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If there’s one completely new thing I learned from the show Great British Bake Off, it’s hot water crust pastry. I had never heard of the term before watching the show. Although, looking back, I did have some pies made with hot water crust pastry when visiting the UK, without realizing it was.
Pies in the UK are quite a staple in pubs. They tend to be savoury and it’s hearty, good proper food that fills you up. They tend to be encased with a crust quite extensively, more than what I consider is the case on a ‘regular’ pie.
Hot water crust pastry is really easy to work with and you can even make a pin without a tin when using hot water crust pastry. About time we explore hot water crust pastry in some more detail!
What is hot water crust pastry?
Hot water crust pastry is a pastry type used for making pies. As the name says, it involves hot water. The hot water is used to make the dough itself, before baking it.
Other pie crusts are made cold
In most pie crusts you use cold, or even ice cold liquids and fat to make the pastry. The advantage of using the cold ingredients is that you create that flaky crust. The pockets of fat melt in the butter and create all those layers in the crust making it light and crunchy.
This one is made warm
When you use hot water though to make your pastry, you will not have that layered effect. The overall crust will be slightly more dense, but still crispy if you bake it well.
The main advantage of hot water crust pastry is that this dough is strong and can hold its shape. You don’t necessarily need a tin to bake the crust! We’ll come back to why this works in a minute. (In the Great British Bake Off this is always one of the challenges, not an easy one with several of them still collapsing during baking.)
How to make hot water crust pastry
You make hot water crust pastry by melting your fat (often lard or shortening) in water (see recipe below his post). You bring the mixture to the boil and then add it to the flour. This will give you a slightly sticky but very soft, flexible and sturdy crust dough. You only need to knead it slightly for it to come together. You can easy move it about and press it down into or around a tin.
Upon cooling of the pastry the fat solidifies again and the cooked starch (because of the hot water) firms up as well. This results in a sturdy dough that can keep its shape quite well! You can remove it from the tin, but you can also leave it in of course so extra sturdiness.
Science of hot water crust pastry
The hot liquids are what make hot water crust pastry unique. The high temperatures will cause some of the starch to cook and gelatinize. During gelatinization the starch absorbs water and swells up and even breaks apart slightly. This will bind water quite well and is what makes the dough a lot loss crumbly than a dough you would make with cold water.
Challenges of hot water crust pastry pies
Hot water crust pastry pies have their challenges, there’s quite a few things that need to work out well.
First of all, most hot water crust pastry pies are fully encased (especially those baked without a tin since the sides would collapse if there’s nothing holding them up). As a result, not a lot of moisture can escape. Getting a soggy bottom can be quite a challenge, you shouldn’t use too much moist fillings (especially raw fruits & vegetables which will release a lot of moisture once cooking).
Crusts only become crispy if they aren’t too wet (same as for chicken skin). If there’s a lot of moisture in the crust still, it will remain soft.
Leaking & collapsing walls
If you’re baking a hot water crust pastry pie without any tin, there’s a chance the walls might collapse. The dough is quite firm when it’s cold, but once you start filling it it will start to warm up again. This will make it a lot softer. This can result in cracks and leaks in the dough. Working fast is important here, or keeping it cool.
Second, once the pie enters the oven it will become very warm. Whereas the heat will eventually cook the crust, firming it up, it will first just melt the fats and warm the crust without yet cooking it. At this point the crust (as with any pie crust) is vulnerable towards collapse. If you don’t attach the sides to the top well enough, they can just sink down!