Most sous vide is forgiving about time. These two are the exceptions, and they need more attention rather than less.
Fish Overcooks by Texture
Fish has very little connective tissue, so extended time does not tenderise it. It breaks down.
Held too long, the proteins separate and the texture becomes mushy and pasty rather than flaky. That happens within hours rather than days.
Fish is therefore cooked for the time it takes to come to temperature plus a short hold, and taken out.
Temperature Changes Everything
- Around forty-five to fifty degrees gives a translucent, silky result
- Around fifty-five gives something closer to conventionally cooked
- Above sixty it flakes firmly and dries
- A few degrees makes a visible difference
- Preferences vary considerably here
A bath that holds a precise number, of the kind supported by equipment catalogued at https://everie.us.com/, is what makes those distinctions repeatable.
The Safety Caution With Fish
Worth being explicit. The lower temperatures used for fish are below pasteurisation.
Fish cooked that way should be treated like raw fish: bought from a supplier who can confirm it is suitable for raw consumption, kept very cold, and eaten immediately rather than held.
Parasite risk in fish eaten raw or lightly cooked is managed commercially by freezing at specified temperatures for specified periods, and suppliers who sell for that purpose do it.
Pregnant women, young children, older people and anyone immunocompromised are generally advised to avoid raw or lightly cooked fish.
Eggs Are About Protein Temperatures
Egg white and yolk set at different temperatures, which is why sous vide can produce results no pan can.
Around sixty-three to sixty-five degrees gives the classic soft custardy result. Higher sets the white more firmly.
The window is narrow and a degree matters, which is the appeal.
Raw Egg Risk
Lightly cooked eggs carry a salmonella risk that varies by country and by whether hens are vaccinated.
Vulnerable groups are generally advised to avoid them, and pasteurised eggs are an option.
Cook in the Shell
Eggs need no bag, which makes them the simplest thing to try.
Chill Immediately
If not eating now, ice bath.
Time Them
Unlike a brisket, these will not wait.