Convenience of hop extracts

It is probable that the first attempts to process hops were motivated by a desire to arrest the decline in brewing value that takes place during storage [6]. Hops can lose up to 30% of their alpha acid content in a year and over 50% in two years. Apart from pressing, with the intention of excluding air, rightly believed to be instrumental in the deterioration of hops, these first steps were based on the methods of pharmacy, using aqueous and alcoholic percolations [7]. 

Compared with whole hops or pelleted hops, extracts offer a dramatic reduction in volume and weight and have therefore found favour where 

In order to arrest the decline in brewing value that takes place during storage, it is usual to keep hops in cold storage, which adds to the cost of an already expensive raw material. The need for this is avoided by extraction and sealing the extract into cans. Ambient storage is satisfactory and the space needed is much reduced. Cans of hop extract have been opened after ten years and found to have retained their full bittering potential. 

Like any natural product, hops are variable in quality and even hops of the same variety will differ in brewing value from farm to farm and from one year to another. Extraction offers an opportunity to smooth out these variations and to present a product with standardised brewing value. Apart from standardised bitter content, an extract may contain a specified blend of hop varieties or a standard volatile oil content which assists in the achievement of consistent hop flavour and aroma. 

Modern breweries rely heavily on automated procedures. While the addition of hops in their natural state does not lend itself to automation, extracts may be dosed by suitable metering pumps. This, coupled with the standardisation mentioned above, allows fully automatic addition to wort. 

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