FLEX® is a special formulation derived from pure hops, and its use is designed solely to provide bitterness to beer. FLEX eliminates a significant amount of the inert materials that come with the vegetative portion of hops and hop pellets, and thereby reduces weight, handling, and residual hop material that needs to be removed from the wort during brewing. The significant benefits from FLEX include its low viscosity, which allows it to be measured and dosed easily in the brewkettle, and the reduction of hop solids from wort, greatly reducing the process loss associated with the absorption of wort by the hop vegetative material.
FLEX is designed for dosage early in the brewkettle boil and because the product provides hop alpha acids—the same as those found in whole hops and hop pellets—the isomerization of these alpha acids into iso-alpha acids is still necessary by means of the boiling process in the brewkettle.
Switching from whole hops or hop pellets to FLEX will improve the utilisation of the alpha acids for beer bittering, and the brewer can take comfort in knowing that the transition can be made with little or no effect on hop aroma.
USE OF FLEX
Designed for bittering, FLEX should be dosed into the brew kettle near the beginning of boil, much as is done with whole hops and hop pellets. Unlike whole hops and hop pellets, FLEX disperses much more readily and provides a 10 – 20% (relative) increase in alpha acids utilisation as compared to standard T90 hop pellets. In a typical lager brewing process, the upper limit of alpha acids utilisation is about 35% (FLEX to finished beer); hop pellets max out at about 30%
FLEX contains about 65% alpha acids, thereby providing a five-fold reduction in product weight than the pellet dosing equivalent, and an even more significant reduction in volume. As with whole hops and hop pellets, FLEX should be dosed according to its alpha acids content to achieve the desired bitterness in the beer.
Conditions in different breweries vary so widely that no single formula is adequate for all breweries. From information provided by the brewer on hopping rate, type of hops used and hop boiling schedule, a recommended initial dosage rate will be provided by Haas sales/technical personnel.
When replacing hop pellets with FLEX for initial trials, we recommend that the alpha acids kettle dosage be reduced by 10 to 20%.
FLEX is produced with a target alpha acids concentration of 65%. Standard dosing calculations typically used for alpha-to-beer bitterness levels should be used for FLEX, taking into account differences in utilisation and using the alpha-acids content listed in the FLEX certificate of analysis. As a general guideline, using the 65% FLEX concentration and 30% bitterness utilisation, an initial trial dosage is calculated to be 6.0 grams of FLEX for every 10 BU desired in one barrel of beer (= 1.174hL beer). This equates to 10IBU when dosing 0.05g per Ltr. Of course, actual utilisation may differ, and adjustments are normally required.
Full product spec sheet from Barth Haas : FLEX-Best Practices