At Soshinsen, all our Maguro come Super Frozen
The process of Super Freezing brings the temperature of a fish down to -60°C.
This stops the natural decay through the prevention of dehydration and spoilage, and effectively kills of all bacteria that presents itself on the fish. Once defrosted, the fish will retain the freshness that it possessed before freezing. Thus, without having to add any preservatives, we can assure you that our Maguro is of high quality.
The Super-Freezing process
Step 1: This process begins far away from us, on the fishing boats from which our Maguro is caught on. These fishermen only use long line methods.
Step 2: Upon catch, each Tuna is immediately gilled, gutted and bled out using a special method which prevents the fish from feeling any pain and going into rigor mortis.
Step 3: The whole Maguro is then placed in super freezers on board these fishing boats, where their internal temperature will reach the optimum low temperature of -60°C. This freezing process takes about 2-3 hours.
What is the thawing process like?
The thawing process is straightforward, and can be done easily at home if you follow this set of instructions. This can be done through the use of the "Salt Water Method". This method has been used since traditional Japan and continues to be used today.
Step 1: Run Maguro under running water to remove unwanted bits of Maguro that might have stuck on the skin and sides of the tuna
Step 2: Prepare a water bath with 3%-4% salinity. (E.g. For every 1L of water, add in 30g of Salt)
Step 3: Wash and soak Maguro with salt water for 5 minutes. This covers and seals up any small lacerations on the slab of Maguro that was caused during the slicing of the frozen whole Maguro.
Step 4: Remove the fish from the Salt Water and wipe it dry. Then, place it on a tray lined with kitchen towels. Place the entire tray in the fridge to thaw for 5 hours. Do make sure to check on it from time to time to ensure that there is no build up of water to prevent a deterioration of the Maguro quality.
Step 5: Make sure you have a sharp knife and start slicing it!
Note: After the Maguro has been thawed, it should be consumed within a day for optimal freshness.