A Brief History of Foods: Sweet Chestnut
Some friends of ours have made some sweet chestnut flour and, knowing that our first passion is for Roman history, asked us for some Roman recipes using the flour. Not able to readily recall any such recipes, we set about researching sweet chestnuts and their culinary use.
According to its Wikipedia entry: “Castanea sativa, the sweet chestnut , is native to Southern Europe and Asia Minor, and widely cultivated throughout the temperate world. A substantial, long-lived deciduous tree, it produces an edible seed, the chestnut , which has been used in cooking since ancient times.”
History In Andrew Dalby's excellent book "Food in the Ancient World from A to Z", the sweet chestnut was “one of a group of fruit trees that spread rapidly in western Anatolia and southern Europe after about 1,200 BC…The ancient Greeks ate them as Tragemata, the foods eaten with wine at dinners.” 
One of the earliest references to sweet chestnut occurs in Theophrastus’ “Enquiry into plants” (Historia plantarum) . He comments on the cultivation  of chestnut as a wild tree (probably also coppiced) to produce timber (both for inside construction and for external use) and charcoal . In all of his work, there is only a single indirect reference to the use of the fruit, when the author compares the taste and the sweetness of chestnuts to beechnuts .
Conedera (2004) asserts the ancient Greeks were fundamental in developing the cultivation of chestnut, both for its wood and its fruits, but not on a large scale . Moreover, the colonisation of the Italian peninsula by the Greeks (Magna Graecia) may have contributed to the transfer of the techniques for chestnut cultivation to the Latin world in much the same way as the Greeks introduced the grape vine and olive cultivation. Further clues pointing to this theory can be found in the work of Pliny the Elder, who mentions only Greek colonies in connection with sweet chestnut cultivation.
Evidence for chestnut cultivation and use in the Roman Republic and Imperial periods is scarce before AD 1, not only in the dateable pollen profiles but also in pre-Christian Latin texts. Interestingly, despite the spread of the Roman Empire, no centre of sweet chestnut cultivation outside the Italian peninsula in Roman times has been identified. It was not until the early Middle Ages that the widespread use of chestnut in western Europe started, before eventually flourishing in the late Middle Ages.
Recipes By the end of the pre-Christian era, however, there were varieties of good quality chestnut being produced. Cultivated for their ease of peeling, chestnuts were eaten after being boiled or roasted. That chestnuts were part of the diet of the Romans, at least in the areas of the Greek colonies, is confirmed by the remains of carbonized chestnuts at the Roman Villa Torre Annunziata, destroyed by Mount Vesuvius’ eruption in AD 79 . Unlike the chestnuts themselves, however, recipes using them from the same period simply have not survived. As Dalby (2004) notes, sweet chestnuts were dried and milled into flour from which a form of bread was made . In Rome, according to Pliny the Elder , chestnut bread was used as a substitute to more typical fare by women when fasting  but, in typical Pliny style, he does not elaborate further.
As its name implies, chestnut flour will have a sweetness that may have made it ideally suited to pastries and cakes. The best-known surviving Roman recipe collection, that of Apicius, is missing the books on desserts, however. Had these survived, then maybe we would have had the evidence for sweet chestnut use. Sadly, as they do not, we can only speculate.
Fortunately, recipes abound on the internet for chestnut flour bread. Indeed, being gluten-free, making and using chestnut flour is a good option for those with celiac disease or other gluten intolerances or allergies. For the same reason, however, it can be a challenge to bake with as, with no gluten, it will not rise on its own. The collective wisdom advocates that chestnut flour tastes better when mixed with other flours, especially bread flour, to create a dough. Allow about ten per cent chestnut flour in bread. A chef’s top tip is to mix chestnut flour with egg and water to make a batter and use it that way. If you use sparkling (carbonated) water, this will make a much lighter batter. Chestnut flour, or a batter thereof, can be mixed (to taste) for making cakes and biscuits, or a small amount can be added to pasta doughs, to achieve a sweeter flavour.
Pick your own In late October, when they fall in large numbers, wild British sweet chestnuts are fully ripe. If do you forage for them, then do not confuse edible sweet chestnuts with the unrelated (and inedible) horse chestnuts (also known as conkers). In addition, look for the glint of shiny dark brown nuts rather than the paler ones as the latter are unripe and will quickly shrivel.
Hang the wild chestnuts in a net bag to air in a cool dry place for a couple of days after foraging them. By doing so, some of the starch will be converted to sugar thus giving a sweeter nut.
Preparation To peel chestnuts, soak them in water for 30 minutes, then score each with a small knife down the plump side. Roast at 225°C/425°F/Gas 7 for about 25 minutes. Keep warm with a tea towel while you peel away the hard, outer shell and the softer inner brown skin (warm nuts peel more easily than cold ones). For a faster method, slit the rounded shell of the nut, bring to the boil in plenty of cold water and cook for 20 minutes. Leave the nuts in the hot water so that they stay warm and soft as you peel. Do remember that dried chestnuts must be soaked in water for at least eight hours before use in cooking.
1. Other common names include "Spanish chestnut", "Portuguese chestnut" and "marron" (French for "chestnut").
2. Castanea sativa is only distantly related to the horse chestnut (Aesculus hippocastanum). The horse chestnut bears similar looking seeds (conkers) in a similar seed case, but these are not palatable to humans.
3. Dalby, A. (2003), Food in the Ancient World from A to Z, Routledge, London, p. 82.
4. Theophrastus was a philosopher and naturalist, a native of Eresus on the Island of Lesbos. He went to Athens at a young age and initially studied in Plato's school. After Plato's death, he attached himself to Aristotle who took to Theophrastus in his writings. When Aristotle fled Athens, Theophrastus took over as head of the Lyceum, a temple dedicated to Apollo Lyceus. Theophrastus presided over the Peripatetic school for thirty-six years, during which time the school flourished greatly. He wrote on numerous subjects drawing on his varied experiences. His “Enquiry into plants” (Historia plantarum), divided into six books, deals with the classification and the description of the botanical world then known. As a consequence of his works on plants, Theophrastus is often considered the father of botany.
5. The Latin term sativa means "cultivated by humans".
6. Conedera, M. (2004), "The Cultivation of Castanea sativa (Mill.) in Europe, from its origin to its diffusion on a continental scale", in Vegetation History and Archaeobotany, 13 (3), p. 167.
7. Op. cit.
8. Op. cit.
9. Dalby, A. (2003), p. 82.
10. Born in Como (northern Italy) around AD 23/24, Gaius Plinius Secundus was a Roman author, a naturalist and natural philosopher, and a naval and army commander of the early Roman Empire. Probably educated in Rome, Pliny was killed by the eruption of Mount Vesuvius in AD 79. his Naturalis Historia (“Natural History”) is a compilation of the extant knowledge about art, science and civilization in 37 books.
11. Gaius Plinius Secundus, Naturalis Historia (“Natural History”), Book XV, xxv. 92.
12. Meyer, F.G. (1980), “Carbonized food plants of Pompeii, Herculaneum, and the Villa at Torre Annunziata”, Economic Botany 34, pp. 401-437, quoted in Conedera (2004), p. 172.