Tuesday 21 July 2015

Duck eggs... and how to sous vide them

Eggs. Duck eggs.
That's an egg. Specifically it's a duck egg. I now know more about duck eggs that I ever thought possible. I know they are 30% larger than a hen's egg (always hen, not chicken, strange) so you should cook two duck for three hen. That little white, springy thing so detested by Belinda is called a chalaza (plural: chalzae) and is merely part of the albumen scaffolding, keeping the yolk centred in the egg. It has two contra-twisted threads. Quite clever (but still disgusting, according to my wife). Duck has much more fat and protein. There are three types of white albumen which is contains different proteins to hen's so cooks differently. If it's zinc or potassium you want, walk not further. Duck's are the eggs for you. I care about none of the above. What does matter is a duck egg has a much larger yolk, which, let's face it is what an egg is about, unless you're baking with it. What also became important is the little known fact that duck eggs have harder shells and much tougher inner shell membranes.

Waiting for an egg.
I wanted to sous vide duck eggs to serve with my new asparagus starter. Sous vide meaning cooked in a water bath of any temperature, not just boiling. On instructional videos, I watched many chefs place eggs in the water without protecting them. Sod that. I bagged mine first. What if they cracked in the bath? I'd have barely set albumen all over my impeller. That would not do.

The asparagus dish works well with hen but they are too small. There's not enough yolky goodness. I had the idea of serving the eggs on the table in egg boxes - kept pristine for the occasion. It would be a fun bit of table theatre for guests to crack the eggs into a nest of buttered asparagus and a toasted rosemary crumb. A kind of make your own hollandaise. And it was. It works. There's no horror story here sorry.

The 70 minute egg. Nope.
The issue was the temperature and the timing. All the sous vide recipes I found were for hen's eggs. If I wanted a 'poached' egg I'd always done them for 13 minutes at 75°C but if you do this with a duck you harden the inner membrane which then sticks to the white albumen making it almost impossible to:
a. break the egg and
b. nothing comes out when you do.
The egg sits in the shell, sniggering at your ineptitude. Stupid cook!

So I tried many variations. 70 minutes at 64°C. Yup! Nooo. Yuk. Yes, it was cooked but way too (I have to say it) snotty. Who like that texture? Apart from my mate Paul Mari, who I suspect would neck them raw. Also, having such a long cooking time is impractical in the kitchen. I can't have guests waiting an hour while I cook an egg! But I can't start cooking until they all arrive; people sometimes are delayed. So what temperature delivered a decent texture without the recalcitrant membrane? 

It's 69°C. Cook your duck egg, straight from the fridge, for 20 minutes. And that's not a rounding off. I tried 27, 25, 24 and 22. Fabian and I love a poached egg. But maybe less so this week. What with serving guests at the weekend, I went through 40 eggs in five days. 20 minutes at 69°C. Delicious - at least for the first ten times.

Egg in action - being eaten.


  1. Very nice. 69C for 20 min, followed by a hold at 50C if needed works very nicely. Thank you!

  2. Ok followed your recipe perfectly but..... I could not break that membrane. So I had lots of little egg pieces on a lovely egg but totally covering the egg. Any thoughts? Should I have plunged them into a bowl of ice water?