If you have ever had a deep or passing interest into the reason why things happen to food when we cook it, cut it, process it, freeze it or mix it then I would recommend reading Harold Magee, an American author whose interest and insights in to food and its science have influenced some of the world’s greatest chefs. It was Harold that influenced Heston Blumenthal, for example, to ask the question “why are we taught that searing meat ‘seals’ it when there is no scientific evidence to suggest that this actually happens’.
I think there are a lot of mythologies about food preparation and cooking that have and are still being taught in cookery, and personally I am interested in understanding why things happen so I can cook by design rather than just relying on being told “that is the way it is.”
One such enigma is the cooking of octopus, squid and cuttlefish (the cephalopods) and why they are sometimes delicate and tender and on other occasions are like chewing on a sphere of elastic bands. There is so much advice out there on how to make them tender, much of which is more hearsay than having any scientific or practical basis to them; salting them, blanching in boiling water, adding a wine cork to the cooking liquid, to name a few.
A cephalopod has no skeletal structure (unlike fish) so its muscles have to work harder to support its structure, and when muscles work harder they become tougher which means they need to be broken down during cooking in order to be tender. The question is how long, and in what do you cook it?
McGee experimented on octopus using a number of techniques such as soaking it in vinegar to dissolve the connective tissues, which worked but left the meat very fibrous and therefore tough; and brining it in a 5% salt solution for a couple of hours and then simmering in plain water, which seemed to produce tender meat but removed flavour from the octopus.
McGee’s investigation also suggested that the connective tissue in octopus needs heating to about 55 deg C (130 deg F) in order for it to break down in to gelatine. This is similar when cooking beef steak, for example. But cooking at this temperature alone will not break down the fibrous muscles of the cephalopod, as these do not start breaking down until the temperature hits 80+ deg C. As a cephalopod contains a high level of water in its structure much of the flavour of the creature is in the water. Therefore, if the creature can be stewed in its own juices for a few hours at a temperature high enough only to break down the tough fibrous structure, and not overcook it, then three things will happen. Firstly, the meat fibres will break down and therefore become very tender. Secondly, as the cephalopod has been cooking in its own juices it will be incredibly flavoursome. And thirdly, you are left with a beautifully flavoured gelatinous jus.
But this is not the end, as there is another way of cooking squid, cuttlefish and octopus that also leaves it tender. That is is to flash fry i.e. fry it very quickly. This works best with smaller cephalopods, and the theory is that quickly frying the meat doesn’t allow for the muscles to toughen.
So to conclude, if using the long method my recommendation, based on experimentation that I have done, is to blanch your cleaned squid, octopus or cuttlefish in boiling water for 20-30 seconds depending on size and quantity. Drain, and then add to a dry pan put on the lid and then let it stew in an oven at 90 deg C (195 deg F) for a few hours until tender. The time will be dependent on the quantity and size. For example, I cook a kilo of baby octopus for about two hours. A 2 kilogram whole octopus may take 4-5 hours.
For quick frying, cut your cleaned octopus, squid or cuttlefish is into bite sized pieces (baby octopus is fine whole) and then fry in a hot pan with grapeseed oil (or similar non-fragrant cooking oil) for 20-30 seconds, ensuring that the contents are agitated to encourage even cooking.
Using both ways I have had wonderfully tender results whether the produce has been caught fresh or has been previously frozen.