Lemon juice and condensed milk is a classic combination that results in a delicious treat. When you mix the two together, several reactions occur to create the final product. In this article, we’ll explore what exactly happens when lemon juice and condensed milk join forces.
The Science Behind Lemon Juice and Condensed Milk
First, let’s look at the ingredients we’re working with. Lemon juice is an acidic liquid that contains about 5% citric acid, which gives it a sour taste. The acidity level of lemon juice usually falls between 2 and 3 on the pH scale. Condensed milk is milk that has been heated to remove about 60% of its water content. It contains milk proteins like casein and whey, milk sugars like lactose, and milk fat. The process of removing water makes condensed milk much thicker and creamier than regular milk.
When acidic lemon juice hits condensed milk, several chemical reactions occur:
- The citric acid in the lemon juice lowers the pH of the condensed milk, making it more acidic.
- The acidic environment causes the milk proteins (casein and whey) to denature or unravel from their normal structure.
- The denatured proteins then cluster together, forming clumps of solid curds.
- The milk sugars and fats remain dissolved in the liquid whey.
- You’re left with solid curds swimming in creamy whey.
The high fat content of condensed milk also plays a role. Milk fats like butterfat solidify when they come into contact with acidic lemon juice, contributing to the clumps of curds that form.
Step-by-Step Instructions
Making lemon curd with condensed milk is an easy kitchen science experiment. Here are step-by-step instructions for how to turn two liquid ingredients into a lush, lemony treat:
- Gather your ingredients – one 14 ounce can of sweetened condensed milk and 1/3 cup freshly squeezed lemon juice (about 3 large lemons’ worth).
- Open the can of condensed milk and pour it into a mixing bowl or liquid measuring cup. Make sure you have at least 1 1/4 cups room in the container as the curd will expand slightly when mixed.
- Add the fresh lemon juice and whisk vigorously for about 2 minutes, until thoroughly combined.
- Let the mixture rest for 5-10 minutes. It will thicken up quickly as the proteins coagulate and the fats solidify.
- Whisk the curd again for another 2 minutes – it should now have a thick, pudding-like texture.
- If you want a smoother curd, you can blend it in a food processor or blender for 1 minute before transferring it to a storage container.
- Transfer the lemon curd to an airtight container and refrigerate for at least 1 hour before using. The fridge allows it to cool completely and firm up.
- Store leftover curd in the refrigerator for up to 1 week. The acidic lemon will help preserve it.
And that’s it – you just turned condensed milk into a bright, velvety lemon curd in a matter of minutes!
Variations and Uses
This basic lemon condensed milk recipe is very versatile. Here are some ideas for variations and how to use your homemade lemon curd:
- Add different citrus juices – Substitute lime, orange, or grapefruit juice for new flavors.
- Sweeten or tang it up – Adjust the sweetness by adding more or less lemon juice to taste.
- Smooth or chunky – Blend for smooth curd or leave a little lumpy for texture.
- Thicken it up – For pie filling, add 2-3 tablespoons cornstarch when whisking.
- Mix in berries – Fold in blueberries, raspberries, or strawberries once cooled.
- Layer it – Spread curd between cake layers, graham crackers, biscuits, or scones.
- Fill and top desserts – Use as a filling for tarts, cream puffs, donuts, or whoopie pies.
- Eat with a spoon – Top with whipped cream for an easy dessert.
Lemon curd made with condensed milk has a velvety richness that you don’t get from curd made with eggs and butter. It’s delicious in both sweet and savory applications.
Frequently Asked Questions
Is condensed milk curd cooked or uncooked?
Lemon condensed milk curd is uncooked. The mixture thickens thanks to the chemical reactions between the acidic lemon juice and milk proteins, not because it is heated. The curd is safe to eat without cooking.
Can I use fresh lemons instead of bottled juice?
Absolutely! Freshly squeezed lemon juice makes the best curd. You’ll need about 1/3 cup or juice from 3 large lemons. Make sure to strain out any seeds.
How long does lemon condensed milk curd last?
Properly stored in an airtight container in the fridge, lemon curd made with condensed milk will last for 1 week. The high acidity from the lemon juice helps preserve it.
Why does my curd come out runny?
If your curd doesn’t thicken up, there are a few possible reasons:
- Not enough lemon juice – Use at least 1/3 cup of juice per can of milk.
- Bottled lemon juice was old – Always use fresh squeezed juice.
- Didn’t let it rest – Give the curd time to thicken after mixing, about 10 minutes.
- Didn’t chill it – Refrigeration helps firm the curd up.
Can I make lemon pie with condensed milk curd?
You sure can! Just thicken the curd more with 2-3 tbsp of cornstarch and use it as the filling in your favorite pie crust. Chill the pie completely before slicing.
Nutrition Information
One serving (2 tablespoons) of homemade lemon curd made with condensed milk has approximately:
| Calories | Fat | Carbs | Protein |
|---|---|---|---|
| 110 | 5g | 16g | 2g |
As you can see, the majority of calories come from carbohydrates (mainly sugar) rather than fat, since there is no butter. Lemon curd made this way has a lusher, creamier mouthfeel than classic curd despite having less fat.
Conclusion
Whipping up lemon curd with condensed milk instead of eggs and butter is an easy way to get lush results. The chemical reactions between the acidic lemon juice and milk proteins give you a velvety dessert topping or filling without any cooking required. In just a few minutes, you can transform pantry staples into something special.
Experiment with different citrus juices or mix-ins to customize the flavor. Dollop it over cakes, stuff it into cookies, or eat it with a spoon. However you use it, homemade lemon condensed milk curd is sure to be a new favorite.