Sushi Freezer/Superfreezer?

[iguana1]

As the season approaches I am thinking more about how we can preserve fish better. I know the japanese preserve bluefin at -70 and most sushi fish is superfrozen. I have done some web searching and it appears you can buy a home sized superfreezer (dairei sf 150) for somewhere around $4000. Has anyone else done research on this or have any other ideas? I love the idea of having sushi grade fish year round.

[twofinbluna]

I dont know anything about those mini super-freezers, but I know that the key to the way Japan freezes bluefin is not only the very low temp, but also the short amount of time it takes to get it frozen. That is equally- if not more important- than the actual temp. I would be surprised if you could buy something for the house that can freeze the fish quick enough, but I could be wrong. Just make sure you look into that aspect before blowing 4 grand on one!

[tunatamer73]

I dont know anything about those mini super-freezers, but I know that the key to the way Japan freezes bluefin is not only the very low temp, but also the short amount of time it takes to get it frozen. That is equally- if not more important- than the actual temp. I would be surprised if you could buy something for the house that can freeze the fish quick enough, but I could be wrong. Just make sure you look into that aspect before blowing 4 grand on one!

Do you know how they get it to freeze quickly. Is it dry ice, LN2???? I have been trying to figure this out for a while.

[Double D]

I saw a blurb on TV the other day about a new freezer technology called CAS. It was very intriguing, and the photos they showed of CAS frozen food versus standard was amazing. Doesnt seem like they are made for home use though, or at least I can't find one

Rather than trying to beat these physics, a Japanese technology company, ABI, has developed CAS or Cells Alive System that actually changes the physics of freezing. Using an oscillating electrical field, it causes water molecules to spin (as opposed to vibrate as in a microwave) and stops them from clustering and forming ice crystals that damage cell walls. This spinning motion also artificially lowers the freezing point of water to about -7ºC - when the product reaches this temperature, the electrical field is turned off and it freezes almost instantaneously from the inside out. With CAS freezing, power is no longer a major issue as uniform freezing is achieved. CAS uses 30% less power than conventional freezers, and can be uo to five times faster depending on the product.

http://findarticles.com/p/articles/m.../ai_n16063583/

http://foodreview.ihs.com/news/2006/...on-freezer.htm

[tunatamer73]

DD That is some cool, parden the pun, stuff right there. I am going to seriously look into this. Thanks for sharing.

[southport05]

Tunatamer, at sea, they use blast freezers to drop the temps quickly to I believe somewhere around -30 or -40 degrees. Then I believe they move them into a deep freeze freezer to hold them until offloading.

They do something similar up in Gloucester to freeze packaged herring. Put pallets of the stuff into the blast freezer to get the temp down quick, then move it into cold storage to hold until shipping.

But you're talking big rooms and massive freezing systems.

[twofinbluna]

Do you know how they get it to freeze quickly. Is it dry ice, LN2???? I have been trying to figure this out for a while.

They use special refrigerants and compressors (not to mention better insulation) but they are so uncommon outside of Japan that I do not have much experience with them so do not know the details. I know a guy who will know all about this stuff and will find out from him. Will let you know.

[twofinbluna]

Tunatamer, at sea, they use blast freezers to drop the temps quickly to I believe somewhere around -30 or -40 degrees. Then I believe they move them into a deep freeze freezer to hold them until offloading.

They do something similar up in Gloucester to freeze packaged herring. Put pallets of the stuff into the blast freezer to get the temp down quick, then move it into cold storage to hold until shipping.

But you're talking big rooms and massive freezing systems.

I know they use blast freezers on a lot of boats but not sure if they still use them for fish like bluefin over there. They like to get it down to about -80 degrees for sushi grade fish, which I do not think they can do with blast freezers. There are very few of those super freezers anywhere outside of Japan. I think I heard of one that was built in the US, but thats it. I cannot say for sure if they have adapted the super freezer technology to the boats or whether it is strictly onshore.

They definitely use blast freezers for other fisheries, like herring/macks. They can get the temps very, very low and the fish are frozen very quickly.

Again, I will find out from someone who will know all about this stuff asap.

[iguana1]

I dont know anything about those mini super-freezers, but I know that the key to the way Japan freezes bluefin is not only the very low temp, but also the short amount of time it takes to get it frozen. That is equally- if not more important- than the actual temp. I would be surprised if you could buy something for the house that can freeze the fish quick enough, but I could be wrong. Just make sure you look into that aspect before blowing 4 grand on one!

Twofin - Thanks. I had not considered the 'speed to freeze' aspect of this. I will do some more research. From an engineering perspective it seems the only way to make soemthing freeze faster would be to use a liquid, rapidly circulate air or freeze it in smaller chunks hence with more surface area for heat transfer.

[aloop]

Do you know how they get it to freeze quickly. Is it dry ice, LN2???? I have been trying to figure this out for a while.

I would seriously doubt it's LN2! If it was the fish would shatter into hundreds of pieces once the fish literally dumped on the floor in the auctions houses. LN2 freezes to quick so it's got to be something else! Dry ice is fun to play with!