Why It Works
- Storing potatoes in the refrigerator allows enzymes to convert starches to sugars, giving the potatoes a hint of sweetness and a creamier texture.
- Peeling and slicing the potatoes before cooking helps them cook more evenly, while boiling them along with their skins adds back some of the skins' earthy flavor.
- Adding vinegar to the potatoes immediately after cooking allows the vinegar to penetrate more deeply.
- Chicken broth adds savory depth to the dressing.
Imagine if someone described their favorite movie to you like this: There's, like, this nerdy farm kid who enjoys shooting animals on the weekend, and he unwittingly gets involved in some major political conflicts that he barely understands, makes out with his sister, and then uses a combination of magic and a poorly designed HVAC system to commit genocide against thousands of construction workers, technicians, and support staff, most of whom probably have families. (Oh, and spoiler alert, Darth Vader is really his father.)
And now, imagine that it's your job to go make that movie. You may well end up with a great movie of your own, but chances are, it's not gonna be too much like the original Star Wars.
That's what it's like when you're tasked with coming up with a recipe for a dish you've never tasted, from a country you've visited only once, when you were a young teenager.
We're all familiar with American and German potato salads, but less so with their Austrian counterpart, a lighter, brighter version of the dish that's simultaneously more refreshing (there's no mayonnaise in it, and relatively little fat overall) and deeper in flavor, thanks to the incorporation of chicken broth and the savoriness it brings. It's flavored with onions, vinegar, and mustard (sometimes with a bit of chopped gherkin) and bound together in a light sauce that gains its creaminess solely from the natural starch found in the potatoes.
The Austrian-style potato salad recipe I developed for Cook's Illustrated in 2008 (paywall) was certainly delicious, I can tell you that, and I'd done enough research on how Austrians make their erdäpfelsalat* to know that I'd gotten the basics right—sliced yellow potatoes, onions, and a splash of chicken broth—but it was still an interpretation based on hearsay.
*I love the literal translation of this word: "earth-apple salad."
That was then, and this is now. After returning from a long trip around Europe that included dragging my wife and infant daughter all across Austria, eating all the schnitzel, wurst, and erdäpfelsalat I could find, I had the idea that I'd use this "research" to help develop recipes for Wursthall, a restaurant in San Mateo. Really nailing the potato salad was one of the first things on my agenda.
The first hurdle I had to tackle was the potatoes. There are three major commercial varieties: starchy russets; waxy, creamy reds; and Yukon Golds, which bridge the gap in between. The potatoes I tasted in Austria were unvaryingly of the yellow variety, but they tasted fundamentally different from the ones I get back home. While ours tend to have an earthy starchiness to them, the potatoes in Austria were sweeter and creamier.
I tried adding just a touch of sugar to the water in which I boiled them, in the hopes of adding some sweetness, but the flavor ended up cloying and one-dimensional compared to the more complex natural sugars found in the Austrian potatoes.
Many recipes call for cooking mid-sized potatoes in boiling water until they're completely tender; this leaves their skins easy to rub off under cool running water. I compared this method side by side with potatoes that I peeled before cooking, as well as potatoes that I peeled and sliced before cooking. There was no question that cooking them with the skins on produced potatoes with more flavor than cooking them peeled. But cooking potatoes whole produced a different problem:
Even when I started them in cold water, it was hard to get them to cook evenly. By the time the very centers were tender, the exteriors were overly soft, disintegrating into the salad. A bit of soft potato thickens up the dressing and gives the salad creaminess, but too much turns it into cold, chunky mashed potatoes.
So how to get the nice, evenly cooked texture of sliced potatoes, but the flavor of potatoes cooked with their skins on? Easy. Just add those skins to the cooking water as the potatoes simmer.
I placed my sliced potatoes in a pot, covered them with salted water—it's essential to salt the water when boiling potatoes if you want them to come out flavorful—placed a fine-mesh strainer on top, and set the potato skins in the strainer, with the idea that their flavor would infuse the water like a tea.
It worked out great. You wind up with perfectly cooked potato slices that have all the flavor of potatoes boiled whole.
As I found out when working on the classic American potato salad recipe for my first book, the other key for building great flavor into the potatoes is to sprinkle them with vinegar (I used white wine vinegar) while they're still hot.
