Tetrahydro Isomerized Hop Extract
Tetra-Hydro Isomerized Hop Extract (Tetra) is an aqueous alkaline solution of the potassium salts of tetrahydro-iso-α-acids. It is produced from CO2 hop extract using a patented all aqueous process. Tetra enhances beer foam when used as a post-fermentation replacement for part of the normal bittering. In the absence of normal α-acids and iso-α-acids, Tetra will give complete protection from the formation of light-struck flavor. Furthermore, it will act as an antimicrobial agent when added to beer. Tetra 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).
Description: A yellow, amber colored, aqueous solution of the potassium salts of
Concentration: Standard concentration is 10.0% ± 0.5% of tetrahydro-iso-a-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-a-acids: < 0.1%
Tetra 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 Tetra and Isomerized Kettle Extract (IKE) 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%
Tetra-Hydro Isomerized Hop Extract (Tetra) is normally used after fermentation and before final filtration. The utilization of Tetra in a final beer product 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 Tetra 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. Tetra may be added at ambient temperature without prior dilution directly to beer. If a dilution is necessary, the use of de-mineralized 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 Tetra is calculated based on the product concentration and the assumed utilization. Conducting trials at the brewery will determine the correct dosage of Tetra with regard to sensory bitterness and foam enhancement. Depending on the type of beer, Tetra may give 1.0-1.7 times the perceived bitterness of normal iso-α-acids. Tetra should not be left in dosing lines at low temperatures. We recommend cleaning lines and dosing pumps with warm slightly alkaline de-mineralized water or ethanol after use.
Use Rate Calculations:
The following calculations are based on the assumption of tetrahydro-iso-a-acids (THIAA) being
1.7 times as bitter as iso-a-acids (IAA). The equation below factors in the adjustment in perceived bitterness and is you actual dosing rate. As mentioned for all other brewing products, trials are the best way to determine in-house efficiency and dosing rates for each product. We will assume 70% utilization of THIAA.
Dosage = BU x 0.680
Dosage = milliliters of THIAA to be added per BBL of beer
BU = is the desired amount of bitterness units imparted by Tetra
Note: Use rates may vary depending on the brewing process and the desired hopping level.
** If you would like to change the efficiency from 70%, adjust the 0.70 in the equation.
75% efficiency will change this value to 0.75 and 65% efficiency will adjust to 0.65.
You are going to make a beer and would like to provide all of your bitterness using Tetra-Hydro Isomerized Hop Extract post fermentation. You are brewing on a 30 BBL system and want this extract addition to give you 18 IBUs in your finished beer. Assume 70% efficiency.
Dosage = 18 x 0.680 = 17.49 ml/bbl * 30 BBL = 524.7 mls Tetra
You are going to make an Imperial IPA on your 30 BBL system and would like to provide some of your bitterness from Tetra-Hydro Isomerized Extract post fermentation while utilizing traditional hops throughout the boil. You decide to make a bittering addition, a flavor addition and a final aroma addition at knockout. You will also be dry hopping in the tank. Your target IBU’s for the brew are 100 from which 60 of those will come from the first bittering addition. You decide to split that bittering addition up 60/40 between THIAA and Kettle Hops. Assume 70% efficiency.
Packaged in Square Polypropylene containers weighing 1 kg.
Storage and Best-by Recommendation:
Store Tetra in full, closed containers at 59 – 77 °F. Prolonged storage at high temperature will cause deterioration. Prolonged storage at low temperatures will cause precipitates which are normal and will go back into solution when product is warmed. Tetra performs best if used within 24 months from the time of production, if stored as recommended. Open containers should be used within 1 month.
The concentration of tetrahydro-iso-a-acids is measured by UV Spectrophotometry using ASBC guidelines.
We will be pleased to offer support on the use of Tetra-Hydro Isomerized Hop Extract in brewing. For assistance, please contact our knowledgeable staff at 1-800-952-4873 or e-mail firstname.lastname@example.org