A question regarding the Japanese iced coffee method

I read, and tried the recipe referenced in, Peter Giuliano’s “Why you should stop cold-brewing, and use the Japanese Iced Coffee Method”. The method has been championed by people I respect, notably, in my memory, by Nick Cho of Wrecking Ball Coffee.

Q: Using this method, aren’t we messing with the ratio of brewing water to coffee?

It seems like this technique throws out everything I’ve learned about the importance of the water to coffee ratio during brewing, and simply reduces one variable without accounting for any adjustments needed in the others. Half the brew water never makes contact with the grinds. Doesn’t that mean we are under-extracting?

I tried the recipe on my v60, using a coffee I had previously only brewed hot…

What I got was certainly palatable — crisp, not bitter — but I could taste the ice. It was a mild cup.

I’ll cop to some responsibility — I should get some baking soda in the freezer — but I suspect if I had a more proper level of extraction it would have been less of an issue, with the flavor of the coffee predominating. 

I’d be interested in your comments.