On Scalding Milk for Still Custards

Chef Laura writes:

I have never really understood the whole scald-the-milk-for-a-still-custard thing. I understand the neccessity for creme anglaise and pastry cream, but I don’t get the importance for baked custards. I scanned previous posts and didn’t see an answer to this. I have nothing in my notes from school. I have made bread pudding without this step and it has been just fine, but in professional kitchens I had to scald the milk, pour it over the eggs, and then strain it. Why?

That’s a question that may have no answer, though you often see it discussed in pastry forums. Why bother with this step? What purpose does it serve? In the case of the bread pudding recipe below, it serves the function of thoroughly infusing the milk with vanilla. But what if I were using vanilla extract? Would I do it? Umm…

My feeling is that scalding milk for still custards like quiches is a holdover from days when chefs used fresh-from-the-dairy (read: unpasteurized) milks. Which is to say it’s very likely a safety thing, not necessary anymore. Yet top chefs from many quarters still insist that scalded milk delivers a more velvety texture in a still custard than milk that’s straight from the bottle. Is that because hot milk helps to uncoil egg proteins? Does it change the milk’s composition in some way? It is simply because a warm mixture cooks more evenly when it’s put into the oven?

Both are at least plausible answers in the absence of an authoritative one. Until that answer comes, milk scalding will continue on as popular kitchen voodoo.

UPDATE: Reader Julie adds:

Why scald milk for baked custards? Hmmm, what about the chalaze? Combining hot milk with the eggs and then straining makes a smoother custard because you strain out the chalazae. I admit to just reaching in with my fingers and pulling them out, but I’m guessing that’s a food service no-no. Also, the baking is often just enough to re-connect the proteins for added firmness from the stirred custard texture, and may not ensure that all the custard makes it to 160F.