The appeal of potatoes has seemingly eroded over the last few decades. Once considered a savior of the working class, today the potato is credited with their undoing. With obesity and diabetes rates soaring, especially among working class people, the potato in all its processed forms is seen as a villain. To some extent, this reputation is well-earned. Potatoes represent some of the highest glycemic index foods available, for example. Basically, this means that potatoes tend to impart their carbohydrates into the body more rapidly than most other foods, resulting in a greater likelihood of weight gain and the development of diabetes, all else being equal.
But the story doesn’t end there. High glycemic index foods aren’t necessarily bad for everyone, especially as part of a balanced diet. Potatoes generally contain high quantities of fiber, vitamins C and B6, as well as minerals like potassium and manganese. So, with your high carbohydrates also come other densely packed nutrients. As a result, while a pre-diabetic eating potato chips on the couch is definitely a bad thing, he may actually be well-served eating a seafood and bean-heavy fisherman’s stew that also happens to contain a sensible amount of certain varietals of potatoes.
And not all potatoes and potato cooking techniques are created equal, either. Keeping the skins on (but scrubbing them to remove dirt, grit and pesticides) retain about half the fiber of the potato as well as helping to retain its vitamins during cooking. Furthermore, when cooked potatoes are cooled overnight, the starches partially crystalize making them more resistant to digestion. This lowers the glycemic index by about 25 percent, even after reheating. So, there are things you can do to your potatoes to make them even better for you.
The Details Matter
But you didn’t come here just to learn about how to make potatoes healthier. You came here to learn how to make them more delicious. Unfortunately, there isn’t a one set of things you can do every time to make your potatoes more delicious across all dishes and the reason is because potatoes vary considerably. To give you an overview of all of the problems facing the would-be expert potato chef, I’ve laid out some of the complexities of potato science.
Picking the Right Potato
In general, there are three classifications of potato varietals for the concerned chef that vary by starch and moisture content. On one side are the high starch, low moisture potatoes, those that coat your knife with a milky liquid when cut. These include your russets, for example, and they’re ideal for crisping up in the fryer or while roasting. On the other side of the spectrum are the low starch, high water content potatoes like red potatoes. These are great for stews and braises because they tend to hold their shape particularly well at temperature. (As a brief aside, you can further improve their shape retention by poaching them for 20 minutes at 55 °C (131 °F); this activates enzymes which reinforce the potatoes cell walls.)
There are also potatoes like the Yukon Gold, which sit in between the two extremes. They have a decent amount of starch and are somewhat moist. These are best for scalloped potatoes, mashes or casseroles where you want plenty of starch but not too much browning. Less starch in mashes also helps to avoid gluey, sticky mashed potatoes which are caused by overmashing when too many cells are crushed, releasing all of their gummy starch.
Not only do potatoes vary across varietals in their starch and water content, but they also vary among varietals. For example, depending on where and when a russet was grown; the conditions of storage and the duration for which it was stored, a russet can vary in flavor, simple sugar versus starch content, and starch density (due to a loss of water).
Potatoes as Living Systems
The reason for this is that your russet is alive. The ideal conditions for your potato to live a happy life in storage is in a well-ventilated area in complete darkness, between 90 and 95 percent humidity and at a temperature between 7 °C and 10 °C (45 °F and 50 °F). In lower humidity environments or poorly ventilated areas, the potatoes just risk drying out or growing disease on the skins. It gets more complicated from here though.
If you expose your potato to too much light, it starts to produce chlorophyll and the alkaloids solanine and chaconine, turning green and sprouting, pushing the flavor to bitter. If it gets green enough, the alkaloids can even make you sick or kill you. But don’t worry about slightly green-tinted potatoes. You can cut off the green portion and enjoy the rest. Potatoes have to get very green before they can do anything but give you some mild gas.
Potatoes can also turn slightly sweet if you store them below 5 °C (41 °F). This happens because, in the refrigerator, the normal metabolism of a potato changes (essentially going into crisis mode), causing them to convert their starches into sugar. This process can be reversed, however, by storing the potato at the sweet spot of between 7 °C and 10 °C for several days before cooking.
There are reasons you might want those sugars, however. For example, you’d want a fair amount of sugar to better brown your potatoes while roasting or frying. In the case of roasting, a couple days in the refrigerator will develop enough sugar to really help browning in the oven. In the case of frying, overnight should do, since too much sugar can burn in the fryer. Before cooking, however, bring the temperature of the potato back to room temperature to avoid dark spots developing on your cooked potatoes. The spots are concentrations of acrylamide, an aesthetically displeasing and arguably dangerous carcinogen. The reaction that creates acrylamide does not occur in cooking when the potatoes start at temperatures above 7 °C.
