Gruel may also be made from millet, hemp, barley, or, in hard times, from chestnut flour or even the less bitter acorns of some oaks.

Gruel predates the earliest civilizations, emerging in hunter-gatherer societies as a meal of gathered grains soaked in water.

This gruel also presented a viable medium for yeast to develop and ferment, serving as an important precursor for both bread and beer.

[4] Gruel was the staple food of the ancient Greeks, for whom roasted meats were the extraordinary feast that followed sacrifice, even among heroes, and "in practice, bread was a luxury eaten only in towns".

In the United Kingdom, it was a common remedy for the sick, relatively nourishing and easy to digest, and a standard component of the evening meal in British hospitals into the early 20th century.

Asian porridges/gruels are typically savory[citation needed], with meat or vegetables added and stock sometimes used as the liquid cooking element.

In modern Dutch, the plural word "grutten" still refers to de-husked, coarse ground grain and a traditional dish based on pearlbarley and blackberry is called watergruwel.