Pastry doughs seems so easy on paper.
There’s a minimal list of ingredients and the instructions are so straight forward – mix dry ingredients together, add the butter, sometimes add in water or flavourings such as milk, vanilla or lemon rind, then roll out.
But the end results can differ enormously and one wrong turn could result in a soggy base, a shrunken case or in the worst case an inedible flavour.
To get a proper handle on how it all works you have to get a bit scientific and properly understand what each ingredient does.
In simple terms, it’s all about taste and texture.
Michel Suas’ book Advanced Bread and Pastry provides a really in-depth insight into the science behind pastry and this is my simpleton’s version.
Different types of flours are used to create different doughs and it really comes down to the amount of gluten in each. Gluten it should be said early on is the enemy of pastry but the best friend of other doughs like pizza – it creates elasticity and strength, not usually things you want in a light, crisp or crumbly pastry. Generally all-purpose flour is fine to use but some recipes may call for pastry flour.
Fats serve two purposes when it comes to pastry – they are shortening agents (i.e. stop gluten strands from developing by coating the flour) and provide flavour. When it comes to flavour, you can’t beat butter but it also has its downsides due to its low melting point which can make it difficult to work when if it gets too soft. Shortening can also be used, but you will compromise the flavour and upset some purists along the way. It will however be easier to work with and will hold its shape better.
Water is frequently used in pastry dough recipes but you may also see other liquids such as milk, sour cream and buttermilk. The purpose of the liquid is to help form the dough, but also add flavour or work as a dissolving agent for ingredients such as sugar and/or salt.
Eggs can also be considered a liquid and are included in a number of doughs – sometimes in addition to and sometimes instead of water or milk. The proteins in whole eggs coagulate during the baking process and help to create structure which means that egg-based doughs should provide crusts that don’t fall down at the sides or shrink.
Sweet pastry doughs will always include one type of sugar – confectioners (or powdered) sugar, caster (or superfine) sugar or granulated sugar. Again it comes back to taste vs texture – if you use confectioners sugar, you will get a nice smooth dough with the sugar fully incorporated but it will lack taste. On the flipside, granulated sugar will taste great but will be very hard to work with and will result in a grainy dough. The happy medium is caster sugar, but it will depend on the recipe.
Salt is generally used to add flavour and improve shelf life.
Acids such as lemon juice or vinegar can help relax the gluten in the flour and provide flavour.
Even alcohol (vodka in particular) has been used in a number of recipes recently as an alternative to water – this is one I’ll be interested in testing.
Finally, flavour enhancers such as vanilla, ground nuts or spices can also be included.
So that’s the very simple overview of pastry dough theory. The next step is going to be putting it into practice…