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Apr 29, 2010 09:24 PM

Why won't my key lime pie recipe work with grapefruit juice?

Ok chowhounders, maybe you can figure this out. I make a key lime pie with sweetened condensed milk, 3 eggs and 1/2 cup of lime juice.

This is the recipe:


1 EA 9” graham cracker pie shell
1 EA 14 oz. can sweetened condensed milk
3 EA egg yokes (whites not used)
½ cup key lime juice (I use Nellie & Joes brand)

Preheat oven to 350 degrees F
Combine milk, eggs and lime juice.
Blend until smooth
Pour filling into pie shell and bake for 15 minutes.
Let cool on a baking rack for at least 10 minutes before refrigerating.
Just before serving, top with whipped cream.

I have tried experimenting with different juices. I used persian lime juice and lemon juice and it worked fine. I liked the key lime juice better but the pie worked just as the original did.

I tried strawberry nectar and the pie didn't set. I figured, well, it has to be citrus juice so I tried ruby red grapefruit juice. It didn't set. It stayed liquid. The grapefruit juice is 100% grapefruit juice.... no cocktails or 30% juice or anything like that.

Does anybody have any theories as to why the pie didn't set?

Thank you,

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  1. I don't know for sure but I think it has something to do with the acid content of the citrus juice. Both lemon and lime juice are so strong that if you are going to drink it (lemonade/limeade) you have to add a sweetener and about 3 times as much water as there is juice. When you drink orange or grapefruit juice, water isn't added. I think the extra water made it so it wouldn't set up. There must be baking experts out there that know for sure.

    5 Replies
    1. re: John E.

      Well, I know about baking and I'm thinking the following: it is the low acidity of the grapefruit that's the problem, which is much less than lemons and certainly key limes. All recipes I have for anything lemon/lime warn against using grapefruit juice as a sub, and recommend using orange juice instead, which has a higher acidity than grapefruit. Same problem with the strawberry nectar, I believe, low acidity. Sugar + acidity + egg yolks = coagulation = pie setting up.

      The juice should be added to the egg yolks after the sugar, or in your case, the condensed milk, as there is a coagulation issue with the acidic juice and egg yolks; in other words, mix the egg yolks and sugar first, then add the juice. But I don't think that's the problem, it's just the lower acidity of the grapefruit juice.

      What you could do is make a grapfruit curd and fill the tart shell with it, then top with a meringue, if that's your style, or not.

      Here's a link for a grapefruit meringue pie; the filling is essentially a grapefruit curd:

      So, God bless you for trying but it just won't work.

      1. re: bushwickgirl

        It isn't real huge priority for me to make a pie based on grapefruit juice, I was just experimenting. I'm not even that wild about grapefruit juice.

        I wonder if I added cream of tarter. Wouldn't that make it more acidic?

        I do find it interesting that I got 2 responses in about 30 minutes.

        1. re: tonka11_99

          " interesting that I got 2 responses in about 30 minutes."

          Because it's late and most people, except me, are sleeping on the East coast, anyway. Are you referring to the fact that you got responses at this hour? Maybe it was the subject matter, it caught my eye. I'm a sucker for baking issues.

          I don't think cream of tartar will do it, but try, let us know what happens, or I would go this route: add ascorbic acid; you have tablets of vitamin C kicking around the house, crush up a just a little and raise the acidity of the juice. Works for me.

          1. re: bushwickgirl

            Or sour salt from the kosher foods aisle?

    2. Roxanne D.

      I made a the no bake pie in the new Rachael Ray magazine. No bake grapefruit cheesecake. I had the same problem! It was supposed to set up in two hours. I made it at 11:30 am this morning and it is still runny. Rachael Ray should know this before she puts a recipe in her magazine.