TETRAHOP GOLD®
Tetrahop® Gold is an aqueous alkaline solution of the potassium salts of tetrahydro-iso-α-acids. It is produced from CO2 hops extract using a patented all aqueous process. Tetrahop® Gold enhances beer foam when used as a postfermentation replacement for a part of the normal bittering. In the absence of normal α-acids and iso-α-acids, Tetrahop®Gold will give complete protection from the formation of light-struck flavor. Furthermore, it will act as an antimicrobial agent when added to beer. Tetrahop® Gold is classified as a modified hop extract that may be safely used in beer in accordance with the US FDA regulation 21 CFR 172.560 (b) (6).
PRODUCT SPECIFICATIONS:
Description: A yellow to amber colored, aqueous solution of the potassium salts of tetrahydro-iso-α-acids.
Concentration: Standard concentration is 9.0% ± 0.5 of tetrahydro-iso-α-acids by HPLC
pH 8.5 – 11.0
Density: 1.017 g/mL (approximately) at 20 °C (68 °F)
Viscosity: 2 - 10 mPas at 20°C
Solubility: Soluble in pH-adjusted de-mineralized water, and in alcohol
Iso-α-acids: < 0.1%
PRODUCT USE:
Tetrahop® Gold is normally used after fermentation and before final filtration. Utilization of Tetrahop® Gold in final beer can be expected between 55 - 80% depending on the time and efficiency of dosing (kettle dosing is not advisable). The point of addition should be close to a region of turbulent flow, e.g. on the suction side of a centrifugal pump. The dosing pump should be adjusted to deliver Tetrahop® Gold over approximately 70% of the total transfer time. It is advisable to make the addition prior to the final filtration step. Local high concentrations of tetrahydro-iso-α-acids should be avoided and the addition point should be well separated from that of any other additives. Tetrahop® Gold may be added at ambient temperature without prior dilution directly to beer. If dilution is necessary, the use of demineralized water and a pH adjustment to 10 – 11 with KOH is necessary. Do not use sodium bases to adjust the pH of the dilution water – caustic soda or sodium hydroxide form poorly soluble salts with most hop acids.
The amount of Tetrahop® Gold is calculated based on the product concentration and the assumed utilization. Conducting trials at the brewery will determine the correct dosage of Tetrahop® Gold with regard to sensory bitterness and foam enhancement. Depending on the type of beer, Tetrahop® Gold may give 1.0-1.7 times the perceived bitterness of normal iso-α-acids. Tetrahop® Gold should not be left in dosing lines at low temperatures. We recommend cleaning lines and dosing pumps with warm slightly alkaline demineralized.
USAGE CALCULATIONS:
The following calculations are based on the assumption of tetrahydro-iso-α-acids (THIAA) being 1.7 times as bitter as iso-α-acids (IAA). Utilization of THIAA is expected to be up to 70 - 75% when Tetrahop® Gold is used as recommended.
Desired Sensory Bitterness Units = BU
THIAA required in beer (mg/L) = BU/1.7
Dosage THIAA in mg/L (70% utilization assumed) = BU/1.7 x 100/70
Dosage in grams THIAA per hL of beer = BU/1.7 x 100/70 x 100/1000
Dosage amount of Tetrahop® Gold (9% THIAA) in g/hL:
BU/1.7 x 100/70 x 100/1000 x 100/9g/hL = BU x 0.93g/hL
Dosage amount of Tetrahop® Gold (9% THIAA) in mL/hL:
BU/1.7 x 100/70 x 100/1000 x 100/9 x 1/1.015mL/hL = BU x 0.92mL/hL
(e. g. for 5 desired sensory bitterness units 5/1.7 X 100/70 X 100/1000 X 100/9 = 4.7 g/hL (4.6 mL/hL) of Tetrahop Gold are necessary)
FOAM ENHANCEMENT:
Calculate required Tetrahop® Gold as shown above (for foam and cling enhancement we generally recommend Tetrahop® Gold not be added to the final beer at a concentration greater than 5 ppm THIAA). Reduce kettle bittering by an equivalent BU to compensate for the bitterness contribution of Tetrahop® Gold.
LIGHT STABILITY:
Tetrahop® Gold will only provide protection from light-struck flavor if a complete absence of normal iso-α-acids is achieved, therefore no other sources of non-reduced iso-α-acids should exist in the wort or beer streams. Thus for light-stable beers packaged in clear or green glass bottles, all the hop bitterness must be derived from reduced hop acids such as Tetrahop® Gold Redihop® or Hexahop® products. Iso-α-acids (from equipment or yeast) must not be present in the beer. If beta extracts are used as kettle additives, ensure that the concentration of α-acids and iso-α- acids are below 0.2%
PACKAGING:
Normally supplied in high-density polythene containers of 20 kg
STORAGE AND BEST-BY RECOMMENDATION:
Store Tetrahop® Gold in full, closed containers at 15 – 25 °C (59 – 77 °F). Prolonged storage at high temperature will cause deterioration. Tetrahop® Gold performs best if used within 24 months from the time of production if stored as recommended. Opened containers should be used within a few days.
ANALYTICAL METHODS:
The concentration of tetrahydro-iso-α-acids is measured by UV Spectrophotometry (with modified factors) or by the EBC Method 7.9 (HPLC). Details of recommended methods are available on request.