Tuesday, 13 October 2009

Scotch Eggs

A while back, my dad spent quite a while telling me that the perfect boiled egg was all about heating the white to a certain temperature, and that if you kept it at that temperature, it would never over-cook. As I've been reading more about the science of cookery, I've found that my dad was correct - an egg cooked at 65C will have a set white and a creamy yolk.

I've also been intrigued by the rise of the scotch egg from Greg's abomination to acceptable gastro-pub fare. They always seem to have a runny yolk, so maybe it was time to apply science to snacking.

Here comes the science bit!

Egg Number 1
Initially I thought the easiest way to keep an egg at 65C without using a fancy-pants waterbath (I don't even have enough worktop space to justify a stand mixer, let alone an water circulator) was in the oven. Although the oven was labeled 60C, it didn't seem particularly hot in there. I could comfortably put my hand in the oven and move the racks around without it burning. The oven thermometer starts at 100C, and the needle was hovering just under this, so I left an egg in there for about 45 minutes.

After the egg had cooled down a bit, I cracked it open. It wasn't firm enough to peel and so in that respect was an epic fail. However, I scooped the egg out of the shell and ate it, and it was amazingly delicious. The yolk was runny and rich, and the white was cooked but still creamy and soft. The only way it could have been better was if there had been some buttered soldiers to dip in it.

Egg Number 2
Next up I decided to try a water bath. Using a sugar thermometer, I heated a saucepan of water to 65C. I was surprised to find that by putting my hob on the lowest setting, that I could maintain this temperature very easily. I occasionally added a little cold water if the temperature started rising, but I only had to do this about twice in the hour or so that I cooked the egg for.

I cracked it open, and initially was quite pleased - the white was set enough to be able to peel the egg, but still wobbly enough to suggest that the yolk would be runny. However, as I continued peeling, it became obvious that the egg was far too fragile to put in to a scotch egg. As I took off the last pieces of shell, the egg collapsed completely.

By some fluke of science, I'd created an inverted egg. The yolk was completely set, and was like a little orange pebble in a pile of white gooey jelly. I ate this egg too. It wasn't as tasty as the first one, but the yolk, while set, was still moist. I'd be quite interested in using this method again to create set yolks that could be used as a garnish or as a component in a dish.

What had happened was that the yolk proteins had set at 65C, as had some of the white proteins. However, one of the proteins in the yolk doesn't set until 80C, so this egg obviously had a higher ratio of this high temperature protein and thus the white was still quite runny.

Egg Number 3
By this point, the leftover sausages that I was planning to use for the scotch eggs were dangerously close to their use-by date. So I wimped out and put two eggs in a cold pan of water, brought them to the boil, and simmered for 8 minutes. They were pretty standard hardboiled eggs.

In future, I think I'd go for a two stage process to find the perfect peelable boiled egg. First a lovely bath at 63-64C, to firm up the white, but keep the yolk runny. Then a quick dip (1-2 minutes) in a 90C bath to firm out the outer layer of the white, so it's possible to peel it without it falling apart. Then maybe a quick shock in iced water to ensure they don't over cook. Hmmm, several different baths and a peel, sounds like a day at a spa hotel.

Baked Scotch Egg

The actual scotch eggs were fairly simple to make - mash up a load of sausage meat (about 2 sausages per egg) and wrap this around the boiled egg. Then roll the egg in some seasoned flour, some beaten egg, and then breadcrumbs. I seasoned the breadcrumbs with a little cayenne pepper to give them a bit of a kick. As you can see from the photos, my wrapping wasn't entirely even, but that wasn't too much of a problem.

Uneven but tasty

As with most Scottish items, a proper Scotch Egg is deep fried. I didn't really want to do this, so I baked them at 200C for 30 minutes, and finished them off in the frying pan to get the breadcrumbs crispy. I think the sausage meat insulates the egg quite well, as when I finally got to scoff the eggs they yolk was still quite moist and not overcooked. They were also delicious later on when they'd been chilled for a while. Even though I'd baked them, you could feel the cholesterol destroying your arteries as you chewed. Perhaps this is not the recipe to repeat until I perfect it...


Nora said...

Wow, what exhaustive and scientific research - well done! The final result looks delicious, though. Possibly not an item to be eating every day, as you say, but I think I might have to try making a Scotch egg one of these days. Might be too lazy for all the different baths, though!

Lizzie said...

After eating a venison scotch egg with a gloriously runny centre, I asked how it was done. "the egg is cooked for only 7 minutes". That's all I got out of them...

Jenny said...

Nora - lots of different water temperatures are fun but time consuming! Worth it if you have a weekend and several eggs to spare, but I agree, probably not for "regular" cooking!

Lizzie - the infamous venison scotch egg was part of the inspiration for this. Do you think the 7 minutes refers to the initial boiling or the deep frying time? Once I've been to the gym enough to get rid of this one i'll try a 7min boil!

Chele said...

Wow - that's dedication to the casue. They look fantastic though ;0)

Gemma @ Distracted Gourmet said...

Ah, what a scientific approach! I've been dying to make Scotch eggs for ages! They're so delicious.

them apples said...

That's interesting stuff. I've never thought about the science behind boiling an egg - it's all a bit too Heston for me...

Having said that, I'm very good at making a hard boiled egg, not so good at hitting that firm white, creamy yolk nirvana.

Scotch eggs have always fascinated me. It's true, as you allude, that the worst versions are absolutely appalling, a culinary crime against both the pig and the hen, but done properly, with good sausagmeat and plenty of herbs, they're an utter joy. A point of order, though - they must, must be deep fried.

Now if you'll excuse me, I've got a jam thermometer to find...

Jenny said...

I am a bit scared of deep frying, but I guess I'll have to conquer that one day.

I'm not into scientific cooking as a day to day thing, but it's quite fun for a weekend project. Plus I am a nerd and enjoy finding out how food works!