While most of my recipes focus on Food as Medicine, every chef should understand the science behind classic baking. This lemon meringue pie masterclass explores the chemistry of pastry, curd and meringue, helping you become a more confident cook by understanding why each technique works. Whether you’re studying cookery or simply love baking, these principles will improve every pie you make.
For the pastry
To make perfect shortcrust pastry, work quickly and have all your ingredients and equipment ready before you begin. If you’re making pastry by hand, it’s important to consider the temperature of your kitchen. In subtropical climates like my home in Byron Bay, warmth and humidity can soften butter very quickly.
Because cold butter is essential for a light, flaky pastry, keep it well chilled until the moment you use it. As the pastry bakes, the cold butter creates pockets of steam that help produce a tender, crisp texture. If the butter becomes too soft before baking, it blends more completely with the flour, encouraging greater gluten development and resulting in a tougher pastry.
Before beginning, allow the whites to stand at room temperature for 30 minutes so they will reach their full volume during beating. Within the white of the egg lies a form protein called albumin. When room temperature egg whites are beaten they form air bubbles due to an ‘imbalance of forces’. In the case of meringue, the air bubbles in the foam grow when heated. For a Pavlova, longer baking in a slow oven is required to dry out the foam and crisp the meringue.
For many years I have always added a pinch of salt to meringue to enhance its flavour. The addition of salt has two other effects on meringues as well. First, salt promotes the coagulation of proteins, which means you have to beat the egg whites longer to unwind the bunched up (coagulated) protein strands and stretch them into the thin films that encase air bubbles and create foam. Second, if added too early, it decreases the stability of the beaten egg whites, which in turn weakens the protein network that forms the structure of the meringue.
As a child learning to cook from the age of six, my first fascination with food was the mighty meringue. My Learn To Cookbook guided me through a step-by-step process to make meringues, even suggesting a few drops of cochineal for pink ones.
So inspired by this I made my first hot pink Pavlova. I had no beater, just a whisk so my six-year-old arms whipped furiously. Needless to say it did not rise much. The egg foam was nowhere near eight times fluffier!
PrintLemon Meringue Pie Masterclass: The Science Behind the Perfect Meringue
Master the art of classic lemon meringue pie with this step-by-step baking masterclass. Learn the science behind buttery shortcrust pastry, silky lemon curd and perfectly glossy meringue from chef and nutritionist Sam Gowing.
Ingredients
For the pastry
1/2 cup self-raising flour
3/4 cup plain flour
1 tablespoon icing sugar
120g cold butter, grated
1 large egg, cold
For the meringue
3 large egg whites
3/4 cup caster sugar
Pinch salt
Instructions
- Preheat oven to 180°C (160°C fan-forced)
- Place the self-raising and plain flours, icing sugar and cold butter in a food processor or large bowl if making by hand.
- Either rub the mixture between your finger tips quickly or process on medium speed.
- Do this for about 20 seconds until mixture resembles fine fresh breadcrumbs
- Add egg and process on medium speed for about 15-30 seconds, until egg is incorporated.
- Form dough into a flattened round and place in a freezer bag or wrap in plastic wrap.
- Refrigerate for at least one hour.
- Roll out pastry between two sheets of baking paper or on a lightly floured board to fit a 23cm pie plate.
- Lift pastry into pie plate and gently press into dish.
- Trim pastry overhanging the sides.
- Place a sheet of baking paper on top of the pastry and cover with baking weights.
- Bake at 180 C (160 C fan-forced) for 10 minutes.
- Remove weights and baking paper.
- Bake for 10-15 mins more, until the pastry is a light golden colour.
- Preheat oven to 200°C (180°C fan-forced)
To fill and top - Spoon lemon filling into cooled pastry shell and spread evenly.
- Dollop meringue on top of the lemon filling. Spread meringue to cover filling.
- Form peaks in the meringue with the back of a spoon against the surface of the meringue; lift the spoon to form a peak.
- Bake for about 7-10 mins, or until meringue is lightly coloured.
- Allow pie to cool to room temperature. Cover pie and refrigerate until cold.
- Slice chilled pie into wedges and serve.
- Store pie in an airtight container in the refrigerator.
- Allow pastry shell to cool completely.
Notes
Shortness in pastry terms refers to the tenderness of the dough and is influenced by the fat and sugar content. These ingredients help to minimise the development of gluten, and help break down the gluten found in the flour. This creates ‘short” protein strands. This is achieved when the fat from the butter is rubbed by hand or quickly processed by a blender blade.
When butter meets the glutinous flour, the fat coats two of the starch components: glutenin, which provides strength, and gliadin, which provides elasticity. This creates a barrier between the two elements and prevents them from sticking together. Many shortcrust recipes call for a little ice water, which also prevents the gluten from forming in the dough. If gluten does form, it will make the pastry chewy, rather like pizza dough without yeast. The ultimate goal is for a short crust pastry is to create a crisp crust on the outside with tender softness within.
Once you have your pastry softly rolled into a ball it requires chilling for at least an hour. The purpose of this is to allow the dough to hydrate more fully and evenly.
Sammy’s Luscious Lemon Curd
Note that you need room-temperature curd to spread across the pastry. Therefore you might like to make this in advance. Make a double batch, and you will not regret it!
Ingredients
3 organic eggs, room temperature
1 lemon, juice and zest
2 tablespoons raw organic honey
6 tablespoons coconut oil, melted
Instructions
- In a very clean saucepan, place eggs, lemon zest and juice, honey and coconut oil.
- Whisk together over a low heat until the mixture thickens into a glossy curd.
- Strain through a fine mesh sieve and allow to cool to thicken.
- The curd will continue to set in the fridge.
- Use within 3-5 days.
Notes
Why some recipes use cornstarch to thicken curds and sauces
What we call cornflour in Australia is also known as cornstarch and is often added to conventional lemon curd. The word starch derives from the Germanic word stiff or strong, and this is the effect it has when combines with warm liquid. Think of the great Aussie gravy!
A teaspoon of cornflour goes along way – yet if left lukewarm it will not thicken. Starch consists of thousands of glucose sugar molecules to form a long strand or polymers. When combined, usually whisked or well stirred into liquid over a moderate heat (62-70 C), hydrogen bonds are formed between the starch and water.
This results in the granules of starch swelling and becoming gelatinous, which you will see as the liquid transforms from cloudy to clear, begins to thicken, as it ultimately becomes translucent.
References
This recipe was adapted from here as part of the prescribed text for the food and technology unit for my Le Cordon Bleu masters degree. It has been adapted by me for the purposes of education. The following are more formal references as required for academic submission.
Electronic
Amanda, and Debbie. 2006. Exclusively Food: Lemon Meringue Pie. [ONLINE] Available at: http://www.exclusivelyfood.com.au/2006/06/lemon-meringue-pie-recipe.html. [Accessed 07 December 14].
Darin Sehnert. 2014. cooking stackexchange. [ONLINE] Available at: http://cooking.stackexchange.com/questions/4570/what-does-it-mean-when-dough-is-referred-to-as-short. [Accessed 07 December 14].
McGee, H, 1984. On Food and Cooking. The Science and lore of the kitchen. 2nd ed. New York: Fireside.
Sedgwick, U, 1975. My Learn To Cook Book. 5th ed. Middlesex, England: Hamlyn.