The easiest way to do this is to drain them, then spread them out on a rimmed baking sheet. As hot potatoes sit, they continue to release trapped moisture in the form of steam. As that water escapes, it leaves behind gaps in the potato's structure that get filled with whatever happens to be around. In things like French fries or hash, for instance, oil will move into those spaces. In this case, the vinegar ends up getting absorbed. This only happens if you add the vinegar while the potatoes are still busy losing moisture through steam.
For the dressing, I went with a pretty classic mix: a dollop of mustard for sharpness, a touch of sugar, some olive oil, some minced red onion (you can also use Vidalias or other sweet onions), a sprinkling of chives (parsley would also be tasty), some more vinegar, and some chicken broth. (In this case, store-bought low-sodium broth works just fine.)
I folded everything together, working some of the starch from the potatoes into the dressing. The salad should be far looser than a typical American potato salad. Think of it more like sliced potatoes in a vinaigrette, as opposed to a scoopable mixture. As I quickly learned, it thickens up a little as it sits and more starch gets absorbed into the dressing, so when you first construct it, it should seem almost soupy.
But hang on a minute. I still hadn't addressed the issue of the sweetness in those Austrian potatoes. Sometimes finding the solution to problems like this requires hard work and critical thinking. In this case, all it required was a bit of laziness and some post facto research. While testing, I'd bought a big ol' 25-pound bag of potatoes to work with, many pounds of which ended up accidentally left in the bottom drawer of my fridge for several weeks before I finally rediscovered them.
Imagine my surprise when, after boiling them, I found that they were noticeably sweeter and creamier in texture than the exact same potatoes pre-storage!
It shouldn't have surprised me too much. Some years back, when I was doing research for my French fry recipe, I'd learned that one of the banes of the French fry industry is an effect known as cold-induced sweetening (CIS). This is the accumulation of reducing sugars in potatoes as they sit at fridge temperatures, and it's caused by enzymatic breakdown of starch molecules. It's a bad thing in French fries or roast potatoes, which can come out unpalatably dark, but in the case of this potato salad, it was exactly what I needed to give those potatoes the right level of natural sweetness.
What I'm saying is that if you want the ideal Austrian-style potato salad, you're gonna have to do a bit of advance planning and let your potatoes just sit in the fridge for a couple weeks before cooking them.
2 pounds (1kg) Yukon Gold potatoes, peeled, quartered, and cut into 1/2-inch-thick slices, peels reserved separately (see note)
3 tablespoons (45ml) white wine vinegar, divided, plus more to taste
1/4 cup (60ml) extra-virgin olive oil
1 tablespoon (15ml) Dijon mustard
3/4 cup (90g) minced red onion, from about 1 small onion
2 tablespoons (6g) minced fresh chives
1/2 cup (120ml) homemade or store-bought low-sodium chicken stock
2 teaspoons (about 10g) sugar
Freshly ground white or black pepper
Place sliced potatoes in a large saucier or Dutch oven and cover with water. Season generously with salt. Place potato skins in a fine-mesh strainer and place on top of pot. Add just enough water to submerge potato skins. Bring to a boil over high heat and simmer until potatoes are tender, about 15 minutes.
Discard potato skins, drain potatoes, and transfer to a rimmed baking sheet. Immediately sprinkle with 2 tablespoons (30ml) vinegar and set aside to cool. When they are cool enough to handle, transfer potatoes to a large bowl.
Add remaining vinegar, olive oil, mustard, red onion, chives, chicken stock, and sugar. Using a rubber spatula or wooden spoon, roughly stir and fold mixture so that potatoes release some starch and liquid begins to thicken a little. Season to taste with more salt and white or black pepper. Set aside to rest for at least 30 minutes and up to overnight. (If resting longer than 4 hours, cover bowl and transfer to refrigerator.) Stir again vigorously to thicken dressing; it should have a loose but not soupy consistency. If it's too thick, thin it out with a little extra water or chicken stock and re-season. Serve cold or at room temperature.
- For the best flavor, store your potatoes in a bag in the refrigerator for 2 to 3 weeks before using them in this recipe, in order to allow natural sugars to build up.