So last week we ran a poll
competition on our Facebook page with an eye-watering prize; almost everybody
chose the wrong answer. The most common misconception was regarding frozen fish for sushi, which will be further explained below.
Poll results. To be fair, the freezing law thing isn't common knowledge.
The question was: “All fish at Kazari HQ is super-frozen to -65 °C. Which of the following is NOT a reason for freezing fish that is to be consumed raw in sushi?”
Option 1.) “It preserves colour”.
Actually, colour is one of the main reasons for using super frozen fish compared with regular frozen fish. At any temperature above -40 °C, oxidation occurs within the flesh of some fish, including Tuna, causing it to become an unattractive dark red colour. This will be better explained in our next blog post. This is also how we keep our Tuna for sushi a beautiful red colour.
Option 2.) “It preserves texture”.
When it comes to frozen fish, texture has always been a concern. This is because with traditional slow freezing, water molecules in the flesh expand and break down texture. Approximately 75% of ice in frozen food forms at temperatures between 0.5°C and –5°C. During super freezing, this temperature range is quickly bypassed thus preserving texture.
Option 3.) “Freezing fish is
a legal requirement”.
There is no arguing with this one. EU law states that any fresh fish for sushi that is intended to be consumed raw must be frozen at below -20°C for at least 24 hours. The FDA of the USA has a similar regulation. Yes, this does fly in the face of traditional Japanese sushi fish, which was eaten raw (and warm) before freezing technology existed to make sushi.
Option 4.) “It preserves flavour” (the correct answer).
Fish flesh develops flavour over time, although texture is compromised. Many of best sushi chefs have their own techniques for aging different species before serving. This is because enzymes start working to produce free amino acids, which are what give sushi fish its flavour. Thus by super-freezing fish and essentially stopping biological time, this flavour development is essentially halted.
So here are some interesting facts about the sushi fish that can be found in all of our sushi making kits.
So that’s that, next time we promise to choose an easier question.
Make sure you check our next blog
post…it’s really cool. If you want a sneak peak we put some photos on our Pinterest board here...