Alton Brown is probably the king of both foodies and food scientists. He understands both worlds and communicates information in a way that is entertaining and easy to understand. I especially love his recipes because they are the basics. If you want to learn how to make anything, I would recommend him first. He tells you the bare minimum of what you need to do to make something delicious while giving you different options to spice it up more if you wish. He also tells you why he does everything he does in the kitchen. It is extremely comforting to any level of cook.
This lemon curd is an Alton Brown recipe. In other words, it’s pretty foolproof. Because Alton Brown is a wizard.
But for real, his recipes are great as are all of his television shows. Especially Good Eats. That’s where most of his food science bits come in. Although occasionally you can find him talking some science in Cutthroat Kitchen or on his podcast.
So in honor of Alton Brown and the soon-to-be-Spring weather, I thought that I’d make his lemon curd and explain exactly what is going on!
First, you whisk the sugar and yolks together before adding the lemon juice. The acid begins to unfold or denature the proteins of the egg yolk. After unfolding, the protein strands begin to reach out and connect with other proteins capturing liquid called coagulation. This slightly thickens the mixture, but the sugar acts as a sort of buffer to prevent them from curdling. That’s why you always you want to make sure that the egg yolks and sugar are well-mixed before adding the juice.
Next you heat the mixture gently over boiling water. This continues to thicken the mixture by denaturing the proteins further. It also acts in conjunction with the lemon juice to kill any unwanted bacteria such as Salmonella. The sugar plays a vital role here as well. Remember how it prevented curdling in the first step? It also prevents the eggs from cooking too quickly and becoming gross scrambled eggs. It keeps the protein strands far enough apart from one another to increase the denaturation temperature window. In other words, it makes it much easier to get the right texture. After gently cooking the curd, it will begin to coat the back of a spoon more thickly than prior to heating.
The final step is slowly adding butter. The cold butter cools the mixture down to prevent it from further cooking. It also adds flavor and adds to the creamy texture of the curd.
There you have it! Voila. Lemon curd.
Adapted from Alton Brown
Makes 1 1/2 cups curd
4 egg yolks
3/4 cup sugar
1 pinch kosher salt
6 tablespoons butter, cut into pats and chilled
1. Add the zest from the lemons into a small bowl. Juice the lemons and measure out 1/4 cup of the juice, then add it to the bowl with the zest (save any leftover juice for another recipe).
2. Fill a small, high-rimmed saucepan with water approximately 3 inches deep. Bring to a simmer over medium heat.
3. Meanwhile, in a heatproof bowl, whisk together the yolks and sugar together until smooth. Add the juice and zest mixture, along with the salt. Continue to whisk the mixture until it’s well combined.
4. Once the water is simmering, place the bowl over the pot of water so that the bottom of the bowl is just above the water’s surface. Whisk continuously until the mixture is thick enough to coat the back of the spoon. This will take about 8 minutes if using a metal bowl, or up to 20 minutes if using a ceramic or glass bowl.
5. Once thickened, take the bowl off of the heat. Add the butter, one pat at a time, whisking until it melts into the mixture.
6. Cover the lemon curd with plastic wrap so that the wrap lightly touches the top of the curd. Refrigerate overnight, or for at least 12 hours.
7. The next morning (if you can wait that long), take the curd out of the fridge and strain it through a mesh sieve, using a spoon to force the curd through the strainer. Discard the remaining zest in the strainer.
8. Store the lemon curd in the fridge in an airtight container for up to 2 weeks. Enjoy on top of baked goods, in a tart, or by the spoonful.
I have also previously made grapefruit curd if you want some more citrus lovin’!