Mastering the mysteries of potato salad

For our Christmas Day buffet, I made potato salad. It was a great success, and I was looking forward to eating the leftovers on Boxing Day - but it was so cold and wet I didn't feel like it, and bought a supermarket pouch of soup instead (because I can't be bothered making any). Still, I learnt a lot of interesting things in pursuit of potato salad mastery, so I thought I'd share the essentials with you, plus a recipe,  because today the sun is out and it feels like salad weather again.

1. Good potato salad requires potatoes that are neither under-cooked nor over-cooked. Starting the potatoes in boiling water is a bad idea, because the outside overcooks before the inside is even warm. So always start the potatoes in cold water.
2. Adding 1 tablespoon of rice or white vinegar per litre of cooking water, as well as salt, both seasons the potatoes and helps to prevent over-cooking.
3. Because potato salad is eaten cold, it needs more seasoning than potatoes served hot. Adding more some seasoning to the hot drained potatoes is much more effective than waiting until they're cold.
4. Mayonnaise needs to be added later when the potatoes are cold, and you can add a bit more vinegar at this stage too, along with pepper.

If you really want to know every detail of the science behind all this, complete with the cellular construction of potatoes and pictures using green dye to show how seasoning gets in, go here.
The Food Lab guy's final word:

Two tablespoons of vinegar in the cooking water, another to dress the hot potatoes, and a final two in the mayonnaise mixture add plenty of layered brightness. Mayonnaise—be it storebought or homemade—is a must... By stirring the salad vigorously, you can bash off the corners of the potatoes, which get mashed up and extend the amount of creamy dressing to tender potato chunks. For heat I add a few tablespoons of whole grain mustard.

Okay, so here's my NZ adaptation of the 'Classic Potato Salad' recipe provided by Serious Eats to go with the lab report:

1.5 kg smallish boiling potatoes
2 litres cold water
2 Tbsps salt
2 Tbsps sugar
2 Tbsps rice or white vinegar

Add potatoes, salt, sugar and vinegar to water in a large saucepan. Bring to boil, reduce to a slow boil and cook until done (test for doneness after about 10 minutes' slow boiling - mine took about 20 minutes to cook through). Drain, peel and cut into chunks (not too small or they'll go mushy).

2 Tbsps vinegar

Transfer warm cut up potatoes to rimmed baking sheet. Spread into an even layer, then sprinkle with vinegar. Allow to cool to room temperature, about 30 minutes.

·                          

·      Add extras according to preference - the quantities depend on how many potatoes you're using, but the potatoes should prevail:
      
      Original recipe
      Finely diced celery

·           Finely diced red onion

·           Finely sliced green parts of spring onions
      1/4 cup chopped cornichons (tiny gherkins)
      Finely chopped Italian parsley
     
      Some NZ extras or alternatives:
      Hard-boiled eggs, chopped
      Corn kernels (cut from a cob microwaved for 3 minutes)
      Finely diced shallots (milder than the red onion)
      Capers instead of cornichons
      Finely chopped fresh chives

Mix gently into cut up potatoes, then add:
      Bought or home-made mayonnaise 
      (Not too much, it shouldn't be overwhelming. For super-easy home-made mayonnaise, go here. I made it with the finely chopped garlic, but leave that out if you don't like it.)

Taste and mix in gently, according to preference:
      Grainy mustard
      A little more vinegar or a little lemon juice

Chill for a few hours or overnight - take out of fridge an hour before serving.

Those who know my blog well will recognise that once again, I took the photo only after we'd eaten most of the potato salad!