Isomerised hop extract Flashcards
What are isomerised hop products primarily used for?
To add bitterness.
What is Isomerised Kettle Extract (IKE)?
A CO2 extract added to the kettle.
At what temperature is CO2 hop extract heated to during the IKE process?
75-85°C.
What pH range is optimal for isomerisation?
7-10.
What catalyst is added during the IKE process?
Magnesium salts.
What happens after sulphuric acid is added in the IKE process?
The isomerised CO2 extract separates from the liquid.
What is the alternative name for potassium isomerised kettle extract?
PIKE.
What is a key advantage of IKE in beer production?
Precise control of bittering due to standardised iso-α-acid content.
How long does it take for IKE to dissolve in wort?
Roughly five minutes.
What is Isomerised Hop Extract (Iso-extract)?
A liquid solution containing iso-α-acids at a specific concentration.
What is the typical concentration of iso-α-acids in Iso-extract?
Around 30%.
What is the purpose of the base extract in the Iso-extract process?
Used as a base for further products like β-acid extract.
What is post fermentation bittering (PFB)?
Allows increased hop utilisation after fermentation.
What is the potential utilisation percentage of iso-α-acids in PFB?
Over 90%.
Why is Iso-extract not recommended as the only hop product in beer?
It only adds bitterness, lacking other flavour compounds.
What are hydrogenated or reduced hop extracts designed to eliminate?
The formation of lightstruck flavour in beer.
What causes lightstruck flavour in beer?
3-methyl-2-butene-1-thiol (3-MBT).
What is the flavour threshold of 3-MBT in beer?
4-7 ng/L.
What prevents the formation of 3-MBT during beer production?
Reducing weak double bonds in iso-α-acids.
What are the three types of reduced iso-α-acids?
- Rho-hydro iso-α-acids
- Tetra-hydro iso-α-acids
- Hexa-hydro iso-α-acids
What is added as a hydrogenation agent in the production of rho-hydro iso-extract?
Sodium borohydride.
What is the process for producing tetra-hydro iso-extract?
Mixing iso-α-acids with hydrogen gas in a pressurised vessel.
What catalyst is used in the production of tetra-hydro iso-extract?
Palladium.
How many hydrogen atoms are added in the production of hexa-hydro iso-extract?
Six.
What is a key attribute of rho iso-extract?
Concentration of 30%.
What does tetra-hydro iso-extract improve in beer?
Foam stability.
What must be ensured when using reduced hop extracts for light stable beer?
They must be the only source of bitterness.
What happens if traces of iso-α-acids are present when making light stable beer?
They can form noticeable amounts of 3-MBT.
