Achieving the proper consistency for both potatoes and sauce is not easy. Also, if you overcook the potatoes, they disintegrate when added to the dressing.
The best Austrian potato salad has a luxuriously thick, velvety dressing and potatoes that practically melt in your mouth.
We chose to use Yukon Golds because they had just enough starch to contribute creaminess to the salad without breaking up too readily. Many recipes call for cooking the potatoes in their skins to improve flavor, but we found this made very little difference. We peeled and cut them into pieces so they would cook evenly, then focused on how to cook them to the perfect degree of tenderness every time.
In a potato, individual cells are filled with starch and held together with pectin. As a potato cooks, the pectin weakens and cells begin to burst, releasing starch. We needed a way to release enough starch to thicken the sauce yet prevent the pectin from weakening so much that the potatoes fall apart. Pectin breakdown is inhibited in acidic environments, so adding vinegar to the cooking water allowed the potatoes to stay firm for several minutes after they softened. It also penetrated the potatoes as they cooked, heightening the tanginess of the finished dish.
This gave us an idea-rather than submerging the potatoes in a large pot of water, we simmered them in a shallow pan with chicken stock, water, vinegar, sugar, and salt. This made the potatoes’ doneness easier to monitor. We then reduced the cooking liquid and reserved some to use for the dressing. This allowed the potatoes to absorb the flavor of the simmering liquid, yielding a deeply flavored salad.
There was one more hurdle to clear before we achieved an ideal potato salad. Too much stirring allows an excess of starch to enter the mix, turning the potatoes gluey. To ensure that the same amount of starch was released from the spuds each time, we honed in on just a few of them. After our potatoes were cooked, we removed several and mashed them into the reserved cooking liquid until the mixture turned thick and creamy, then gently folded in the remaining potatoes. Bingo! This allowed us to create a sauce that was virtually identical from batch to batch.
For flavorings, we substituted sharp, salty cornichons for sauergurken, the hard-to-find lightly pickled cucumbers used in most Austrian potato salads. Red onion gave the salad mild sweetness and crunch, Dijon mustard added pungency, and chopped chives finished the dish.