Enhancement of Sensory Hop Aroma by Extending the Whirlpool Settling Time
Abstract
Conclusion]This study demonstrated that extending the whirlpool settling time causes hot trub to re-dissolve and can enhance sensory hop aroma.[Content] Traditionally, in the whirlpool process, emphasis has been placed on coagulating and separating hot trub as much as possible and removing lipids and off-flavor precursors.However, hop-derived terpenoid aroma compounds, which are hydrophobic and have high boiling points, are not only volatilized during boiling but are also removed to a considerable extent through adsorption onto hot trub.Therefore, extending the whirlpool settling time promotes the re-dissolution of hot trub and, as a result, can enhance sensory hop aroma.On the other hand, extending the settling time can also cause trub that has once coagulated to re-dissolve, allowing lipids and off-flavor-related components to leach out again.We also demonstrated that isomerization of α-acids begins at around 60-70 °C.This means that isomerization continues during the whirlpool settling process as well.Furthermore, we found that as the whirlpool temperature decreases and the wort temperature falls, the coagulability of hot trub decreases and the coagulation state deteriorates.When separation is prioritized, heat retention or preheating of the whirlpool vessel is effective, and the discussion of whirlpool settling time must be considered not only in terms of time alone but also together with the temperature profile during the process.Accordingly, extending the whirlpool settling time promotes the transfer of hop-derived hydrophobic aroma components while involving "(1) re-dissolution of hot trub" and can "(2) enhance sensory hop aroma and bitterness value"; however, because it may also cause "(3) re-leaching of off-flavor-related components," it is necessary to design the whirlpool settling time and temperature while considering the balance among these factors.
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BibTeX
@misc{kishimoto2026enhancement,
title = {{Enhancement of Sensory Hop Aroma by Extending the Whirlpool Settling Time}},
author = {Toru KISHIMOTO},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15009107/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009107/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Enhancement of Sensory Hop Aroma by Extending the Whirlpool Settling Time
AU - Toru KISHIMOTO
PY - 2026
DA - 2026/09/20
PB - ChemRxiv
DO - 10.26434/chemrxiv.15009107/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009107/v1
AB - Conclusion]This study demonstrated that extending the whirlpool settling time causes hot trub to re-dissolve and can enhance sensory hop aroma.[Content] Traditionally, in the whirlpool process, emphasis has been placed on coagulating and separating hot trub as much as possible and removing lipids and off-flavor precursors.However, hop-derived terpenoid aroma compounds, which are hydrophobic and have high boiling points, are not only volatilized during boiling but are also removed to a considerable extent through adsorption onto hot trub.Therefore, extending the whirlpool settling time promotes the re-dissolution of hot trub and, as a result, can enhance sensory hop aroma.On the other hand, extending the settling time can also cause trub that has once coagulated to re-dissolve, allowing lipids and off-flavor-related components to leach out again.We also demonstrated that isomerization of α-acids begins at around 60-70 °C.This means that isomerization continues during the whirlpool settling process as well.Furthermore, we found that as the whirlpool temperature decreases and the wort temperature falls, the coagulability of hot trub decreases and the coagulation state deteriorates.When separation is prioritized, heat retention or preheating of the whirlpool vessel is effective, and the discussion of whirlpool settling time must be considered not only in terms of time alone but also together with the temperature profile during the process.Accordingly, extending the whirlpool settling time promotes the transfer of hop-derived hydrophobic aroma components while involving "(1) re-dissolution of hot trub" and can "(2) enhance sensory hop aroma and bitterness value"; however, because it may also cause "(3) re-leaching of off-flavor-related components," it is necessary to design the whirlpool settling time and temperature while considering the balance among these factors.
ER -