Strudel Dough.... why the eggs and oil?
If you are familiar with how to make a Strudel not using store bought pastry, its really a special dough. It's not laminated like puff pastry with butter, instead is stretched paper thin to the size of a dinning room table and buttered as its rolled up. Most recipes are very standard, flour, water, salt, egg and a couple of Tbsp of oil.
Here is my question, what is the oil for? I though that fats shorten or cap gluten strands. Since this dough has to be stretched so thin you can read a news paper through it, doesn't the oil make it more likely to tear? Why is it even needed?
What is the egg for? Don't they soften bread? Is it working as a dough conditioner relaxing gluten so that it can stretch or is it making it short so it bakes up flaky?
Good question. I've only done Strudel once or twice (without using eggs - I've actually never heard of adding eggs to Strudel dough), so I am no expert on this. My guess would be that the additional ingredients are mainly supposed to enhance the flavour and maybe mouthfeel. As Strudel dough usually doesn't undergo a long fermentation it is quite "neutral" in its original state, so especially eggs make it appear a little more like fresh pasta or something.
About the oil: I remember that in Emily Buehler's "Bread Science" book there is a short section about the role of fats. If I remember correctly there is a difference between liquid fats like oil and solid fats like butter. Solid fats in certain amounts actually strengthen the dough, whereas liquid fats weaken the dough. This is just a guess, but maybe the oil does only weaken the "elasticity" (springing back when stretched) part of gluten whereas strengthening the "extensibility" (expanding the dough without ripping) part of gluten behaviour. But I could imagine the purpose of the oil doesn't have anything to do with gluten structure. Adding oil to the dough or even more so rubbing the dough balls with oil before stretching it creates a smooth outer surface and protects the dough a little bit from creating sticky or dry spots. So it is easier to stretch out in practice.
So, to sum up, other than saying that the eggs are absolutely not necessary (and probably not part of "original" Strudel at all), I don't really have a good answer myself :).
too much while stretching and makes the dough easier to stretch. Working around the table, pulling the dough a little bit at a time, there is a chance for the thin dough to dry slightly and the thicker edge to relax before coming around to stretch more. Too dry a dough will crack or rip. Once the dough is hanging over the edge of the table, it seems to stretch itself nicely. Flour will lead to bulky doughy spots so the oil in the dough keeps fingers oiled too without adding flour to prevent sticking. The oil will also help the dough maintain its integrity after being rolled up with wet ingredients like cut apples, juicy cherries, sliced tomatoes or fresh cheese.
As far as eggs go, I use the whites in the dough to strengthen protein bonding, the yolk gets used as a glaze on top.
Apfelstrudel mit Mehl, Wasser, pflanzliches Öl, Salz und einem Spritzer Essig und manchmal ein Klecks Butter wird in die Mischung. Aber ich habe nie von Eiern in einem Strudel zu hören.
Apple strudel with flour, water, vegetable oil, salt and a dash of vinegar and sometimes a dollop of butter into the mixture. But I've never heard of eggs in a Strudel.
The oil is for flakiness. Strudel is not bread, it's pastry.
Oh, so the oil sort of fries the dough making it more flakey? What dose the vinegar do?
Vinegar has the opposite purpose of ascorbic acid (Vitamin C). While ascorbic acid strengthens the dough and makes it more elastic, vinegar reduces the elasticity of the dough, which makes it easier to stretch or roll out without springing back. Sometimes vinegar is added to puff pastry / croissant dough so that it can be rolled out with less resistance. Of course it is not necessary.
Thanks for your response!
My memory of high school science is a little rusty, isn't Vinegar another form of acid like vitamin C?
I have made quite a few Strudels and I never used eggs. Just flour, but not bread flour. In German/Austrian slang it is so called "glatt" or smooth, salt a little bit of vinegar and water. And then coat it in oil to rest it.
It needs some practice to really master it though
pull out the dough.
I spent some time going thru some of the strudel videos on YouTube yesterday and literally fell asleep. Some use eggs, some not. Some stretch the dough the size of a table, some roll it out to the size of a tea towel. They vary from paper thin to rather thick. One even used puff pastry! Different strokes for different folks I say. What ever works for you and is enjoyed by your guests. Adding an egg adds more food value and makes the pastry more expensive. The same with butter. Strudel recipe discussions can get real emotional... but one thing I noticed is that after they are mixed up and worked making smooth dough, they sit covered for about an hour before being flattened out. That gives lots of time to cut up ingredients if you hadn't done it already. What is comforting is that if you don't have eggs around, you can still make a strudel. Flours vary, if you can make it without, fine; if you need an egg, use one. Tip: I found that in hot & humid climates, strudel dough can be hard to pull, work in air-conditioning if in the tropics or position a fan blowing not on but above the dough. :)