When I think of cream sauces I think of a giant bowl—one of those giant bowl-plate hybrids they have at restaurants—absolutely mounded with linguine and alfredo sauce. And maybe some broccoli. Cream sauces can adorn anything from pastas to meatballs, and while you can simply pour hot cream over them and call it a day, the best sauces are thick. They hug every morsel rather than puddle up on the bottom of the plate. There’s a simple trick to getting your cream sauces extra creamy: add acid.
Extra acid makes cream thicken
Just like how you can add vinegar or lemon juice to milk to thicken it for a buttermilk substitute in baking, mixing in a dose of acid will thicken your cream sauce. Extra acid from the vinegar or lemon juice causes the proteins in the dairy to cling and clump together. It’s the same reason lemon posset sets into a pudding even though it’s only three ingredients. If you add too much, this reaction can potentially look chunky, but just a bit can give it extra body which reads as “creamy” on your palate.
I first stumbled across this idea from Milk Street. The author reduces cream for a pasta sauce to thicken it and then adds lemon juice to give it that extra push. I wanted to see how much acid was needed to thicken the cream without making it chunky, and if vinegar would work just as well. So off to the laboratory (ahem, kitchen) I went and tested out the two with resounding success.
How to make a truly creamy sauce
Warming the dairy speeds up the reaction, and since you probably want warm food anyway, start by adding the cream to a pot or pan. Warm it over medium-low heat until it is steaming and the edges are bubbling. You want to evaporate some of the water and reduce the cream, but don’t bring it to a rolling boil because you could evaporate too much and break the cream.
To make one serving of pasta sauce, I added half a cup of cream to a pot and gently simmered it for about five minutes while stirring. Then I turned off the heat. For the first test I added two teaspoons of vinegar and stirred it in. The cream became noticeably thick and creamy. While it didn’t break, when it cooled the texture bordered on chunky. You can see in the picture the regular cream is thinner where it coated the wall of the bowl, and the vinegar addition allowed the cream to mound up in the center. The spoon shows that the cream sauce is becoming lumpy.
I did the same for adding lemon juice with similar results. Two teaspoons seemed to be too much acid so I reduced it to one teaspoon of acid for a half-cup of cream. This is the sweet spot. The cream sauce was still flowing but became more viscous without bordering on yogurt. Especially if you’re adding cheese, which I eventually did, you just need to add a small dose of acid. Whichever you have on hand will work. Just add a teaspoon of plain old white vinegar or lemon juice to the cream and stir it in.
How to work with the flavor
There is the small issue of acid tasting like acid. While this plays into your hand if you’re making a lemony pasta sauce, what if you’re not? A little acid balances out the heaviness of fat anyway, but you can mask the flavor if you want to. The flavor of straight-up cream with vinegar or lemon juice has a cheesiness to it. This tracks, considering how cheese and yogurt are made with similar ingredients. I suggest leaning into the cheese flavor. Add a couple tablespoons of a strong cheese like parmesan, pecorino, gruyère, or maybe some nutritional yeast to the sauce. Add savory spices like garlic powder, onion powder, or paprika. Sprinkle in some fresh or dry herbs. Your cream sauce can be creamy, but it certainly doesn’t have to be plain.
You can use this thickening trick with any cream-based sauce, just start small. Depending on the other ingredients you have swimming around in there, there could be some acid already. Just add a squeeze of lemon, maybe half a teaspoon at a time and see where that takes you. This recipe for a creamy parmesan pasta sauce makes enough to hug “one serving” of pasta. (Pasta boxes say two ounces of pasta is enough. Pshaw.) Just multiply it if you’re making more than two ounces of pasta.
Creamy Parmesan Sauce Recipe
Ingredients:
½ cup heavy cream
⅛ teaspoon salt
1 teaspoon lemon juice
2 tablespoons shredded parmesan cheese
A hearty crack of black pepper
In a pan or pot, heat the cream and salt over medium-low. Bring it up to a light simmer. The cream should be steaming and bubbling around the very edges. Stir frequently for about five minutes to evaporate some of the water.
Turn off the heat. Stir in the lemon juice. Stir in the parmesan until it’s fully melted. Add a crack of black pepper and your sauce is ready. Toss with pasta, drape over chicken, or dunk chunks of toasted bread into it.