TETRAHYDRO-

ISO-ALPHA ACID

EMULSION

 

Purpose:

Tetrahydro isomerised hop extract is added post-fermentation to provide beer with hop bitter flavour, light stability, and enhanced foam stability. Because tetrahydro-iso-alpha acids have a greater impact on sensory bitterness than normal isomerised alpha acids, less tetrahydro isomerised hop extract is needed to achieve the desired level of bitterness. Emulsified "Tetra" is a physically stable product and is produced from CO2 Pure Resin Extract.

Description:

This product is usually a 10% or 20% dispersion of emulsified tetrahydro-iso-alpha acids in water. It is produced by hydrogenation of iso-alpha acids and is formulated in water using food grade emulsifiers.

Readily pourable, opaque, buff coloured liquid. Density of approximately 1.00.

Product Use:

The best utilisation of tetrahydro iso-alpha acids is obtained by distributing the emulsion, uniformly, throughout a large volume of beer, avoiding local high concentrations. This product must never be used post-filtration.

 It is necessary to dilute the emulsion with pH adjusted (10.0-11.0) de-ionised water to approximately 1% concentration prior to dosing.

 Tetrahydro isomerised hop extract can be injected into the flowing beer stream at a convenient point between the end of fermentation and final filtration, preferably where minimal yeast is present. We recommend injection over at least 70% of the beer volume.

Storage:

We recommend that tetra emulsion is stored at temperatures <25oC (prolonged storage at warmer temperatures should be avoided as some breakdown of the emulsion may occur). The product is physically stable, however, any slight layering of the emulsion, which may occur after longer periods of storage, is overcome by simply shaking the container, briefly, prior to use. Prolonged storage at temperatures >25oC may result in some breakdown of the emulsion and should be avoided.

Dosage:

Each brewery will need to determine its required dosage rate(s). THIAA's are about 1.6 - 1.8 times more bitter by taste than normal iso-alpha-acids (IAA's). The dosage rate for tetrahydro isomerised hop extract compared to normal kettle bittering depends on two factors:

a.

The difference in utilisation

b.

The difference in sensory bitterness.

 

For foam enhancement alone we recommend addition in the range 2 ppm - 5 ppm THIAA, added post-fermentation (pre-filtration). This is equivalent to approximately 3.6 ppm - 9.0 ppm sensory bitterness in beer. The utilisation should be in the region of 70%. The remaining bitterness may be derived from any conventional hopping method.

 If the objective in using tetrahydro isomerised hop extract is to provide protection against light-struck flavour, 100% of bitterness must be derived from reduced isomerised hop extracts.

 For avoidance of light-struck flavour stringent precautions must be taken to avoid even traces of regular hop bittering substances in the wort, yeast and beer. This includes isolation of wort, post pitched beer and a separate yeast handling system.

 Yeast used in a brew which has been hopped in the kettle using conventional hopping materials will carry over sufficient adsorbed hop bitter substances to invalidate the protection provided by the reduced isomerised products.

 Wigan Products would be pleased to discuss with you the complex properties of isomerised products and advise on specific applications.

Analysis:

Spectrophotometric (E1%=254nm) and high performance liquid chromatographic methods for the measurement of THIAA in extract and beer are available on request. Please note that for HPLC analysis, the emulsifiers are not soluble in methanol, therefore, methanolic solutions require filtration prior to injection onto a HPLC column. For the determination of beer bitterness modifications of "E.B.C. 9.6 International Bitterness Assessment in Beer" are required if this is to be correctly assessed

Packaging:

The Material is offered in 25 litre polyethylene containers with a nett weight of 25 kilograms. Other containers can be supplied if required.

 

 

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Ó Wigan Products Ltd. 1997