The process of shocking root vegetables to cool them quickly in ice water versus letting them cool to room temperature on their own has been a topic for discussion by many great chefs. Some chefs believe that shocking any root vegetable will produce an inferior product, while almost every single chef believes more specifically that shocking potatoes is a bad practice. We decided to experiment with this to try to find out whether or not it is true.
First, we did some research and found the potato to have a very interesting and extensive history. There is evidence of its cultivation and domestic use in Peru as far back as 3000 BC. Some researchers believe that at one time Peruvians probably worshiped the potato, for potato-shaped pottery has been found dating from the second century AD. (Bareham, 3) The first European encounter with the potato was believed to be in the 1500s through a Spanish explorer. During the early 1600s, the potato had spread all over the world, becoming the staple food of Ireland around 1650. The potato is now recognized as the third most important crop in the world - for both human and animal consumption.
The Solanum tuberosum esculentum (Latin) is also an extremely nutritious product. It has very few calories (about 160 per 8 ounces of steamed potato), and even when made into mashed potatoes with the classic combination of milk and butter, the calories only build up to about 280. This holds true in almost every occasion with potatoes except potato chips, which consist of about 500 calories if you had an amount of those equivalent to the amount of mashed potatoes in the previous example. There are many vitamins and minerals stored in or just below the skin, which is why it's best to cook the potato in its skin (see results below). We've heard it said that salt draws out these vitamins and minerals, and that's why we should add salt after the cooking process rather than in the cooking water...though we don't know that this hypothesis has ever been tested. (Bareham, 7)
Our hypothesis was that only starchy root vegetables are affected by shocking. We believe that testing beets, carrots, turnips, and potatoes will give us some type of understanding on what happens to root vegetables when they are cooked and shocked.
So that we would be able to tell if there are any differences between shocking root vegetables or not shocking them, we had a wide variety of variations, broken down into four categories. For each vegetable listed above, we had one quarter of the total amount of that vegetable that was peeled and sliced. It was then cooked in a control amount of 2 quarts of water with 1 tablespoon of salt and cooled by the shocking method. The second variation was another quarter of the amount of each vegetable that was peeled, sliced, cooked in the control, and cooled slowly in a refrigerator. The third variation was another quarter of the total amount of vegetables we had, not peeled or cut, cooked in the control, then being cooled by shocking. The fourth variation is the same as the third, but the vegetables were cooled slowly in the refrigerator.
After doing this experiment, we found that the whole, cooked vegetables with the skin on tasted better and kept their color better as well. The differences between the shocked vegetables and the non-shocked vegetables were very few. When vegetables are heated, the cells expand and split apart when cooking. When the vegetable is shocked, the cells quickly contract tightly, squeezing out water and some color pigment, making them crisper as well. With starchy vegetables, the same thing happened, but the sliced potatoes tasted "waterlogged" (as many of our taste-testers mentioned), making for a brittle and unwanted texture.
We immediately followed the experimentation process with a survey, in which the only noted differences between the shocked and unshocked vegetables were within the potatoes only, which were made note of above.
Through all our research, we found no information supporting the idea that shocking root vegetables is bad, with the exception of potatoes. Potatoes are said to fall apart when shocked, lose taste, become less sweet, and lose a great deal of nutrients. With one exception (that being the sliced potatoes being waterlogged), we found this statement to be false. Our research showed that potatoes may lose some of their nutritive value when shocked, and while that may have been true, we were unable to test it.
In conclusion, whether root vegetables are shocked or not really doesn't matter. The only difference is that it's a big waste of time to slowly cool vegetables. Plus, when vegetables are cooled slowly, the center becomes overcooked, which is unwanted in any restaurant. We feel that shocking vegetables is a good practice for almost any restaurant. This will allow them to parcook their vegetables before service, cool them quickly so they don't overcook, and finish them off during service for the customer.
Tested by Ira Krizo and Charles Lacad
Written by Ira Krizo
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