QSF ultra-low temperature
quick freezing

Quick Super Freeze. Fresh food is brought to a core temperature of −55°C within 30 minutes, at −60°C to −80°C. Cold energy recovered from LNG at −162°C is the base refrigeration for both freezing and storage, with −60°C electric freezers running alongside it.

How freezing damages food

Freezing damage occurs in the maximum ice crystal formation zone, between −1°C and −5°C. Water inside and around the cells forms ice crystals there, and the longer the product spends in that band, the larger those crystals grow and the more they rupture cell membranes. Ruptured cells release moisture, water-soluble nutrients and flavour compounds as drip during thawing.

Conventional freezing takes roughly 150 minutes to cross that band. The QSF process crosses it in about 10 minutes and reaches a core temperature of −55°C within 30 minutes.

Conventional freezing −20°C
QSF ultra-low temperature −60°C
Ice crystal size
Ice crystal size — Conventional freezing −20°C
Crystals grow large, leaving wide voids
Ice crystal size — QSF ultra-low temperature −60°C
Crystals stay small and evenly distributed
Cell structure
Cell structure — Conventional freezing −20°C
Tissue tears and gaps open between cells
Cell structure — QSF ultra-low temperature −60°C
Tissue density is retained

From the Gyeongnam QSF information memorandum. The same raw material was frozen under each condition and sectioned for comparison.

15°C 0°C −20°C −40°C −60°C 0 30 60 90 120 150 180 Elapsed time (minutes) Conventional freezing · 150 minutes in the ice crystal zone 10 min Ice crystal formation zone −1°C to −5°C Eutectic point −55°C QSF −55°C within 30 minutes Conventional

Seven things that do not happen at −60°C

01
No protein denaturation
Taste and aroma retained
02
No oxidation
Rancidity and spoilage prevented
03
No drip on thawing
Nutrients retained
04
No cell structure damage
No additives required
05
No moisture sublimation
Freshness retained
06
No separation of water and solids
Long storage, texture retained
07
No bacteria or anisakis
Sterilisation and parasite kill

The eutectic point, and what it means

The eutectic point is the temperature at which all water and solutes within the food are frozen. For fish and meat it falls between −55°C and −65°C. Below it, unfrozen water is minimised and enzymatic reactions and fat oxidation are strongly suppressed. Conventional freezers never reach it — which is why quality continues to deteriorate even while the product remains frozen.

Drip loss3% or less (conventional frozen: 5–25%)
Quality retention3–5× conventional frozen
ColourMyoglobin oxidation suppressed below −50°C
AdditivesNone used

Refrigeration source and energy independence

TWO COLD SOURCES
Recovered LNG cold energy
−162°C → −95°C refrigerant
LNG from the terminal passes through a heat exchanger to produce a refrigerant at −95°C. This is the base refrigeration for both freezing and storage.
−60°C electric freezers
Solar · ESS · fuel cells
Run on self-supplied power. They reinforce the stages where heat has to come out fast and the hours when the load peaks.
Both sources feed both uses
↓
Blast freezing chambers
−60 to −80°C
Cold stores
held at −60°C
BOIL-OFF GAS LINE
Boil-off gas
After heat exchange
→
Hydrogen fuel cell
Power and heat
→
Power, self-consumed
Reduced grid dependence
Hot water recovery
105°C
Drying and smart farm
The two cooling sources work together rather than separately. Cold energy recovered from LNG is the base refrigeration, fed to the blast freezing chambers and the cold stores alike; −60°C electric freezers run alongside it, reinforcing the stages where heat has to come out fast and the hours when the load peaks. Solar generation, battery storage (ESS) and fuel cells supply the electricity, so running at −60°C costs almost nothing in energy and the storage temperature holds through a grid outage.
LNG and refrigeration system diagram
LNG and ultra-low temperature refrigeration system diagram

Because the cold energy itself carries no electricity cost, ultra-low temperature freezing becomes viable for seafood, meat and produce — not only for high-value species.

Published evidence

Eutectic point of fish and meat: −55°C to −65°CFood Refrigeration and Freezing (2014)
Superior quality of lamb frozen below −60°CHong et al., Korean J. Food Sci. Anim. Resour. 38(5), 2018
Optimal freezing rate for meat at −50°CGrujic et al., Meat Science 33, 1993
Prevention of myoglobin browning below −50°CScience and Technology of Meat Products (2017)