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To bake tender pie crust, scones, or biscuits, I've always heard that the dough should be handled and mixed as little as possible. The more it's pushed around, the more the gluten develops.

There's usually two steps (first cutting fat into flour, then mixing in milk or water). I was wondering if the gluten development starts from:

  1. as soon as I do anything (when I cut in shortening and butter)
  2. once the liquid is added
Erica
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1 Answers1

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Wheat and (other grains) contains the two protein classes gliadin and glutenin, which together can form the composite protein gluten.

This process requires water and is influenced by

a) the amount of water available and
b) the mechanical process of kneading.

Thus a strong gluten network (as desired in bread baking) is acchieved by either

  • dilligent kneading wet flour for a certain time (-> window pane test)
  • or a higher hydration (= wetter) dough and longer resting times, aided by the -> stretch and fold technique.

On the other side of the spectrum are flaky and crumbly goods like shortbread , pie crust and bisquits - here you try to avoid excess gluten formation. There are two ways to do this, usually employed both:

  • Adding fat to the dry ingredients before adding any liquid.
    The fat (butter, oil, lard...) "protects" the flour from "getting wet" once liquid is added, thus inhibiting gluten formation.
  • Using only a limited amount of liquid and no kneading and gentle handling of the dough after the addition.

So to answer your question:
There is only very little water in your butter which could trigger the development of gluten. Therefore you can "rub" your butter/shortening/... in without much influence on gluten formation. Once you add liquid (egg, ice water, milk, depending in your recipe), you need to be careful.

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Stephie
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    This is pretty much what I suspected, but wasn't sure if the process of making small crumbs of flour-fat would cause unwanted gluten formation -- and the scientific explanation is excellent :) Thanks! – Erica Oct 25 '15 at 18:59
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    @Erica you can also try using vodka in lieu of (or in combination with) water or milk in pie crust, it provides moisture so the dough is easier to handle, but alcohol doesn't form gluten. And most of the alcohol evaporates during blind baking. – Dan C Oct 25 '15 at 20:10
  • Heat also influences/inhibits gluten formation - there are very old methods for pie crusts that use boiling water (and optional fat emulsified into it)... – rackandboneman Oct 29 '15 at 22:11
  • @rackandboneman could you elaborate, please? Or write a second answer? – Stephie Oct 30 '15 at 04:41
  • "Hot water pie crust" ... the oldest (medieval) style does not use any fat or seasoning, just flour/salt?/ boiling water, making an inedible pastry (not gluten-tough but hard) to (pre)serve the filling in. Modern h.w. crust uses fat (tried, used Alsan brand margarine (interest. Palm+Coconut, common high quality margarine in Germany) for experiments) boiled with some water (did est around 4:1-2:1 in volume - careful there, that can erupt viciously if not stirred!) , then mixed in ,and is definitely very edible if not overbaked - great fresh BUT unlike the medieval version it does not keep. – rackandboneman Oct 30 '15 at 09:47
  • Also, mandarin pancakes and various other chinese breads. Boiling water is used to limit gluten forming. – rackandboneman Apr 24 '18 at 08:51
  • @rackandboneman still thinking that this could make a nice complementing answer...? – Stephie Apr 24 '18 at 09:15