Thanksgiving food science: Five holiday flubs explained

Mashed potatoes

We’re advised each Thanksgiving not to whip mashed potatoes with a mixer because they’ll get gummy. What’s happening there?

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Thanksgiving recipes from the White House: First-family favorites like Laura Bush’s green beans or Mamie Eisenhower’s pumpkin pie add personality to the holiday spreads in America’s most famous home.

Video

Washington Post food editor Bonnie Benwick brings some tips of the trade to The Fold set and shows us how to bring our best mashed potatoes to the Thanksgiving table.

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Potatoes are about 79 percent water and 15 percent to 20 percent starch. Success or failure in mashing is primarily a matter of how you treat that starch.

Inside each of the potatoes’ cells are hundreds of granules that under a low-powered microscope look like plump little pillows. Inside those granules is a clear, thick paste of starch that the plant manufactured during its photosynthesis days as nourishment for its future generations.

Break open too many of those granules, letting too much of the starch paste leak out, and you’ll end up with pasty mashed potatoes. So unless you want to use the result for affixing wallpaper, don’t use a food processor or a blender. Their high-powered blades can reduce the potatoes to a puree, which is great for juicy, non-starchy fruits and vegetables. But by the time a potato is squished to that degree, most of its starch granules have been torn open, spilling their gluey contents.

Mixers can do both mixing and beating/aerating. However, beating potatoes in a mixer in an attempt to make them fluffy is almost as bad as using a blender. It’s okay to use a mixer on very low speed to distribute additives such as butter and milk. But beating them too vigorously will break down their starch granules into glue just as a blender does.

The best tools for mashing starchy potatoes such as russets or Yukon Golds (the waxy reds are not preferable for mashing) are — you guessed it — ricers and mashers. Ricers look like overgrown garlic presses. Cooked potatoes are extruded through a plate with holes approximately the size of grains of rice. This does little damage to the starch granules, thus keeping the potatoes from turning gummy.

Lacking a ricer, I prefer the kind of potato masher that has a flat plate perforated with square or rectangular holes through which the potatoes are extruded, just as in a ricer. But use a straight up-and-down motion; sidewise swipes can squish granules open, resulting in glue.

The frozen bird

OMG! I forgot to defrost the turkey. It’s still in the freezer and my Thanksgiving guests will be arriving in six hours. I called my mother and all she did was LOL. Then she said, “Don’t worry. Just roast it without thawing it. I’ve been doing that for years.” 

People do this every year, and reputedly a tender, juicy bird is ready in about five hours. So if you have to deal with a frozen turkey on Thanksgiving morning, all is not lost. Put on an apron and get cracking. But whatever you do, don’t try any quick-thaw schemes such as microwaving it or soaking it in hot water. You would be asking for food poisoning, because the turkey’s surface would warm first and remain at bacteria-friendly temperatures for hours.

An obvious concern is that the skin will burn while the rest of the bird remains underdone. And wouldn’t the bag of giblets packed inside the cavity leak bacteria-laden juices that won’t reach a microbe-lethal temperature?