Fundamental Rules of Making a Good Pan Sauce
from J. Kenji López-Alt, https://www.seriouseats.com/

Last week, as I drizzled a bit of rich golden brown, glossy, smoothly emulsified and fragrant pan sauce on top of my crisply seared and juicy pan-roasted chicken breast, I thought back to the first time I ever tried to make a pan sauce and the epic failure it produced. It was a white wine and thyme number. Okay, I thought to myself, so I just cook this chicken, then I add stock and wine to the pan, scrape up the browned bits, cook it down, stir in some butter, and I'm done, right?

You can probably guess what happened next. I added a splash of Two Buck Chuck and the canned chicken stock, scraping up the browned bits dutifully as I was instructed to before adding a few thyme sprigs and letting the whole thing reduce, waiting patiently for it to start to thicken up and look glossy like I'd been promised it would in the fancy French cookbooks I was reading at the time. The stock reduced, reduced, and reduced some more until it was down to just a couple of tablespoons. Yet those tablespoons were just as thin and watery as the liquid was when I started. What I ended up with was a half-emulsified, overly salty, greasy sauce with terrible flavor.

It wasn't until I got my first gig cooking in restaurants that it really struck me exactly what a pan sauce is supposed to taste like. These sauces were rich and smooth! They were glossy and brightly flavored and stuck to the meat, leaving a streak of white plate that slowly closed as you swiped each bite through it. They had just the right level of salt and an intensely meaty aroma with not a hint of excess greasiness. These sauces were exquisitely simple and extraordinarily tasty.

So what was it that made the difference? What does a restaurant kitchen have that I was missing back in my college days? Well there's the obvious: In a restaurant, you're starting with flavor-packed homemade stock whereas at home, most folks are using store-bought stock. Reducing good stock gives you concentrated good flavor while reducing bad stock gives you concentrated bad flavor. But even starting with a decent store-bought stock (I use either Swanson organic chicken broth or low-sodium Imagine organic), achieving decent flavor is a possibility, but getting that glossy, rich, non-greasy texture is very difficult. 

It all comes down to two factors: gelatin and heat.

The Science of Emulsions:

Pan Sauce Basics See, a pan sauce is essentially a butter and water emulsion. Sure, there are trace amounts of other things in there that give it flavor, aroma, and brightness, but that rich, mouth-coating texture? The creamy body it gets? That's from the emulsion. As we all know, emulsions are a just-barely-stable mixture of two things that really shouldn't get along under normal circumstances. In this case, water (broth and wine are essentially water), and fat.

A side effect of a stable emulsion is that the whole thing ends up thicker than either constituent on its own, as water molecules have more trouble flowing now that they're hampered by tiny droplets of dispersed fat. The problem is, even with very, very vigorous whisking, it's difficult to actually get those fat molecules small enough to form a stable emulsion. To get there, you need a bit more help, which takes us to the gelatin.

Restaurant stocks are rich with gelatin that are extracted from the bones they're made with. Gelatin is a protein that forms a very loose, flexible matrix inside an aqueous solution, lightly thickening it. It's this thickening that is really key to stronger emulsions. Thickeners will physically impede fat molecules from coalescing, giving pan sauces long-lasting stability.

The other factor a restaurant kitchen has going for it is the intense heat of a restaurant burner. Intense heat means intensely violent bubbling in the skillet. It's those bubbles that end up doing all of the whisking and churning for you.

Recreating a Rich Restaurant Stock

So what's a home cook starting with store-bought stock to do? You have a couple of options, and both of them involve adding just a tiny, tiny bit of thickener to help keep your emulsion stable. The first is my usual go-to technique: just toss your butter cubes in a bit of cornstarch.

Just that tiny amount of cornstarch that clings to the butter's surface is enough to gently thicken your stock as it simmers, giving you a creamy, rich, and glossy sauce at the end.

The second method is one I've been experimenting with recently, and may well become the standard at my house. Since it's gelatin the stock is missing, why not just add some directly? By sprinkling the gelatin over the stock and letting it hydrate while I'm cooking my chicken, it doesn't even add any extra time to a typical recipe!

Step 1: Sprinkle Gelatin First things first: I combine my liquid elements (for instance, stock and wine) in a glass measuring cup and sprinkle on some gelatin to get it started with the hydration process. For two chicken breasts, for instance, mix 1/2 cup dry white wine and 1/2 cup homemade or store-bought low-sodium chicken stock. Sprinkle 1 1/2 teaspoons powdered gelatin on top.

Step 2: Season your meat or fish and sear in a pan. Finish cooking in the oven in the same pan.

Step 3: Transfer your meat or fish to a plate and cover to keep warm

Step 4: Add Aromatics While the chicken rests, it's time to start the pan sauce. First step: Drain off all but a bit of the fat from the chicken, place the pan back on the stovetop, and add your aromatics (such as shallots and garlic), stirring and shaking them until fragrant, just about 30 seconds. (Be careful not to let them burn—you want your stock close by to add it to the pan and halt cooking as soon as those aromatics are fragrant).

Step 5: Add Stock and Wine, and Scrape! As soon as your shallots and garlic hit that sweet spot, hit the whole pan with the stock/wine/gelatin mixture you set aside earlier. While it's true that for pot roasts, braises, and other high-volume projects you should reduce your wine before adding other liquids, for a quick and easy pan sauce like this, you end up reducing the liquid so much anyway that a bit of excess alcohol isn't going to hurt anything. Just go ahead and add it all at once. Scrape up any browned bits with a wooden spoon, incorporating them into the liquid.

Step 6: Reduce Next, reduce that mixture until it starts to thicken (you can tell by the density and size of the bubbles that form—the bubbles will get larger as the sauce reduces. At a restaurant, this takes a minute or so. At home, it'll probably take closer to six or seven.

Step 7: Add Butter Once you hit the medium-to-large bubble mark (your liquid should be reduced to about 1/3 its original volume), add 2 tablespoons butter, assuming the example of two chicken breasts with 1 cup of liquid (wine and chicken broth), and a splash of soy sauce if you want, stirring the butter in with a wooden spoon or a whisk and shaking the pan vigorously as it melts.

Step 8: Add Finishing Herbs Add your herbs (fresh chives, parsley, etc.) and stir them in. If your sauce needs a touch of brightness, now would be a good time to add lemon juice (sauces that start with a bright white wine typically don't need the added lemon juice). When your sauce is ready, it should form clearly visible streaks that slowly close when you drag a spoon through it. If not, keep on reducing!

Once it's hit this consistency, season to taste with salt and pepper. There's a good chance that your sauce might over-reduce while you're slicing your meat. If it does, just reheat it with another splash of stock or water to thin it to the right consistency.