So Here’s What You Do
- Store your potatoes in a well-ventilated area in complete darkness, between 90 and 95 percent humidity and at a temperature between 7 °C and 10 °C.
- Use high starch potatoes for frying or roasting to get them nice and brown. Use low starch potatoes for stews and use the middle of the row potatoes for scalloped potatoes or potato casseroles.
- Also, use middle of the row potatoes for mashes as they are less likely to get gluey or sticky as a result of overworking them. To avoid overworking them, mash them just enough to break them down.
- If you’re going to fry the potatoes, put them in the refrigerator overnight. If you’re going to roast them, keep them in there for two days. Always let them rest and warm them up before cooking them to avoid black spots and carcinogenic chemical reactions.
- You can further improve potato shape retention in stews by poaching them for 20 minutes at 55 °C. This activates enzymes which reinforce the potatoes cell walls.
- Lower the glycemic index when you can. If you are going to stew a potato, cook it first and refrigerate it overnight if you can. Same goes for casseroles and mashes.
- To better retain nutrients, keep the skins on, but be sure to scrub the potatoes to remove dirt, grit and pesticides.
Above are just the general tips, but so you can get a sense for the level of detail required to just to make a humble roasted potato perfect, I offer the following recipe. We start, of course, with russets that we refrigerate for two days, but rest on the counter to warm up before we cook them.
I use a method of first boiling the potatoes to the extent that they begin to dissolve, creating a microscopic, porous and lacey layer of potato flesh and starch that maximizes the surface area of the potato, increasing the amount of area available for crisping. Although the boiling will nuke some of the vitamin content, more crisping area means crispier, more satisfying potatoes. I also include vinegar in the boiling water to help the process along by denaturing some of the proteins holding the potato together. It also adds a satisfying vinegar flavor. To make it even crazier, I dry the potatoes out in the oven a bit and then coat them with seasoned potato starch before a final browning. This creates the thickest, richest, most satisfyingly crispy brown outer layer on the potatoes and a beautiful, flakey and moist center. They’re absolutely game changing.
Have a question? Ask me anything!
1 kg (3 medium or about 35 oz) russet potatoes, cut into 2 cm cubes, skins on
30 g (about 1 oz) fine potato starch
10 g (about 1 tbsp) fine garlic powder
2 g (about 1 tsp) finely ground cayenne pepper
3 large thyme sprigs
30 g (about 1 tbsp plus a small additional amount for seasoning) kosher salt
10 g (about 1 tbsp) distilled white vinegar
One large sprig of cilantro or parsley, roughly chopped
Two cloves of oven crisped garlic
Try substituting half of the russets for another varietal from the middle of the row, such as Yukon Gold or a purple potato for a variation of flavor and texture.
A variation of this potato recipe appears as a component in my Galician-Style Grilled Octopus recipe. I recommend trying that out as well.
- Pour 1 L (about 34 oz) of cold tap water into a large saucepan. Add the vinegar and salt, stirring to dissolve. Add the potatoes and bring the water to a boil over medium-high heat. Maintain a medium simmer until potatoes are very tender and the edges appear slightly lacey as the potatoes break down, about seven to ten minutes. Remove potatoes and set aside. Discard liquid.
- Preheat oven to 150 °C (301 °F). Grease a quarter baking sheet with a small amount of olive oil. Arrange the potatoes in a single, even layer on the baking sheet. Place in the oven and bake until just dry, about 10 minutes.
- Increase oven temperature to 250 °C (482 °F). Mix the potato starch, garlic and cayenne and a pinch of salt in a bowl. In a second, large bowl, coat the cubed potatoes with the starch mixture. Coat with about half the olive oil. With a large spoon, toss the potatoes until well coated and the edges and corners of the potatoes erode slightly. Again, arrange the potatoes in a single, even layer on the baking sheet and pour the remaining oil uniformly atop the potatoes. Arrange the thyme sprigs evenly spaced across the surface of the potatoes.
- Place on the middle rack and roast until the tops are crisp and golden brown, about 15 minutes. With a fish spatula or other thin metal spatula, flip the potatoes and bake until the final side is crisp and golden brown, another 10 minutes.
- Remove from the baking pan and toss with a little salt, if needed, and plate.
- If desired, top with chopped cilantro, parsley and/or oven crisped garlic. Serve immediately as a side dish or as a delicious snack.