International Bitterness Unit

Label on the back of the Karlsberg Brewery with information about the bitter units

The International Bitterness Units ( IBU ), originally EBU ( European Bitterness Unit ), is a unit of measurement ( bitter unit) defined by the European Brewery Convention (EBC ) for the alpha acid content in beer , which should not be confused with the real bitterness of beer should be. This is determined spectrophotometrically in an isooctane extract from the beer. A specific determination of the bitter substances contained in beer is made possible by high-performance liquid chromatography (HPLC).

description

IBU is a unit of weight of one part per million ( ppm ) isohumulone (alpha acid) from the added hops. The IBU is determined using the following formula:

${\displaystyle IBU={\frac {10}{3}}\cdot H\cdot \left(A+{\frac {B}{9}}\right)}$ With

• H is the concentration in grams per liter of hops;
• A is the concentration of α-acids in the hops, in percent;
• B is the concentration of β-acids in the hops, in percent.

The scale and the methods for determining the initial EBU set by the European Brewery Convention, where the numerical values should be the same as in the "International Bitterness Units scale" (IMU), which in cooperation with the American Society of Brewing Chemists set has been. Since the process of determining the EBU and IBU values ​​varies slightly, the EBU can theoretically be somewhat smaller than the IBU.

When the IBU technique was introduced, another method was introduced which was based on measuring the concentration (in milligrams per liter; PPM) of IAA isomerized alpha acids (e.g. humulone ) in a beer, causing confusion led among the small brewers. The American Society of Brewing Chemists described the difference in the two methods of measuring bitterness as follows:

"While the results of the IAA methods are practically identical to those obtained by the [I] BU method for beer brewed with fresh hops, the IAAs of beer brewed with old or poorly stored hops, and with certain special hop extracts, can be significantly lower than the [I] BU figure. "

Typical values

In principle, the higher the IBU value, the more bitter the beer. However, the subjective impression of bitterness decreases with increasing malt content, so that heavier beers require a higher IBU value for the same bitterness. American light lagers are worth around 5 IBU, and most commercial beers are worth around 16 IBU. For beers with more complex flavors, the value increases rapidly, often around 60 to 70 IBU. IBU values ​​above 100, as for an exceptional India Pale Ale , are rarely achieved.

• hop-free herbal beers : 0
• Ale , dark: 15–25, in USA also higher: 25–45
• Ale, light: 15–30
• Altbier , Düsseldorfer Art: around 25; rarely up to 55
• Barley Wine : 35–70, in USA also over 90
• Belgian beer : 11-23
• Berliner Weisse : 0-8
• English bitter: 20-35
• India Pale Ale : 40 and above
• Irish stout : 30-70
• Kölsch : 18-25
• Märzen / Oktoberfest: 18-25
• Pilsner : 30-45
• Porter : 20-40
• Black beer : 20–30
• Wheat Doppelbock : 10–30

Web links

• Recipe Formulation Calculations for Brewers 1994  ( page no longer available , search in web archives )
• IBU chart by beer type

Individual evidence

1. ^ Lehigh Valley Homebrewers: Beer and Brewing Glossary . 2007. Archived from the original on September 24, 2008. Info: The archive link was automatically inserted and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved on August 5, 2009: "IBUs (International Bittering Units) - The accepted worldwide standard for measuring bitterness in beer, also known as EBU, based on the estimated alpha acid percentage of the hops used and the length of time they are boiled. " 
2. ↑ ^{a b} Methods of Analysis . In: American Society of Brewing Chemists (ed.)  . 1996, S. Beer-23: 1-4.
3. ↑ Norm Pyle's Hops FAQ Compiled / edited by Norm Pyle, 5/4/95
4. ^ European Brewery Convention: The Analysis Committee . Archived from the original on May 19, 2009. Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved August 5, 2009: “The EBC Analysis Committee also works closely together with the American Society of Brewing Chemists (ASBC) to establish so-called International methods with world-wide recognition of applicability. A partnership declaration between EBC and ASBC has been signed. The integration of the IOB methods of analysis and EBC methods is nearing completion. " 
5. ↑ ajdelange: Difference between IBU and EBU . June 11, 2009. Retrieved on August 5, 2009: "Because the absorption decreases pretty quickly with time at the completion of extraction the EBC reported value will, in general, be a little smaller than ASBC reported value unless the beer requires centrifugation. For all practical considerations the two systems should give the same results. "
6. ↑ What Is an IBU… Really? In: Basic Brewing Radio of March 20, 2008
7. ^ ^{A b} Andy Crouch: The Good Beer Guide to New England . books.google.co.uk, May 31, 2006, ISBN 9781584654698 (Retrieved July 10, 2010).
8. ↑ 1995 AHA Style Guidelines ( Memento of the original from September 30, 2009 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.