We found 1.160 Kg (2.5 Lb) frozen Spanish octopus for $10/pound at Mediterrafish. We defrosted it overnight, then cut off the legs and head (already cleaned), tossing the middle containing beak and eyes.
We bagged it with some frozen olive oil, then chilled in the freezer an hour before vacuum sealing to prevent sucking out all the water.
Typical tenderization methods include smashing the octopus on rocks, beating with a mallet or even a daikon. Cooking techniques usually are to bake in a covered pot (to collect liquid and self-braise) at a very low temperature for a long time, or to boil (with the old wives tale addition of a wine cork, debunked by Harold McGee). Boiling would lose any liquid that would be released from the octopus, so we used sous vide to keep the beast immersed in its own liquid while slowly cooking at a low temperature.
Different folks seem to sous vide octopus for 3-8 hours between 74-83c (165-180F), some reporting chewiness at lower times and temperatures. We went with 75c (167F) for 5 hours.
We'd read that octopus releases a lot of liquid when it cooks, and it sure did. Our long fat legs seemed to lose half their length and girth, and the vacuum bag was full of a reddish liquid. We let the bag cool slowly on the counter in hopes the legs might reabsorb some of the liquid, before chilling overnight in the fridge.
The next night, we drained the liquid and weighed the octopus: 315 g. We'd ended up with 27% of the weight we'd started out with -- that jacks up the price for the meal quite a bit! What we figured might feed four or more would not be barely enough for two for dinner. We strained the liquid and will make risotto from it: at least it's not going to waste.
At the barbecue, we brushed the legs and head with olive oil and dusted generously with pimenton, like a pulpo a la gallega presentation. I used skewers to keep the octopus parts from falling through the grates, and grilled for a few minutes a side.
What worked, what didn't
The octopus turned out tender enough, with a slight mucilaginous-ness which may be due to not rinsing off loose skin after cooking. We didn't get the crisp char we wanted at all, and the octopus stuck a bit to the grill: these may be connected, as I didn't scrub and oil the grates.
The skewers worked well at holding things together and removing them to plates quickly.
It's also disappointing that $25 worth of octopus barely fed two people. I'll look around the Asian markets, and our local Brazilian/Portuguese store says they carry it.
Next Time
If I could determine a way to reduce loss to liquid I would, even if I sacrificed a bit of tenderness.
Thoroughly rinse off the loose skin after cooking so we don't have any mushiness on the outside.
Get the coals really hot and close to the grill grates, then clean and oil them before adding the octopus. Use the skewers for cooking again.
