I know which restaurants in my town have “good Cokes” (which also includes Pepsi.) Monical’s Pizza, McDonald’s, McHugh’s, all have drinks with the right proportion of syrup and carbonated water. Other restaurants, like Subway, have Cokes that taste like brown water. I know when there is too much syrup, and I know how a Coke tastes when the syrup has run out, but this is neither of these. It is a flat brown liquid that tastes like dreck, and it is like that every day. I just stopped at a McDonald’s that is midway between my house and a family member’s house, and the last 4 or 5 times I have been given a tasteless drink, which is unfortunate because it’s a good half-way point on the trip and there is nothing for 20 miles in either direction. Anyway, I can only guess this is a way for the owner/manager to save money. How much would watering Cokes in a small town save? Does McDonald’s or Subway have any say in how people operating under their names serve drinks? Am I the only one who has such a sensitive soft drink palate?
I know exactly what you mean. At one MacDonald’s in a neighbouring town, the Coke consistently tastes . . . not only flat, but almost like it’s gone bad. I don’t know anything about whether or not there are corporate rules for mixing syrup with seltzer, but when I’ve complained, the workers merely shrug as though it’s MY taste that’s off rather than that of the Coke. That has me wondering the same as you: Am I the only one who’s noticed?
The McDonald’s machines arrive at the stores with factory-set ratios. There may be a way to tamper with the setting, but it is not apparent.
I notice the quality of fountain drinks too. There’s a little Chinese take out place I go to that’s perfect.
Send a note to McD’s HQ—something is off in the Brix, or the heads need to be disinfected. The note should set off a small firestorm–they do pay attention to those things.
Since you say it’s flat, that sounds like a CO2 issue rather than a syrup issue. But that’s just a hypothesis.
Coke comes in and tests the machine to see if the right mix is being distributed on a regular basis. Failing that, things that can screw with the taste are the syrup being out or ice not being in the machine.
Once you’ve had the ineffable joy of cleaning the mould out of a soda fountain, you will probably not order fountain drinks again.
My friend’s husband worked for Pepsi years ago and he says the same thing.
My standing restaurant order of a glass of water sounds better and better all the time. 
Most glasses of water in restaurants come from soda fountains.
There is typically a white lever next to one of the flavors that dispenses only water.
I thought they came from the tap.
That’s what gives it its flavor!
I’ve found McDonald’s to be the only place that serves Coke in the right proportion of syrup to carbonated water. I’ve never had a bad Coke from McD’s. I will not get fountain drinks anywhere else. I think McD’s also has a high sanitary standard with it’s machines. You may get a store here and there that are bad, but overall, I can count on their Coke to be quality. I think lots of other places don’t clean their machines often enough.
McD’s Coke always seems to be as greasy as the food to me. Might be just perception.
I became a diehard loyal customer to QuikTrip because their fountain sodas are perfect. The first time I had one it was like angels singing. Soda is srs bsns.
And they have the good pellet-ice. I loves me some QT.
When I worked as a assistant manager and as an inspector for a nationwide chain of fast-food restaurants (late 80s, early 90s), we were the only ones that ever checked the ratio of syrup to carbonated water. Coke never came in and checked nor would they have been allowed into the back of the restaurant. This just wasn’t something that ever happened.
I worked at a series of movie theaters years ago, and the manager had a tool to check the Coke syrup ratio. IIRC, it was a double test-tube type of device that was proportioned correctly for the syrup & water. He’d just fill the tubes & if the levels two different-sized tubes was even, that was the “official” ratio. He’d usually bump the syrup just a bit for flavor, but couldn’t bump it too far because he had to get a certain yield from it. We always had the best Coke.
There used to be a ship down in Long Beach/San Pedro, CA called the “Princess Louise” that was turned into a restaurant. I think there was something odd in their ice because their sodas always had an ammonia-like flavor. ick.