ISOHOP® HOP EXTRACT
Intended to improve brewer’s control over bitterness, Isohop® Hop Extract naturally acts as an antimicrobial agent when added to beer. Standardized to 30% iso-α-acids, it’s produced from hop extraction and designed to replace kettle bittering hop and improve hop utilization.
DESCRIPTION:
Iso-α-acids are the native bittering acids found in traditionally hopped beer. Isohop® is a standardized solution of iso-α-acids (30% w/w) produced from CO2 hop extract using an all-aqueous process. Isohop® is
used to replace kettle bittering hops to improve hop utilization or to adjust bitterness in beers that may
have been under-hopped in the kettle. For precise control of beer bitterness, Isohop® should be added
post-fermentation to adjust the bitterness of the beer to the target bitterness units (BU). It may also
provide an economic alternative to kettle hopping when performing high-gravity brewing. When hopping
does not go according to plan, Isohop® will help to get back on target. Isohop® will contribute to foam
stand and cling similar to that of traditional bitter hopping (whole hops, pellets, or CO2 extract). Isohop®
will also act as a natural antimicrobial agent when added to beer. Isohop® provides a very good utilization
along with comparatively low costs. Isohop® is classified by the U.S. FDA as a modified hop extract that
may be safely used in beer in accordance with US FDA regulation 21 CFR 172.560 (b) (2-5).
PRODUCT USE:
Isohop® is normally used after fermentation and before final filtration. Utilisation of Isohop® in final beer is typically between 60 - 90% depending on the time and efficiency of dosing. If Isohop® is used in the brewhouse, utilization may be expected at 50 - 60%. The preferred point of post-fermentation addition is close to a region of turbulent beer flow, e.g. on the suction side of a centrifugal pump. The dosing pump should be adjusted to deliver the Isohop® over approx. 70% of the total transfer time. It is advisable to make the addition prior to the final filtration step. Local high concentrations of iso-α-acids should be avoided in the beer stream and the addition point should be well separated from that of any other additions. Isohop® may be added at ambient temperature without prior dilution directly to beer. Dilution is not advised, but if necessary, the use of de-mineralised water and a pH adjustment to 9 - 10 with KOH is recommended. Do not use sodium bases to adjust the pH of dilution water; caustic soda or sodium hydroxide form poorly soluble salts with most hop acids. The amount of Isohop® needed for dosing is calculated based on the product concentration and the assumed utilzation. Conducting trials at the brewery will determine the correct dosage of Isohop® in regard to sensory bitterness. Isohop® will give similar bitterness as that of traditional iso-α-acids. Following dosing, we recommend cleaning lines and dosing pumps with warm slightly alkaline demineralised water or ethanol immediately after each use.
Usage Calculations for Bitterness Adjustment: The following calculations are based on an assumed utilization of 80%. (IAA = iso-α-acids).
Desired Sensory Bitterness Units = BU
Dosage IAA in mg/L (80% utilization) = BU x 100/80
Dosage in grams IAA per hL of beer – BU x 100/80 x 100/1000
Dosage amount of Isohop® (30% IAA) in g/hL:
BU x 100/80 x 100/1000 x 100/30 g/hL = BU x 0.42 g/hL
Amount of Isohop® (30% IAA) in mL/hL:
BU x 100/80 x 100/1000 x 100/30 x 1/1.075 ml/hL = BU x 0.39 mL/hL
(e. g. for 5 desired sensory bitterness units 5 X 100/80 X 100/1000 X 100/30 = 2.1 g/hL 30% Isohop® is
necessary if utilisation is 80%)
PACKAGING:
Isohop® is normally supplied in high-density polyethylene containers of 20 kg. Larger package units are
available on request.
STORAGE AND BEST-BY RECOMMENDATIONS:
Store Isohop® in full, closed containers at 2 – 8 °C (36 – 46 °F). Prolonged storage at high temperature can
cause deterioration. Isohop® 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.
SAFETY:
Any material coming into contact with the skin should be washed off with soap and water. For more
information, refer to the relevant Safety Data Sheet (SDS).
ANALYTICAL METHODS:
The determination of iso-α-acids comprises three types of methods, the specific measurement of iso-α-
acids by means of HPLC, spectrophotometric or conductometric methods. In regard to the
spectrophotometric method, please note that the optical density multiplication factor in the formula
needs to be adjusted from 50 to 70.
• EBC 7.8 for Iso-α-acids, α-acids, ß-acids by HPLC
• EBC 7.9 for Iso-α-acids
• ASBC Hops-16 (Iso-α-, α-, and ß-acids in Hop Extracts and Isomerized Hop Extracts by HPLC