How do I get my roast potatoes crispy?
Add about 1/2 teaspoon of baking soda per 2 quarts of water when you parboil the potatoes. The mildly alkaline water breaks down their surface. Drain, shake them in the pot to rough up the edges, then roast at about 425°F: the starchy paste turns into a thick, craggy crust. More soda can taste soapy.
How to do it
- Cut the potatoes into large chunksPeel them if you like and cut them into roughly 2-inch pieces. Starchy varieties such as russet or Yukon Gold give the fluffiest edges.
- Add baking soda to the boiling waterUse about 1/2 teaspoon of baking soda per 2 quarts of salted water. Keep it to that pinch, because more can leave a soapy taste.
- Parboil until just tenderSimmer for about 8 to 10 minutes, until a knife slides in easily but the pieces still hold their shape.
- Drain and shake to rough up the edgesDrain well and let the potatoes steam dry for a minute. Then return them to the pot, cover it and shake until the surfaces look fuzzy and pasty.
- Roast in hot fat until deep brownToss them with oil or fat and roast at about 425°F for 40 to 50 minutes, turning once, until they are craggy and deep brown.
Questions that come up
Will the potatoes taste like baking soda?
At about 1/2 teaspoon per 2 quarts, most people can't taste it, because nearly all the water gets drained away. The taste appears when you use much more: the potatoes turn slightly soapy or bitter and can go mushy. Measure it rather than eyeballing it.
Can I use baking powder instead?
Not really. Baking powder contains an acid that cancels out much of its alkalinity, so it breaks down the surface far less. It may help a little, but baking soda does the work here. If you leave it out entirely, you still get good roast potatoes, just smoother and less craggy ones.
Does this work in an air fryer?
Yes. The parboil and shake steps work the same way, and the roughed-up surface crisps well in an air fryer. Toss the pieces in a little oil, cook them in a single layer and expect a shorter cook, often around 20 to 25 minutes at 400°F, shaking the basket halfway.
Why did my potatoes fall apart in the pot?
Most likely they boiled too long, or the soda amount crept up. Alkaline water softens potatoes faster than plain water, so check a few minutes earlier than usual and stop as soon as a knife slides in. Waxy varieties such as red potatoes hold together better but give a less fluffy crust.
Full transcript
Crispier roast potatoes? Add baking soda to the boil. Half a teaspoon per two quarts of water, then parboil until just tender. Drain, then shake them in the pot to rough up the edges. That starchy fuzz roasts into a craggy crust. Listen.