For the Best Potato Salad, Add This to Your Cooking Water

published Jun 10, 2023
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Credit: Joe Lingeman

I used to hate making potato salad. That’s because nine times out of 10, I’d either overcook or undercook the potatoes. Once, when I first started cooking professionally, I staged in a kitchen and they tasked me with making potato salad. Long story short, I undercooked the potatoes and then used them to make a huge amount of “crunchy” potato salad. It didn’t come as a surprise when I wasn’t asked to return.

Years later, during my time at Serious Eats, I made Kenji López-Alt’s classic potato salad on a whim. My potatoes turned out perfectly — and they have every time since — due to one ingenious tip he shares: Adding vinegar to the cooking water prevents overcooking. Coupling this technique with starting the potatoes in cold water and seasoning the drained potatoes while still hot delivers the most flavorful, perfectly cooked potato salad every time. 

What Is the Perfect Potato Consistency?

Kenji is well-known for his in-depth investigations into the science of how food works, and he delivers it in spades with this recipe. Early on, he takes a firm stance on how he feels about undercooked and overcooked potatoes. “If there’s one thing I can’t stand, it’s al dente potatoes. Potatoes should not be crunchy or firm. But nor do you want your potato salad to be cold mashed potatoes,” writes Kenji. 

To remedy this, Kenji borrows a trick he picked up while developing his recipe for the perfect french fry. Simply add a little vinegar to the potato’s cooking water — one tablespoon of vinegar to one quart of cold water, to be exact. 

The Science Behind Why It Works

Potato’s starchy cells are bound by pectin, which acts as the glue that holds them together. As potatoes cook, their pectin starts to break down. Thus, the longer they’re cooked, the more their pectin breaks down, causing potatoes to become mushy. With potato salad, where the desired goal is intact potatoes that are both tender and fluffy, this is the opposite of what you want. 

Because acid significantly slows pectin’s demise, adding some to the cooking water prevents overcooking while simultaneously seasoning the potatoes. You can use this technique whenever you’re cooking diced potatoes that you want to keep intact for the end result (you won’t notice a vinegar taste in the final product). 

Types of Vinegar You Can Use

While Kenji’s potato salad recipe specifically calls for rice wine vinegar because it’s his favorite all-purpose vinegar, I’ve found that white distilled vinegar, white wine vinegar, and apple cider vinegar work well in a pinch. I’d steer away from using dark-hued vinegars like balsamic, sherry, and red wine vinegar, as their stronger flavor will overpower the salad and turn it an unappealing color. As long as you use a type of vinegar you like, you’ll be good to go.