How would traditional taste to someone who has spent their life on mass produced kikoman?

Kikkoman USA has been brewing a lighter soy sauce in Wisconsin for the U.S. market for a few decades while now. It’s what most people in the U.S. think of when they hear “Kikkoman”.

Specialty markets sell imported Kikkoman products, such as “traditionally brewed” soy sauce which tastes stronger. Note that “stronger” doesn’t mean “better”: Asian consumers are used to using different styles of soy sauce as they see fit. U.S. consumers still largely view soy sauce as a single thing with no variation except maybe “low sodium”. Definitely worth exploring the different varieties.

There's no one "traditional" soy sauce. It's kind of like wine. If you live your life only drinking sweet port wines straight from the bottle, you'll think a dry white wine is gross if you use it the same way. But if you're making a cream pasta or some sort of fish, you'll quickly realize white wine--and every wine--has its place.

For example, I find kikkoman to be absolutely awful for fried rice. It has an oddly sharp taste that just doesn't work. Chinese soy sauces don't have that sharpness but have a very wide and smooth savoriness that works well with fried rice. But if you try Chinese soy sauce with sashimi, it tastes flat and very wrong. That sharpness of a Japanese soy sauce works better, and a high quality Japanese soy sauce has a milder sharpness that emphasizes the fish flavors but not so weak that it makes the flavor weird like a Chinese soy sauce would.

I grew up on kikkoman, view it as the soy sauce equivalent of Heinz ketchup or Best Foods/Hellmans mayonnaise and still cook with it all the time. But after tasting a wide variety of soy sauce I would describe kikkoman's profile as salty, metallic and stout-beer like. The fancier soy sauces seem less salty (despite similar amounts of sodium) and can have varying notes of oyster sauce, seafood, sweetness, coffee, molasses and MSG.

Kikkoman has a double-fermented soy sauce in their product line, brewing starts with their regular soy sauce instead of salt water. The flavor is much deeper and more complex, it's actually less salty than regular soy sauce.

Another commentor suggests this is more like tamari than soy sauce. If it is, expect a similar but more intense flavor and an especially long after taste. It's hard to describe the more intense flavor. It's like if you only taste soy sauce with the center of your tongue, you taste tamari with the tip, center and sides.

Probably like tasting a whole different thing. Traditional soy sauce hits way differently, it’s not just salty, it’s got layers

Try Pearl River Bridge Light soy sauce. Is the default recommended light soy sauce for a lot of asian cooking, and easy to find.

You'll like it better than the harsh flavor of Kikkoman

Salty