Hot Water Crust Pastry: effects of different ratio of ingredients?

Question

Based on a comment made here Australian Meat (Chunky steak) Pie: loss of Gravy/Sauce after cooling/freezing - Seasoned Advice (which I thankfully read before it was deleted by a moderator), I have been looking into the making of a Hot Water Crust Pastry.

The process itsself seems to be clear.

I swiftly found, however, that the ratio of the 3 main ingredients (flour, water and lard) vary considerably in almost every recipe.

What effect do these different ratios have on the final result?

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Samples found:

The Wikipedia Cookbook:Hot Water Crust Pastry - Wikibooks
suggested ratio:

• water: 100% of flour
• lard : 50% of water

Liam’s Nan’s Sunday Dinner | The Great British Bake Off
suggested ratio:

• water: 38.46% of flour
• lard : 60% of water

Scotch pies recipe - BBC Food
suggested ratio:

• water: 44.44% of flour
• lard : 75% of water

Glasgow Guide: Scottish Recipes: Scotch Pie
suggested ratio:

• water: 45% of flour
• lard : 35% of flour (77.77% of water)

Easy & Authentic Scotch Pie Recipe - Scottish Scran
suggested ratio:

• water: 48% of flour
• lard : 83.33% of water

Scotch Pie Recipe with step by step instructions and photos
suggested ratio:

• water: 51.11% of flour
• lard : 86.95% of water

Answer 1

So, first of all, the method you chose for listing the ratios is not exactly the most effective in depicting the ratios for comparison...

Usually we just list ratios as parts or with the quantities themselves (using g = mL for water is acceptable), makes everyone's life easier when trying to troubleshoot a recipe. Example for the first recipe:

2 flour : 2 water : 1 lard or 170g flour : 170g water : 85g lard

Now onto what should be expected

Pastry crusts in general have 3 basic ingredients: flour, solid fat and water.

Note that I use the term "solid fat" because it is not necessarily lard, it can be butter, shortening, or other fat that's solid at room temperature. Why is this relevant? Your 2nd recipe (Liam's Nan) uses both butter AND lard, so your final ratios look more like this:

2.6 flour : 1.1 solid fat : 1 water or 650g flour : 275g solid fat : 250g water

Doing the maths, there is no much variation between your recipes, all of them are roughly 52-56% flour, 19-23% fat and 21-26% water, except for the first one, which is 40% flour : 20% fat : 40% water.

A crust with a higher water content, like your first recipe, tends to be more elastic before baked, and tougher / chewier after baking, and they can also take a filling that's richer in liquid without getting soggy, and the crusts with a higher fat content tend to be harder before baking and crumblier / flakier after baking, and require a filling that's drier or has the water "bound" with a starch, like cornstarch or flour.

Answer 2

The difference between your Glasgow recipe and the others from Scotland is because the Glaswegians like a soft pastry on their pies, whilst the rest of Scotland seems to prefer a 'Crisper' or 'crunchier' pastry.