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Hop Oil No. 1 - premium varietal blend

Hop Oil HAL - regular varietal blend

Varietal Hop Oils - oils from specific hop varieties

General description: Blended or generic hop oils are a mixture of whole hop oils separated from liquid CO2 extracts by vacuum distillation. They are suitable for use either on a pre- or post-fermentation basis to provide consistent late hop or dry hop character to beer. Hop Oil No. 1 is a consistent blend of English Wye Target and other varietal oils. Hop Oil HAL is a similar blend but with rather less flavor impact. It is, therefore, a rather less costly source of whole hop oil but provides a good foundation for the expression of other hop characteristics in beer. Varietal Hop Oils are whole unblended oils prepared from specific single hop varieties.

Hop Oils are obtained by purely physical fractionation methods with no chemical processing whatsoever.

Preparation: Hops are extracted using liquid CO2 at a temperature of 7-10° C and a pressure of 50-55 kg/cm². CO2 is removed and the extract recovered at a temperature of 14-15° C.

Under carefully controlled conditions, the essential oils are high-vacuum distilled from the whole extract. This combination of gentle processes present the essential oils in an undamaged condition and in a high yield. The oils are blended to match the traditional steam-distilled character and aroma qualities of the hop varieties used. Whole oils from a number of varietal sources are blended in a consistent fashion. This helps to remove the variation inherent in single varietal oils that may occur from batch to batch and year to year.

The varietal oils are prepared in the same fashion but remain unblended. They, therefore, retain the full aroma character of the specific hop variety.

Composition: Both blended hop oils are pure essential oils from a number of hop varieties. They and the varietal oils contain the full range of essential oil components including the major mono- and sesquiterpenes, oxygenated compounds and sulphur compounds. There are no soft resins or other hop components present.

Uses and advantages in brewing: Hop Oils may be added at various stages in the brewing process depending on the desired effect. Two examples of their use are as follows:

Pre-fermentation addition: If it is required to add Hop Oils at this time, it is best to add them to the whirlpool. In this manner, the aroma addition is consistent in both quality and amount; and, therefore, highly repeatable. When used in this way Hop Oils produce a true late hop character in a much more controllable fashion than is the case with leaf hops or pellets.

Post-fermentation addition: If it is required to use Hop Oil to impart a dry hop flavor to beer then the addition should be made to the conditioning tank during filling or rousing to assure good mixing. This duplicates the effect of dry-hopping cask conditioned ales without the problems associated with the use of leaf hops or pellets in this role.

If the beer is to be racked, addition of Hop Oil may be made to the racking vessel. In this case, rolling of the individual casks becomes unnecessary resulting in substantial labor savings.

Method of use: For pre-fermentation addition, the amount of Hop Oil to add is calculated to equate to a similar addition of leaf hops or pellets made at the same time. For post fermentation addition the rate is based on the desired concentration of Hop Oil in the quantity of beer to be treated.

In both cases the desired quantity of Hop Oil is mixed with Hop Oil Base (see Hop Oil Base - Product Information Leaflet) in the approximate ratio of one part Hop Oil to five parts Hop Oil Base. The mixture should be shaken vigorously until a uniform dispersion is obtained. This mixture should then be added to a small quantity of beer and reshaken. This produces a water-dispersible mixture that should be added immediately to the receiving vessel.

With a pre-fermentation addition the continued boiling and subsequent movement of the beer will ensure thorough mixing. Addition to the conditioning tank or racking vessel must be made during filling or rousing to ensure good dispersion.

Typical brewing performance: On a pre-fermentation basis Hop Oil provides at least the same intensity of hop aroma as an equivalent oil addition in pellets or leaf hops.

On a post-fermentation basis the rate of usage for light to medium beers is between 1 and 2 ppm. With heavier beers additions up to twice this amount may be necessary.

Options: Apart from the premium Hop Oil No. 1 and the regular Hop Oil HAL, certain varietal oils are available as stocked products. These include East Kent Golding, Hersbrucker, Styrian Golding, Wye Challenger and Wye Northdown. It is possible to produce sample quantities of oil of any hop variety normally available in CO2 extract form. Varietal oils are necessarily more costly than the blended oils.

Availability: Hop Oil No. 1 and Hop Oil HAL are both immediately available in stock in small or large quantities. So too are the varietal oils referred to above. Additionally, varietal oils can be prepared in sample quantities from most minor hop varieties.

Methods of evaluation: Pilot trials and evaluations are recommended to gain experience with Hop Oil in brewing plants of any size. Add the oil at a rate suggested in the "Method of Use" section in the manner described. Taste tests will suggest further rate adjustments.

Procedures for evaluating Hop Oil on small quantities of beer: The following procedures are suitable for an initial evaluation of Hop Oil on a small scale or laboratory basis. To follow these procedures you will need a 1 ml syringe graduated in 0.1 ml increments plus some Hop Oil and Hop Oil Base.

Barrel basis: (31 gallon U.S. Barrel) Take 0.2 ml Hop Oil and add to 1.0 ml of Hop Oil Base. Shake vigorously until a dispersion is obtained. Add the whole of the freshly prepared suspension to 50 ml beer and mix well. Add 30 ml of the beer suspension to a barrel of beer and leave to stabilize. This procedure results in a 1 ppm concentration of Hop Oil in beer. Compare the taste of the treated beer with untreated. Repeat the addition of freshly prepared suspension until the desired taste is achieved.

Five gallon brew basis: Take 1 ml Hop Oil, add to 5 ml of Hop Oil Base and shake vigorously. Add the freshly prepared suspension to 46.8 ml of beer and re-mix. Take 1 ml of the beer suspension and add to the 5 gallon brew. Mix and leave to stabilize. This results in a 1 ppm concentration of Hop Oil. Taste the beer and repeat the addition until the desired taste is achieved.

Bottle basis: (355 ml U.S. Bottle) Take 0.1 ml Hop Oil and add to 0.5 ml of Hop Oil Base. Shake vigorously until a dispersion is obtained. Add the freshly prepared suspension to 140 ml of beer and mix well. Chill a 355 ml bottle of beer to normal drinking temperature. Remove the crown cap. Add 0.5 ml of beer/oil suspension to the bottle beneath the surface of the beer. Tap the side of the bottle to induce fobbing and hence expulsion of the air. Reclose the bottle with a manual crown cap, invert several times to ensure mixing and re-chill for at least two (2) hours before opening and tasting. Each 0.5 ml of the prepared beer/oil suspension added to a 355 ml bottle results in the addition of 1 ppm Hop Oil to the beer. Prepare several bottles at concentrations up to 5 ppm Hop Oil for testing and select the level with the desired taste.

All these procedures allow simple incremental additions allowing resolution of addition rates to a fraction of a ppm concentration of Hop Oil.

Technical assistance with the use of Hop Oils is available on request.

Physical properties: Colorless to pale yellow mobile liquid. Certain varietal oils may have an olive green tinge.

Chemical properties: Immiscible with water. Disperses in 96% ethyl alcohol to give a hazy solution that eventually separates. Soluble in hydrocarbon and chlorinated hydrocarbon solvents.

Packaging: Available in brown 25 g (28 ml) amber Boston round bottles with teflon caps. Also available in 1 kg (1120 ml) quantities in aluminum bottles.

Storage: Hop Oil No. 1, Hop Oil HAL and the Varietal Oils should be stored in full sealed containers in a cool place. With glass bottles prolonged exposure to sunlight should be avoided. Hop Oils should not be transferred to mild steel or plastic containers.