Why do McDonald's fries go rock-hard after sitting out for a while?

Why do McDonald's fries go rock-hard after sitting out for a while?
Our Answer
McDonald's South Africa (SA) famous fries harden after being left out, because of the limited amount of moisture remaining in them after cooking. In the same way that the surface of a baked cake or toasted bread will harden, so do our French fries.
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McDonald’s South Africa |