Vanilla custard for ice cream

[Darienne]

Looked this one up but couldn't find anything.

My custard separated and I thought it might be because I had used previously frozen whipping cream...sorry it is true.

So I wandered around Google trying to find an answer and came up with this: "Sometimes, in spite of every precaution, the custard separates."

Fascinating. No possible precautions are listed and I am left wondering how to rectify my error.

BTW, the ice cream was fantastic anyway.

Edited February 22, 2009 by Darienne (log)

[alanamoana]

I just read your original post about this in the chocolate ice cream thread...you gave the bit of information that you are missing in this query: you were cooking your custard and it separated. The separation didn't happen after the custard had set up, correct?

If this is the case, you (very likely) overcooked your custard and made scrambled eggs. So, while blending the mixture smoothed it out, it likely would not have had the same mouthfeel as custard which had been cooked to the proper consistency would have had. Egg proteins are pretty sensitive and when they are overcooked, they tighten up and squeeze liquid out, therefore looking separated. When a creme anglaise (or custard base) is cooked to the proper consistency, the egg proteins have expanded and have trapped liquid in their matrix, thus thickening the liquid. With ice cream bases, you can let them sit in the fridge overnight and you'll probably notice that it will be a little thicker after the aging. That's because the egg proteins continue to expand or absorb liquid for a little longer. That's one good reason to make an ice cream base ahead of when you need to freeze it. When making an anglaise it is also a good idea to have an ice bath as part of your mise en place, so you can cool your mixture down immediately after taking it off the heat. There's a fine line between done and overdone when working with custards. I usually strain through a chinois (very fine mesh strainer) directly into a clean container set into my ice bath) and stir frequently during the cooling process both to prevent a skin from forming (may happen with rich bases) and to help redistribute the heat during cooling. I never remember the actual temp, I go by feel and look, but it is somewhere around 170F. The sugar in the mixture allows the temp to go a little higher than you could with plain eggs.

[Darienne]

I just read your original post about this in the chocolate ice cream thread...you gave the bit of information that you are missing in this query:  you were cooking your custard and it separated.  The separation didn't happen after the custard had set up, correct?

If this is the case, you (very likely) overcooked your custard and made scrambled eggs.  So, while blending the mixture smoothed it out, it likely would not have had the same mouthfeel as custard which had been cooked to the proper consistency would have had.  Egg proteins are pretty sensitive and when they are overcooked, they tighten up and squeeze liquid out, therefore looking separated.  When a creme anglaise (or custard base) is cooked to the proper consistency, the egg proteins have expanded and have trapped liquid in their matrix, thus thickening the liquid.  With ice cream bases, you can let them sit in the fridge overnight and you'll probably notice that it will be a little thicker after the aging.  That's because the egg proteins continue to expand or absorb liquid for a little longer.  That's one good reason to make an ice cream base ahead of when you need to freeze it.  When making an anglaise it is also a good idea to have an ice bath as part of your mise en place, so you can cool your mixture down immediately after taking it off the heat.  There's a fine line between done and overdone when working with custards.  I usually strain through a chinois (very fine mesh strainer) directly into a clean container set into my ice bath) and stir frequently during the cooling process both to prevent a skin from forming (may happen with rich bases) and to help redistribute the heat during cooling.  I never remember the actual temp, I go by feel and look, but it is somewhere around 170F.  The sugar in the mixture allows the temp to go a little higher than you could with plain eggs.

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Hi Alanamoana,

Thanks very much for your explanation. I do realize that I overcooked the custard. Now. Had no idea.

Almost everything I make, I make for the first time. An incredible level of novice. Funny, it is in one sense, one 'failure' after another as I learn how to make things. But then with the help of the good folks on this list, and an evergrowing selection of books, I am learning how to do it all. It's never too late.

Thanks again.

[abooja]

I bring my custard mixtures to around 182F before straining them into a bowl set above an ice bath. A portion of the cream is set aside and kept cold so that the mixture cools that much faster once the custard is added. The only times I have had any clumping whatsoever was when I brought it up to even slightly higher than 182 and/or waited too long to add the custard to the ice bath. This is more likely to happen with smaller batches. I'd invest in a Thermapen (or a knockoff) to guarantee consistent results.

[Darienne]

I bring my custard mixtures to around 182F before straining them into a bowl set above an ice bath.  A portion of the cream is set aside and kept cold so that the mixture cools that much faster once the custard is added.  The only times I have had any clumping whatsoever was when I brought it up to even slightly higher than 182 and/or waited too long to add the custard to the ice bath.  This is more likely to happen with smaller batches.  I'd invest in a Thermapen (or a knockoff) to guarantee consistent results.

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Thanks. Learn, learn, learn....

[paulraphael]

I see a lot of recommendations for temperatures for custard mixtures ... the trouble is it will vary enormously depending on the concentration of egg yolks. A custard with 12 yolks per quart might curdle at 150°; one with two might not curdle until closer to 190°.

Other ingredients also have an effect. If you have some starch in the mixture, it will practically eliminate the possibility of curdling. At least in theory, a bit of flour or cornstarch (the latter actually being a useful ice cream ingredient) would let you bring the custard to a rolling boil. Which there's no reason to do, but, at least you'll know you have some slop insurance.

Overall the best bet is to get comfortable making custard / creme anglaise the old fashioned way. Have an even-heating, responsive saucepan and a flat-bottomed spatula, stir constantly over medium heat, and pay close attention to the consistency. When the mixture thickens, stir for a few more seconds, remove from the heat, and then stir some more. When you get the hang of this, you'll never have another problem. unless you get into making huge batches, which can be tricky.

[abooja]

Good point. My vanilla ice cream mixture is 2 cups of heavy cream, 1 cup of whole milk, 5 large egg yolks, 150 grams of granulated sugar, one vanilla bean, 3/4 teaspoon of vanilla extract and a pinch of salt. It's essentially the David Lebovitz recipe, minus one egg yolk.

Edited February 23, 2009 by abooja (log)

[pnwradar]

I also follow DL's recipe, but with 2c milk & 1c cream, and one less yolk -- we apparently like our dessert a little less rich than he does, where it's not coating the spoon with butterfat.

After a lot of experimenting, I've settled on taking the custard to 160F (IR non-contact thermometer), strain, then rapidly cooling (soup chiller) before mixing into the chilled cream + flavoring. Might want to cook to a higher temp for serving to the infant and infirm, or use pasteurized egg whites.

-jon-

[Darienne]

Wow! So much excellent and useful information in this topic now.

And we all do like our ice cream (and chocolate) different. I found the Cuisinart premium Vanilla Bean recipe way too rich for my taste. And now I have made a Coconut Ice cream for my friend, which I found way too sweet and way too much coconut. Interesting. She and my DH both loved it.

What I am really going towards is making frozen yoghurt which I prefer to ice cream anyway, and to date that's speaking only of the commercial stuff, both ice cream and yoghurt.

The little Cuisinart booklet has some yoghurt recipes and I'll try them next. Has anyone any do's and don't' s specifically for frozen yoghurt that I should know about ahead of time?

Thanks.