25 April 2011

Root cellar culinary science

When my mother was growing up on a farm in rural Olmsted County, Minnesota, the farmhouse had a large root cellar, where vegetables were stored for the winter.  There was a large pile of sand in the corner, in which carrots were buried, and separate piles for potatoes.

In my childhood home in suburban Minneapolis thirty years later in the 1950s, we had good kitchen refrigeration (though no air-conditioning), but in addition to a refrigerator and storage freezer, we still maintained a de facto root cellar.  The basement was partitioned into a play area and a utility area which held the furnace and water heater; one corner of that unheated area was used for storage of potatoes, which we bought by the gunny sack.

Today I learned, from an article in the Wisconsin State Journal, that winter storage of vegetables may improve their sweetness -
"This is a phenomenon called cold-sweetening," says UW-Madison horticulture professor Irwin Goldman. As plants produce sugars through photosynthesis, most are combined and stored in the plant as starches and other large polymers. But in response to cold temperatures, some plants break down some of their energy stores into "free" sugars, such as glucose and fructose, and stash them in their cells to guard against frost damage. Sugar dissolved in a cell makes it less susceptible to freezing in the same way that salting roads reduces ice...

Cold-sweetening occurs in many cold-tolerant vegetable plants. Local consumers may have experienced it in Wisconsin-grown winter spinach, but it also happens in beets, broccoli, carrots and even potatoes.

In fact, Goldman says, cooks may find that cold-stored potatoes turn brown when cooked, due to caramelizing of the extra sugar. This can be avoided by moving cold potatoes to warmer storage areas to recondition them and allow the sugars to convert back to starch before cooking them.
The photo, from the Minnesota Historical Society, shows the large root cellar at the Oliver H. Kelley farm, a historical farm preserved for educational purposes.

10 comments:

  1. What are the big white round things? Some kind of squash?

    --Swift Loris

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  2. Swift, you may not have seen the movie...

    http://en.wikipedia.org/wiki/Invasion_of_the_Body_Snatchers

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  3. AIEEEE!!

    (grin)

    C'mon, Minnesotastan, what are they really?

    --Swift Loris

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  4. I've not been there, so I can't say for sure. I would guess either very round, pale pumpkins, or perhaps some type of large gourd?

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  5. they look like puffballs

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  6. Actually, they look like just plain ordinary pumpkins to me, but what do I know.

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  7. Do I need a pile of sand to store my potatoes? And would it be a problem if the cellar were very moist?

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  8. The sand wouldn't be mandatory, pom; they could just be stacked like the pumpkins in the photo. But sand would offer two advantages. It would conduct heat, so if the floor and the walls were colder than the air, having carrots etc in the sand would keep them cooler than a pile of them would be. And it would keep the temperature more constant rather than fluctuating up and down during the day/night.

    I would guess humidity would be a disadvantage for storing vegetables, but I can't say that with certainty. Try Googling humidity and root cellar.

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  9. most vegetables need cool temperature and HIGH humidity to store well.

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  10. JOE SAID - That's right. Generally speaking, vegetables and fruits do need a high level of humidity to maintain their moisture levels. Root cellars work best with a damp dirt floor (not concrete). If you want some good info on storing food the old way, get the book "Root Cellaring" by Mike and Nancy Bubel. Its a very good book and worth every cent. JOE

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