As far as nuts go, acorns enjoy an unusual composition. Acorns are largely made up of starches and fiber whereas most other type of nuts (hazelnuts, walnuts, pecans, almonds, etc.) are largely made up of proteins and oils/fats. Because of this structure, acorns have a unique property among nuts – they can actually be malted.
The acorn itself is very similar in content to barley. It is 72 to 80 percent starch, 8 to 12 percent protein, and has a low oil content. One of its major drawbacks is that, like the potato, it contains high concentrations of the enzyme polyphenol oxidase. Therefore, the beers made with acorns will not be of the lighter variety. In test mashes the color comes out to be a brown shade along the line of a Vienna or Oktoberfest-style beer.
Acorns are among one of the more ancient of nuts enjoying not just a nutritional role, but a mythical one as well. “In Greece, the oak too was reckoned the tree from which men first sprang; they called it the ‘first mother’, which fed men, mother-like, with her own acorns.” (Ovid)
“Acorns, too, were a charm against lightning, and ornamental designs used to be made from them and put in cottage windows.”
Prima Ceres ferro mortalis vertere terram instituit, cum iam glandes atque arbuta sacrae deficerent silvae et victum Dodona negaret. Ceres was the first to instruct mortals how to turn the soil with iron, when once the acorns and the wild strawberries of the sacred forest were failing and Dodona was refusing food.
Virgil implies that Ceres’ grain superseded acorns as the foodstuff of choice. “Liber et alma Ceres, vestro si munere tellus Chaoniam pingui glandem mutavit arista.“ Virgil, 1.7-8, c.30 BC. A loose translation is, “Ancient deity and kind Ceres, who by your bounty aided the Earth in replacing Dodona’s acorn with plump grain.” This implies that acorns were the food of choice for mankind prior to the development of agriculture.
In the 15th century, we see acorns mentioned as a principle ingredient in pottage – a hot stew similar to porridge. “Chikeney. Do almond mylke yn a pott. Take cornels of okekornes [acorns] rostyd; grynd hem, draw hem with wyn or ale. Do therto a grete porcyon of sigure, saundres, & safron & othri poudris, & seson hit up with poudres; & take the schelles & set abovyn.”
Sweet acorns are indeed the best to eat, as they have a lower tannin content. Their low fat and high carbohydrate content make them a suitable food for both humans and animals; pounded and washed in running water, boiled or roasted, they can be quite pleasant. When ground they provide a flour, used in times of hardship, which has given this benign food a bad name.
“Meanwhile, in an anonymous 16th-century survey (Descrittione dell’isola di Sicilia, 1546), listed… as typical of Val Demone [ed. note: a historical and geographical region encompassing the north-eastern third of Sicily], were acorns, olives, grapes, chestnuts, almonds, walnuts, pine nuts, hazelnuts, figs, pears, cherries, apples, plums, peaches, and mulberries.” [bold added for emphasis.]
Acorns in mead are referenced in a kenning within the Ancient Lay of Gudrun, referenced as part of the Volsunga Saga. Although brown-burnt acorns are listed here as an ‘ill’, malted or fresh acorns would not be so. Given that ‘blood of all the wood’ [sap] is also listed as an ill when maple and birch sap are not considered so, and that ‘god-doomed dead beasts inwards’ [diseased entrails] is listed as an ill when non-diseased animal innards are part of the daily diet, I contend that the variants listed here are abominations of standard ingestible ingredients. Thus, the inclusion of acorns in the list implies that unburnt acorns are in fact used in food and/or beverage production.
In that mead were mingled
Many ills together,
Blood of all the wood,
And brown-burnt acorns;
The black dew of the hearth,
And god-doomed dead beasts’ inwards
And the swine’s liver sodden,
For wrongs late done that deadens.
 Watts, pg. 203
 Watts, pg. 228
 Boyd, pp.73-4
 Maro, 1.7-8
 Hieatt, pg. 71. The recipe is cited as being from a 15th century source.
 Riley, pp. 7-8.
 Riley, pp. 498-9.
 (Sigfusson) Thorpe, pg. 216
Boyd, Barbara Weiden (1997). Ovid’s Literary Loves: Influence and Innovation in the Amores. Ann Arbor: University of Michigan Press.
Hieatt, Constance B. et al (1988). An Ordinance of Pottage: an edition of the fifteenth century culinary recipes in Yale University’s MS Beinecke 163. London: Prospect Books.
Maro, Publius Vergilius (c. 29 BC). Georgics. Translated in Virgil: Georgics: Volume 1, Books I-II. Richard F. Thomas (ed.) Cambridge: Cambridge University Press, July 1988.
Riley, Gillian (November 2007). The Oxford Companion to Italian Food. Oxford: Oxford University Press.
Sigfusson, Saemund (c. 11th century). The Elder Eddas. Translated by Benjamin Thorpe (1906). London: The Norroena Society.
Watts, D. C. (May 2007). Dictionary of Plant Lore. Cambridge: Academic Press.
Whistler, Randy (November 1997). “The Adjuncts: Malt Madness”. Brew Your Own. Retrieved 23 June 2016, from https://byo.com/hops/item/1463-the-adjuncts-malt-madness.