You cannot easily duplicate ideal storage conditions for potatoes in your home so don’t buy more than what you can use in a few weeks. Thick-skinned potatoes keep longer than the thin-skinned varieties.
If stored above 50°F (10°C), potatoes begin to sprout, which makes them flabby and more susceptible to decay, even though most storage potatoes are chemically treated to delay (but not stop) sprouting.
If you store them in your refrigerator, potatoes turn sweet and taste unpleasant. Here is what happens. After harvesting, the still-living potatoes continue to breathe and to convert their starch to sugar at a slow rate, the way they naturally do. When you quickly cool them to refrigerator temperature, potatoes slow their breathing rate (because breathing slows at cooler temperature), but the reaction that converts starch to sugar continues at the same rate.
They cannot use up the sugar fast enough, it accumulates and refrigerated potatoes taste too sweet. The sugar converts back to starch if you return the potatoes to room temperature, but the process doesn’t reverse completely.
Because of the increased sugar, refrigerated potatoes are particularly poor choice for frying. The sugar caramelizes in the hot oil, the potatoes tend to burn and become bitter.
You should store potatoes under well-ventilated conditions so they can continue to breathe. That is one reason why the plastic bags in which they are sold always have little breathing holes.
For long-term storage, add an apple to the potatoes. The presence of apple preserves potatoes longer in firm, healthy conditions and discourages sprouting. Apple gives off ethylene gas and alcohol while it breathes that suppress sprout formation.
Cooking potatoes is one of the first thing a new cook learns. Not much to it but keep in mind a few points:
¨ use just enough water to cover (to leach minimum of nutrients)
¨ salt the water, otherwise you leach the natural salt from the potatoes and they taste flat
¨ don’t overcook or undercook, so keep testing with the point of a knife or skewer; cooking time is around 15 minutes for diced potatoes but varies with your location and how large the dices are. Average-size whole potatoes cook in about 30 minutes, large ones 45 minutes.
When baking potatoes, don’t cover with aluminum foil unless you like soft skin. In foil potatoes steam instead of bake. But oiling or greasing the skin before baking promotes browning and crispy skin. Pricking the skin with a fork or knife before baking is also a good idea to prevent a possible explosion in the oven that could happen if the potatoes have tough skin and the built-up steam inside cannot escape. It makes quite a mess in the oven.
French frying is a messy operation even with a home deep-fryer but properly-made French-fried potatoes are delicious. In deep-frying you reduce the high moisture content of potatoes from the original 78 percent to about 2 percent.
The moisture turns to steam in the hot oil, desperately trying to escape while spattering oil everywhere, creating a mess. As bubbles of steam burst when emerging from the surface of oil, they produce a small hissing sound. All the bursting bubbles together act like an orchestra to create that pleasing sizzle with its anticipation of that heavenly deep-fried taste.
The steam escapes first from the hottest part of the potatoes, the surface which is in direct contact with the hot oil. Then, as the center part of potato gets hotter, moisture starts turning to steam that escapes through the outside part. Eventually not much water remains in the potato and the sizzling dies down.
The outward pressure of escaping steam keeps the oil from seeping into the potatoes, but the steam also cools their surface to prevent burning (evaporating water cools, like your skin after coming out of the pool). When most of the moisture has boiled off, the potatoes become vulnerable to burning but also start absorbing more oil.
Oil temperature is critical. If the oil is too hot, the surface of the potatoes burn before the inside is properly cooked. If the oil is too cool, the escaping steam doesn’t have enough pressure to keep excess oil out of the potatoes. The correct deep frying temperature is 375°F (192°C).
Unless you have a thermometer or a thermostat on your deep-fryer, there is no easy way to judge that. Various home methods, such as browning a certain-size bread cube in so many seconds that some cookbooks suggest, are not accurate enough when oil temperature should be preferably within 15° of the ideal. For that reason the results of home French-frying is not often as satisfying as French-fried products in a good fast-food joint.
The best method of deep-frying potatoes is the two-stage method. In the first stage you cook the potatoes in oil at a lower temperature, 325°F (161°C), until they are limp but not brown, about 3 to 4 minutes. In this stage the oil is hot enough to gelatinize starch, in other words, to cook the potatoes. In the second stage the already cooked potatoes quickly brown at 375°F (192°C).