Hop Terminology
Aroma
Much is spoken of the quality and intensity of dried hop aroma. These are strong varietal characteristics. There appears to be a general relationship between the type and heaviness of a hop aroma and the flavour and aromatic properties of beer.
Alpha Acid
A major component of the soft resins. When isomerized, these materials provide the main bitter compounds associated with beer. The alpha acid content varies widely among hop varieties from levels of 3 – 4% w/w in aromatic-type hops to levels of 13 – 16% in the bitter hops.
Beta Acids
A soft resin component, beta-acids are not bitter in the natural or isomerized form. Some of the oxidation products do provide bitterness, and the beta-acids can be chemically transformed into light-stable bittering forms.
Co-Humulone
The alpha acids exist in three analogous forms, humulone, ad-humulone and co-humulone; and the proportions of these analogues vary markedly with variety. Varieties with relatively low co-humulone levels are strongly favoured.
Storagability
Where available, analytical figures on varietal sheets show the % of Alpha Acid remaining after 6 months storage at 68f. Oxidation of alpha acids removes their ability to be isomerized to the required bitter isomers. In comparable circumstances, some varieties lose a greater proportion of their alpha acids to oxidation than others do. Cold storage and anaerobic conditions can delay oxidation. Some oxidation of essential oil components is necessary to produce compounds thought to be important in beer flavours, so controlled ageing is important for hops required for both bittering and aromatic properties.
Total Oil
This characteristic varies widely with seasons, varieties and growths from 0.5 mls to about 3 mls per 100g of hops. While the soft resin compounds are responsible for providing the bitterness to a beer, the quantity and composition of the essential oils are responsible for the amount of hop flavour and aroma in the beer.
Myrcene, Humulene, Caryophyllene & Farnesene
The four major components of the essential oils and between them they account for about 60 – 80% of the essential oils for most varieties. The compounds are all highly volatile hydrocarbons and during boiling of the wort most, if not all of them, are driven off and contribute only a little to hop flavour and aroma in beer. Therefore it is usually necessary to add late hops for additional aroma.
Whole Hop (Raw cones of the plant Humulus Lupulus)
With our unique combination of vacuum Packed “Freshpaks” in 5kg and 20kg packs and our comprehensive stock of over 100 different varieties from growers worldwide, all year round we can offer the brewer an artist’s pallet of flavours to create every type and style of beer.
Type 90 Hop Pellets (Hops milled/ground into powder then pelletised)
The most popular varieties are also stocked as Type 90 pellets. Sealed in vacuum packs, these are used in the boil for bittering or late on for aroma. They must be used in conjunction with a whirlpool or enhanced filtering system.
