Wednesday, May 12, 2004

Beer - it's what's for breakfast

I may just have to make this my default page - where else can you find the following information:
I can't figure out how people determine what a beer's IBU is. Is there some guy that just drinks a lot of beer? Is it a robot? I want one.

Nathan
MIT

As we noted above, IBU stands for International Bitterness Unit, which, in beer-nerd terms, is one milligram of iso-alpha acid per liter of beer, which also equals one part per million (ppm). Alpha acids are the compounds in hops that lend bitterness to beer, and when a brewer purchases hops, there's a value associated with the volume purchased that denotes the percentage of the weight of the hops that are alpha acids. And here's one of the easier formulas for calculating IBUs:

IBU =

Hops x AA% x U%
---------------------------
Volume x 1.34

Where:

Hops = weight of hops in ounces

AA% = alpha acid percent

U% = percentage of alpha acid that is actually used during the boiling process (this can be impacted by a slew of factors)

Volume = volume of the wort in gallons

1.34 = constant that converts milligrams into US standards

This is a great formula as long as you use fresh hops, because the power of alpha acids will diminish as the hops get older, eventually oxidizing or turning rancid, giving the beer a cheesy aroma and flavor. All in all, IBU is simply a rough estimate of how much bitterness is added to the beer.

MIT, eh? Check eBay for IBU robots. Look in “Home > All Categories > Lazy Bastards.”

Respect beer.
I couldn't have said it better...

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