it happily now, and the variable that changed was where they were eating it rather than what.
Why hardly anyone bothers
Here is the commercial reason, which explains the whole thing better than any argument about flavour.
A 72 hour dough means every ball you serve on Saturday was mixed on Wednesday. It occupies refrigeration for three days. Fridge space in a small restaurant kitchen is the scarcest thing there is, and you have just filled a good part of it with stock you cannot sell yet.
Worse, you are forecasting. On Wednesday you have to guess Saturday. Guess low and you turn people away on your best night of the week. Guess high and you bin the difference, which is flour, labour, and three days of running a fridge.
A same day dough deletes the entire problem. Mix at ten, serve at six, make more if it goes well. That is why the chains work that way. It is not laziness, it is cash flow, and any accountant would tell you they are right.
Which means that when you find somewhere doing the slow version, you have found a kitchen making a decision that costs them money for a reason that only ever shows up on the plate.
How to tell without asking
Look at the rim. A long fermented base has an uneven cornicione with large irregular holes, some of them the size of a fingernail, and dark blistering across the surface where the bubbles caught the heat. Pizza people call that blistering leoparding.
A fast dough gives you a rim that is even the whole way round, tight inside, and roughly one colour. It is not bad. It is a different thing, and once you have seen the difference side by side you cannot unsee it.
Then taste for a faint sourness underneath the tomato. Not sourdough bread sour. Just enough background acidity to stop the whole thing tasting flat.
Where to actually eat it in Ireland
There is more of it about than there was five years ago, mostly in Dublin and Cork, and increasingly in places you would not think to look.
The one that surprised me most was in Cavan. Luso does sourdough pizza in their restaurant in Cavan on a 72 hour proof, using regeneratively farmed flour and water from a local well, baked in a stone oven. It is as good as anything I have eaten in Dublin. It also sits behind a pub on Church Street with no shopfront, which tells you roughly where the energy has gone, and it is not into signage.
I am aware how that reads. I would not have mentioned it if the base were not doing the specific things described above.
The thing worth taking away
Fermentation time is the cheapest quality signal in food and almost nobody prints it on a menu. Sourcing gets a paragraph. The oven gets a paragraph, usually with the word stone in it. The dough, which is most of what you are actually eating, gets nothing at all.
So ask. It is a fair question and the answer takes two seconds. If it comes back as a number of days rather than a shrug, you are probably in the right place.