The lemon meringue pie experiments are coming along well, and I’ve learned a few tricks along the way. There are details most recipes don’t mention and that I wouldn’t have known had it not been for a reader named Cheryl who sent me this article with lemon meringue pie making tips from Johnson and Wales.
Skipping everything about the crust (because that's a whole different subject) some of the key things I’ve learned are as follows:
1. Add the lemon juice last because the acid keeps the filling from thickening properly and adding acid too early helps "cook" the egg yolks which should not be over-cooked. Over-cooked eggs are what caused the first pie filling I made to separate. Adding the lemon juice too early didn’t help either.
2. It’s best not to use a double-boiler because the mixture doesn’t get enough heat to form a gel (so says the article, though a lot of recipes call for a double boiler). I’m eliminating recipes that call for double boilers since they’re kind of a pain anyway. That being said, Cheryl’s used a double-boiler for 40 years and her pies are great.
3. Always put the meringue on the filling while it’s piping hot. The hot filling helps cook the meringue from the bottom up and helps keep it from weeping.
Finally, meringue can be made ahead of time so long as you have the filling ingredients ready to go. I tried a few different meringues, including one that was very low in sugar and another that had a lot of crazy steps including making a gel, grinding up sugar and cornstarch before adding. The best meringue was the one used on the Betty Crocker Pie -- 3 eggs, ¼ tsp. cream of tartar, 6 tablespoons sugar and a little vanilla. Simple and good.
Now the challenge is to find the best filling. Above is a chart showing yolk/juice/water/thickener amounts. Betty Crocker’s is first, with the most sugar and Cheryl’s recipe uses the least. I’m making Cheryl’s again today just to test it again, but I had great success with the Betty Crocker recipe. It had a lot of sugar, but there was enough lemon and butter to balance it out so it wasn’t terribly sweet. I did add ¼ teaspoon of salt.
Here's a link to a tried and true lemon meringue pie.