A quick note on adding wine to a cream sauce

A few years ago I learned the hard way that you should add wine to a cream sauce at the end, not the beginning.

I was making macaroni and cheese. For extra flavoring I like to add a splash of white wine to the cheese sauce. Normally I did this at the end. However, this particular time I decided to add the wine at the beginning instead. I don't remember why. I had made the roux, and before it thickened I added the wine. Well, the sauce never thickened. I kept stirring and stirring and stirring and the flour never did its magic and thickened the sauce. I couldn't figure out what was going on.

Finally, I decided to throw in the cheese, thinking maybe that would thicken the sauce. Well, the cheese melted, but it stuck together like a gloppy clump in the sauce. It never blended with the rest of the sauce.

It turns out that wine is an anti-thickening agent. And, in a cream sauce, it can actually cause the cream/milk to curdle, keeping the constituent parts of the sauce separate. This is why the sauce never thickened, and why the cheese never blended in to the sauce.

The way to add wine to a cream sauce is to make the sauce as usual, but cook it to a point where it is a little too thick. Then, add the wine. The wine will thin the sauce back to the thickness it should be at, and then you're done.