Does Coca Cola and Pepsi taste different from the 1970s to today and do they taste different from country to country?

Yes. There was a famous marketing scandal called New Coke. Additionally, Coke in different countries has different ingredients. "Mexican Coke" is sought after in the states because it has cane sugar rather than high fructose corn syrup.

New Coke was the 80s, not 70s — they actually briefly brought it back as part of a Stranger Things tie-in. Super interesting to actually taste it.

The World of Coca Cola museum in Atlanta, GA has a room that lets you try the various Coca Cola beverages from around the world. It’s an interesting experience.

It can taste different in the same city / from different sources.

The water sources will be different (mostly filtered city water) and bottled, caned, fountain drinks at restaurants can all vary slightly due to many factors. In some countries different types of sugar/sweeteners may be used, the US has highly subsidies corn so in the us HIGH FRUCTOSE CORN SYRUP is used, where you will see sugar listed in other countries.

Some restaurants will get the mix in bags, others in metal canisters this can impact taste on top of the equipment that mixes and carbonizes the mix.

This is only true for coke. Pepsi has centralized bottling. Coke does local bottling.
- Points of bottled, vs canned vs the mix at the fountain all apply. Just not the local part.

Pepsi, I can't say I can tell a difference over the years.

But Coke? Fuck yes. Coke used to have a much crisper taste back when I was a little kid. Then they did new coke in the 80s, and classic coke was different than what I had before that. Classic coke was absolutely not the same flavor.

So the original one was better I assume?
- Oh yeah, much better.
  
  You know how coke kinda coats your tongue and has that one note cola heavy flavor? Back then, the coating thing didn't happen unless you chugged it. The flavor had depth, kinda like how a good root beer has layers of taste. Don't get me wrong, it was still very cola dominated, but it was like the difference between instant coffee and a decent bean you grind yourself. Or like going from budweiser to a good craft ale, if you're a beer drinker. Or maybe like Dr Pepper vs Mr Pibb
  
  The original was a very yummy thing rather than a sugar bomb with a single flavor.
  
  I do sometimes wonder if maybe the lens of memory into youth exaggerates the change, but I've met other people that have distinct memories of the taste as well.
  
  I don't hate coke as it is today, but it used to be better for sure

In Australia Coca-Cola is made under licence by Coca-Cola Amatil (not the same company), and the full sugar version uses local cane sugar. I don't know if the recipes for the sugar free versions are different to the US, but I suspect they might be in order to better match the taste of the local full sugar recipe.

Coca Cola will vary in flavor between product made with high fructose corn syrup and natural sugar.

Coke in Argentina and the USA (and probably many other countries) taste more sweet than the Coke in Europe/Spain.

Here in Spain regular Coke doesn't taste that sweet so I end up getting the Zero Coke because it has no calories.

Same with Sprite and much more stuff. For example the Froot loops here they sell some version that has different colours and they are barely sweet compared to the US version.

I think they taste different with corn syrup versus sugar, and in plastic bottles versus glass bottles.

I can only say Coca Cola taste the same in The Netherlands, Germany, and Vietnam. While I can generally tell quite well when I get a different cola then a Coca Cola one. Based on that there should be some kind of international standard?

I can imagine US being different due to less strict rules around food than EU (much American junkfood is altered in the EU market due to this). But then I'm suprised Vietnam taste the same for that same reason 🤔.

I can give you some insight. Coca Cola sends different recipes to different factories depending on the water used to make Coke so that it always tastes the same wherever you buy it.

The biggest difference between cokes around the world comes from the sugars that are used to make Coke. Different quality of sugars produce different qualities of beverages. It all depends of the sugar supplier of the factory.
- I generally drink Zero. If the sugar is the different, could that be why?
  
  Zero taste the same as regular to me but less sweet, but since I rarely drink regular I don't have the exact taste of that in my mouth.
Same sort of experience. It tastes the same in the UK as it does in Spain.
- In my experience the one in Spain is less sweet than the one in the USA. Same in France.
  
  I recently travelled to France and the fridge was so cold it had frozen half of the coke. Then I tasted it and it felt like the USA version. But then I realized it was because most of the water was still frozen while the rest of the Coke was already getting unfrozen and felt more concentrated/sweet. For a day I thought the Coke in France was also sweeter.

I just want to say that India’s Thumbs Up cola (a Pepsi brand) is the tits. Cardamom belongs in cola. I would have never guessed.

That sounds freaking good. I would put a trace of cardamom in everything if I could.

They both taste like shit in Australia

Thanks for the replies everyone. May I ask one more thing, is it safe to assume, the coke that they serve in fast food chains like KFC and McD, they are diluted and having more sugar to save cost?

Yeah pretty much most bars and restaurants will use a mixer gun for providing soft drinks. It's usually carbonated water and it will inject syrup for coke, pepsi, sprite etc at regular intervals. The syrup is just a box from the drink company that they have hooked up to pipes out back

Not just countries, but depending on the size of a country it can taste different depending on the region of the country you're in. For example, whenever I go to another state, sodas of all varieties taste off. It isn't super different, but it is strange and it takes some getting used too.