Creme brulee: pasteurized yolk vs. fresh yolk

[Andreas]

The last few days I tried to get a recipe right for a chestnut creme brulee. Since I needed a bigger amount (about 20 ramekins) I bought pasteurized yolks since I did not want to have 20 egg whites in my home fridge. I forgot to measure the weight of the yolks during my experiments (measured everything else by weight, just not those...) so I looked it up in various sources.

According to "On food and cooking" a US large yolk should have ~17g, according to Wikipedia an EU Large yolk is ~19g. I normally use medium yolks so I figured I couldn't be that wrong using 19g. I substituted the yolks in my recipe 1:1 for pasteurized yolks.

I calculated my egg weight, made my creme, waited for it setting...but it did/does not really set. It's more like a light custard. On my other tries I normally got a nice creme that would pretty much hold it's form.

Here the ingredients for reference:

• 150g cream
  
• 13g vanilla sugar
  
• 30g sugar
  
• 75g chestnut puree
  
• 2 yolks
  

Method:

Heat cream, sugar and chestnut puree until near boiling, strain through sieve.

Mix yolks with vanilla sugar, temper the eggs and mix with the cream.

Fill into ramekin, bake in waterbath @ 110°C for ~40 minutes.

With the fresh yolks this yielded a really nice texture, the ones I have now are more like a thick soup... I checked my "calculations" for scaling the recipe up those seem to be right.

Do pasteurized yolks set differently than fresh ones? How to convert between fresh and pasteurized yolks?

Edited December 1, 2012 by Andreas (log)

[JeanneCake]

I've seen similar results when using pasteurized yolks when making fruit curd - compared to using shell eggs, the 'set" in the curd is much softer with the carton stuff. I don't know why that is; i wonder if some of the proteins are neutralized during processing. I know this isn't much help, sorry

[Andreas]

It is some help, since that tells me that the problem could really be the eggs, not just me doing something wrong...

Your theory could be right btw.: After looking it up I now know that pasteurized eggs are heated to ~72°C, whereas they start to coagulate at ~60°C. Modernist Cuisine suggests that this temperature only needs to be applied for ~10 seconds, but during the heating and cooling process parts of the yolk could already have set.

After you had those problems, have you tried to find out how much pasteurized yolk to use instead of one fresh yolk?

[JeanneCake]

When making key lime pie, I always use the pasteurized yolks, and I use .62 oz of the carton stuff to replace 3 large fresh yolks, so if you were to use about 15-17 grams or .2 oz per large yolk that would probably be ok. I use the pasteurized yolks for this recipe only because there's so little cooking involved - the acidity of the lime juice is what is setting the mix not necessarily the heat.