If you’ve served the military and got to enjoy the scrumptious veggie omelet (also fondly called vomelet) or maybe pizza (that we also wrote about here), then you’re no doubt familiar with the “rock or something” on the Flameless Ration Heater. It actually is a very nifty device as cooking fires give off smoke and light that would give away your position to the enemy in combat, and you are just trying to eat, not bring an artillery barrage down on your unit, right?

Flameless Ration Heater: Because At Least It’s Hot Garbage You’re Eating

Meal, Ready To Eat does not have the best reputation, and they don’t for a reason. But do you know what’s worse than eating a weird, mucky wad of food out of a foil bag? trying to ‘hork’ it down stiff and nearly frozen. Thankfully, the MRE comes with a flameless ration heater, so you could at least eat hot garbage. Here’s the illustration of how you should use it based on its packet:

FRH illustration. (Ashley PomeroyCC BY-SA 4.0, via Wikimedia Commons)

Okay, but how does this thing heat up?

Science. This self-heating food packet contains finely powdered magnesium metal, alloyed with a small amount of iron and table salt. Once you add water, it melts the salt that would then act as an electrolyte that would turn the magnesium and iron particles into tiny short-circuited batteries that burn out quickly and produce heat in the process. It could raise an eight-ounce MRE main meal by 100 degrees Fahrenheit in just 10 minutes.

Resting Your Food Or Something On A “Rock or Something”

Lauren Oleksyk, the team leader of the Food Processing, Engineering, and Technology Team at Combat Feeding, could answer the question.

As she said in an article written by The Army:

We were designing the FRH directions and wanted to show an object to rest the heater on, (Don) said, ‘I don’t know. Let’s make it a rock or something. So we wrote ‘rock or something’ on the object, kind of as a joke.

And so what originally was a joke was printed on the illustration instructions on how to activate the FRH.