Thursday, March 29, 2012

The Great French Fry Experiment

The Conscious Shopper and family attempt a science experiment.

When my second grader announced that he was looking for ideas for his school science fair project, I knew just what he should do. A couple years ago, Jess of Sweet Eventide posted here at the Booth about starting an experiment to see if homemade french fries would decompose faster than fast food fries...only she never updated the post with the results!

The time had come, I decided, to find out for ourselves if fast food french fries really never decompose, as the Internet claims.

We bought a container of McDonald's fries and made a batch of homemade fries. Then we divided up the fries into glass jars. My son took photos and careful notes on the decomposing fries every week or so. Here's what they looked like after one week:

And here's what they looked like eleven weeks later:

Hopefully, it's obvious from the photos that the homemade french fries decomposed faster than the McDonald's fries.

However, when we sat down to do some research a week before the science fair (we are not proper scientists), we dug up some very interesting information. McDonald's french fries contain the preservatives citric acid and sodium acid pyrophosphate. Plus, the oil they're fried in contains TBHQ, an additional preservative. You obviously won't find those additives on the ingredients list of homemade french fries, and they're arguably not good for our bodies. But our research indicated that they are actually not the reason that McDonald's french fries take such a long time to decompose.

It seems that the real culprits are 1) FAT and 2) SALT. Deep-frying the potatoes and then dousing them in huge amounts of salt removes almost all of the moisture in the fries, and the process of decomposition requires some moisture.

Which is why, it turns out, my family's french fry experiment was flawed from the start. We put the fries in glass jars covered in cheesecloth, and after a few weeks, even the moisture in the homemade french fries had all evaporated. By the time we were ready to put our experiment on display, we had a couple jars of slightly moldy rocks. Instead, we should have put the fries in lidded containers and/or periodically spritzed them with water.

So I guess one of you readers needs to take on this experiment one more time, set it up properly, and find out for sure how much faster homemade french fries decompose compared to McDonald's fries. Any takers?

1 comment:

Clint Baker said...

Makes you wonder about Digestion of the fries? Yeeks!


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