I.S.U.: International Sour Units

I for one love the idea.

 

Would number 1 on the scale start with a sour? Would have thought not.

 

Sounds interesting and useful!

 

Can't we just measure ph? And wouldn't the type of sour kind of fudge with the numbers here? A beer with a lactic sour profile probably won't taste as abrasively sour as a beer with an acetic, vinegary profile, even if they may have the same ph, right?

 

I think that's the point; start with a sour that's not very sour as your lower baseline, and work upwards.

 

The difference is that IBU isn't some sort of subjective baseline dependent on taste, it's an actual measured calculation based on the alpha acids in various hops. How could you possibly objectively measure sourness?

 

You can measure acidity with the potential hydrogen value, but acidity isn't the only determining factor of perceived sourness.

 

Yeah I get that. Just saying since the basis was IBUs (which apply across a broad spectrum of beers), should ISUs not be consistent? Even if a lot of beers will score very low

 

number one would need to be like orval or something, not exactly 0 but pretty close to it from any "sourness"

 

Neither calculating nor measuring IBUs are very precise, though-
see Peter_Wolfe's post here for more detailed info:
http://www.beeradvocate.com/communi...et-this-sorted-out.191517/page-2#post-2558893

 

just like IBUs totally... meaningless.

 

It's called pH.

 

I'm not a huge fan of IBUs. Like you said, it's not precise, nor is it a good indicator of perceived bitterness. My only point is that it was something you can actually objectively measure and that I'm not sure how that would be possible with sourness. Acidity is not an accurate measurement of sourness in many cases either.

 

Neither are alpha acids the only determining factor of perceived bitterness.

 

Sounds like the next great "craft" marketing gimmick. (Not a moment too soon, either, as the "now in cans" thing has nearly run its course.)

 

I think the first sour on the scale would have to be the New Belgium Snapshot. Supposed to be a sour but not really, easily the starting base unit.

 

Perceived bitterness and perceived sourness in beer could, in principle, be made objective and measurable, but the people who have the requisite knowledge and skills have neither the money nor the motivation it would take to do it properly.

 

The log measure of the concentration of free hydrogen does correlate with sour taste, but it isn't the only contributing factor

Why not make 1 (or 0) water? Maybe thats just me

 

Yep, I second this notion. Jester King includes the pH of their beers along with IBUs, ABV, SRM, and final gravity. Personally, I think this is the most objective way to broadcast roughly how sour a beer might be. (I say it in this way because, like IBUs, measuring the pH uses objective data that serve as a useful reference point, even if the perceived sourness/bitterness is harder if not impossible to quantify; showing the pH would give the drinker a rough idea of what they might expect, though.)