Friday, September 16, 2011

Theoretical IBU's

Last night I managed to get my hands on a bottle of Mikkeller 1000 IBU IPA. It became famous upon its release in early 2010 as the most bitter beer ever made, supposedly it sports 1000 International Bittering Units, hence the name. Its unmistakably a very hoppy beer, initially leading in with some citrus and pineapple aromas and a subtle caramel malt flavour, this was followed by an almost oily texture punctured with bittering hops resulting in a long bittersweet finish that just kept expanding.

Whilst enjoying this beer, it got me thinking as the relativeness of IBU measurements in high alpha beers.

Hops play several roles in the production of beer, but in particular they are critical as a source of aroma, flavour and bitterness. More specifically the role of alpha acids associated with hop derived bitterness. These alpha acids, as they occur naturally, exhibit very poor solubility in water, which is why they must be boiled. This alpha acid component of the hop generally account for between 2% - 16% dry weight, with higher alpha hops being bred all the time. Thus, the greater the alpha acid content, the greater the amount of bitterness will add to the beer.

It is generally accepted that hop solubility in a given wort stops at around 100 – 120 IBU. As far as what we can taste, that is limited to 90 – 100 IBU. Therefore, theoretical IBU numbers are purely limited to how many hops a brewer can fit in their kettle.

A beer at 50 IBU’s with no malt depth to balance the hop bitterness might as well be poured down the sink as the acrid hop element will render the beer far to bitter. Alternatively, a 100 IBU IPA with a plethora of malt depth to the beer simply balances it out and adds a tremendous complexity, or balance.

In this current brewing world where one upmanship regularly raises its ugly head, IBU measurements are almost discountable. The responsibility of the brewer is to present the beer (including hop character) in its best possible form taking into account a variety of attributes, but most importantly drinkability and balance.

It must be balanced – period.

That’s why this Mikkeller 1000 IBU IPA succeeds, even if the name is slightly misleading.

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