Week 5: Lemon Curd

Last week, I found my reference recipe, and now I can begin tuning it. In Week 3, I learned that a higher yolk to whole egg ratio makes a thicker, richer texture and mutes some of the lemon's tartness, while a lower ratio makes a lighter texture and brighter flavor. My reference, Split I, has a 4:1 yolk to whole egg ratio (by number) and it is a little bit heavy for my taste, so I am going to try some smaller ratios and see what works best. I also found that there wasn't quite enough flavor with 2 lemons worth of zest (~5 g), so I am going to double the zest and keep the salt at 1/2 tsp to make my modified reference, Split L. I want to keep the batch sizes the same to limit variability, so I am going to keep the total sum of the yolk and whole egg the same for this test and just calculate how much yolk and whole egg I need to hit the ratios of 3:1, 2:1, and 1:1. This means I'll be using partial eggs for this test, but I will scale the final recipe to an integer numbers of eggs and yolks.

Table 1: Splits of reference recipe with different yolk to egg ratios.

Splits L, M, N, and O have yolk to egg ratios of 4:1, 3:1, 2:1, and 1:1, respectively. Split O was light and bright, but it had no richness, so a 1:1 ratio is too low. Split N started to get some richness, but was still mostly light and bright. Split M had the rich, velvety mouthfeel I was aiming for. It was rich at the beginning, but had a bit of lift on the backend that lightened it up. Split L had the same richness as Split M, but it was thicker on the backend, which made the mouthfeel constant throughout.

From the top left corner going clockwise: Split L, Split M, Split O, Split N.

I agonized over how to pick between Splits L and M, and it really came down to a personal preference. I really liked having both the richness and a little bit of brightness at the end (plus, as my friend noted, the brightness means that you can eat more lemon curd!). I will thus take Split M for my reference going forward. Next week, I will play with the butter to egg ratio to try to find the right balance of richness and flavor.