Sous vide eggs - how to get a perfect soft-boiled egg?

Use fresher Grade AA eggs, this minimizes the amount of thin albumen. If this doesn't work you could perhaps try boiling it briefly when it's done cooking via sous-vide. I'd start with 60 seconds in boiling water, and going up from there to find the proper timing. I've never done this, but the boiling water should serve to quickly cook the runny whites.

According to the egg chart in this post this is an issue with eggs cooked sous vide, as the white sets at a higher temperature than the yellow. You could probably solve this by cooking the eggs at the lower end of the spectrum, say 61ºC and then just before you need them put them in a higher temp bath for a few minutes say 66ºC for 5 mins.

Obviously you'd need to experiment to get this right. The above chart suggests cooking at 62 then dipping in simmering water to get a traditional egg. Not sure how long you dip for though. Trial and error I suggest.

I swear I've seen a post about this somewhere, but can't for the life of me find it now.

EDIT:

the post about perfect eggs was on a different site. the most interesting stuff in there is in the comments not in the article itself though, and it starts about this comment which gives a technique for getting perfect soft boiled eggs over a long period of time.

1. In a filled dual chamber water bath, set the left hand side to 90°C and the right hand side to 55°C [place a lid on the left side]
2. Once the bath is up to temperature, place [66g free range eggs] into the waterbath set at 90°C. These eggs need to be cooked from room temperature [20°C] and re-cover with the lid
3. Immediately start a timer for [7:30mins]
4. Once the timer has gone off, immediately lift the eggs from the left side chamber, and place into the right hand side, set at 55°C
5. Allow eggs to remain in the right side bath for a minimum of 5 minutes.
6. The eggs are now ready to serve ‘Soft Boiled’
7. The eggs will remain the same upto 4 hours after placing into the 55°C bath.

Another solution offered by a comment further down is:

I find if I sous-vide eggs at 64.5C for an hour and them crack them open, the yolk is perfect but the egg white is sometimes less set than desired. Very easy resolution, a blast with the propane torch fixes this quickly and the wonderful custard egg yoke stays constant insulated by the now firmer egg white.

Interesting. Lets look at what McGee has to say about this. Egg whites begin to coagulate at 63ºC (145F), become 'a tender solid' at 65ºC (150F) and continue until 80ºC (180F). Egg yolks start to thicken at 65ºC (150F) and settle at 70ºC (158F).

Sooo... get the temperature a little higher 66ºC, 67ºC, until your egg is perfect for you. But remember there are some albumen that are not going to settle until you reach yet higher temperatures.

Why don't you just steam the eggs for 5-6 minutes with the lid ajar. That should give you a mollet egg. Semi liquid yolk and firm white.

I don't have an explanation for it, but I have reason to believe that the white breaks down after being held at temperature for some time. I attempted to do a "perfect" egg by placing 6 eggs in a water bath at once and removing them after different durations. After about 45 minutes the white was firm and the yolk was slightly thickened. As time went on, yolks started getting thicker and whites turning out more liquid.