For 100 miles from source to sea, the River Tweed drains the Borders’ 18,000 square miles of landmass, collecting waters from the upland valleys of the Ettrick, Yarrow and Teviot, meandering across the fertile fields of The Merse flood plain, and onwards to the North Sea coast at Berwick-upon-Tweed.

Following the river’s epic journey through landscapes of mountain and flood, as the river and its tributaries carve and drain the Borders’ landmass, is one way to discover the story of the Borderland and its people – no less by the food and drink you encounter en route.

Start at the source, with one thing the Borders does best: beef. Beyond the ridge by Tweed’s Well lies the Devil’s Beef Tub, a cleft in the hills where Border reivers hid their stolen cattle, at a time 500 years ago when the borderland was ‘Britain’s wild west’, and criminal families robbed, raided, kidnapped and murdered in the lawless wilds between two hostile kingdoms, bequeathing us the words ‘bereave’. Where once a Borderer was loyal to family surnames like Scott, Douglas, Elliot, Maxwell, Armstrong and a hundred others, ‘lealty’ now belongs to town, attested each year by the community pride at the common ridings and contest on the rugby pitch.

Today’s Borderers retain the reivers’ taste for beef. Every town, and even the smallest village, sustains one or more of the Borders’ 30 independent butchers, all competing for custom with pies, sausages and haggis, and their beef and lamb is almost always sourced from local farmers at the weekly market at John Swan’s in St Boswells. Forsyth’s in Peebles exemplify the traditions of the Border butcher, still beside its own bakery, for customers to buy the day’s fresh meat, and then baked morning rolls, tarts and cakes next door.

Clooties in Peebles is skilled in the ancient Scots art of the steamed clootie dumpling: ‘skelped’ into shape, wrapped in muslin, and infused with spices, raisins, apples – and Traquair Ale, which Peebles chocolatier Ruth Hinks of Cocoa Black blends into an array of award-winning chocolates, sold at their café beside the town’s Cuddy Bridge. Beside jars of pear drops, rosy apples, sherbet lemons, rhubarb and custards, and other traditional sweeties in The Sugar Mountain on Peebles High Street, Ken Rodgie has created a striped mint-and-treacle confection of his own invention: the Peebles Peppery.

The novelist John Buchan spent happy childhood holidays in Broughton in Upper Tweeddale, and so chose to become the first Baron Tweedsmuir when ennobled. His adventure story Greenmantle inspired the name of Broughton Brewery’s first beer in 1980, which mixed water from the Talla Reservoir and malt from Simpsons in Berwick. Nine more bottles followed: The Black Douglas, The Ghillie, Old Jock, Exciseman’s 80/-, Merlin’s Ale, Scottish Oatmeal Stout, Angel Organic Lager, Border Gold Organic Ale and Champion Double Ale. Buchan’s hero of Sick Heart River, Sir Edward Leithen, is named after a tributary of the Tweed, the Leithen Water in the town of Innerleithen – where we find our next Border ales.

A brewery has existed at Traquair since Mary Queen of Scot’s visit in 1566, and when the craft brewery was revived in 1965 by the Twentieth Laird of Traquair, he used the same coach house and kit as in the 1700s. Every one of Traquair House’s annual 250,000 bottles of Bear, House and Jacobite Ale is fermented in unlined oak vessels between a hundred and two hundred years old, imbuing the beers with a tannic, woody depth, true to the taste of original porters and stouts. Jacobite Ale, brewed to commemorate the anniversary of the 1745 rebellion, is spiced with coriander using an 18th-century recipe unearthed in Traquair’s archives.

The fertile lowlands of Tweedside, Clydesdale and Perthshire’s Carse of Gowrie were Scotland’s orchards, growing native species of apple, pear and plum. The Stobo Castle, a cooking and eating apple, originated around 1900 near its namesake on the Upper Tweed, up river from an early Scots dessert pear, the Green Pear of Yair. Further downstream, the monks of Melrose Abbey began breeding the White Melrose apple in the sixteenth century, but not a patch on the scale of Jedburgh’s twelfth century abbey, which cultivated 30 varieties of Jeddart Pear, famed in London’s markets beside the town’s plums, apples and greengages. Alas almost all of Jedburgh’s orchards have disappeared – even the 400-year-old Queen Mary’s Pear Tree, planted by Mary Queen of Scots, blew down in a gale.

Apples and pears inspired Crookedshaws Farmhouse to create chicken liver pates of pear and pistachio, sage and apple brandy, and apricot and roasted pine kernel – winner of the 2009 Great Taste Awards. Laprig apple juice, available at Kelso farmers’ market, captures the tastes of the diverse varieties of apple in the Borders. Border Berries at Rutherford near Kelso is a third generation fruit farm owned by Harriet and Alistair Busby, growing fields of strawberries, raspberries, red and blackcurrants, tayberries and gooseberries in season, when families can pick their own, and enjoy fresh baking at the Tutti Frutti Café.

Near Abbotsford House on the banks of the Tweed, where Scotland’s great teller of stories Sir Walter Scott lived and wrote his best-selling novels, Overlangshaw Farm in Galashiels churns its own creamy milk and free range farm eggs into luxury ice-cream in seasonal flavours such as baked apple, plum, blackcurrant and cranachan in autumn, and bramble, gooseberry and rhubarb sorbet. This local ice-cream’s perfect partner is surely the Border Meringue from Kelso, of which a million are hand-made every year, using organic eggs and sugar.

The Tweed flood plain, known as The Merse, is blessed with fertile alluvial soils for growing wheat, oats and barley, which have sustained Hogarth’s Mill in Kelso for 100 years. In the Cheviot Hills flanking the Tweed to the south, Playfair Farms rear native Cheviot lamb and pedigree Aberdeen Angus and Shorthorn beef, while the Lammermuir Hills to the north are home to Reiver Country Farm Foods’ Blackface ewes and Simmenthal cows. Kezie in Duns is a taste of the Borders at its wildest, selling pheasant, partridge, mallard, woodpigeon, woodcock, venison, rabbit and hare – and indeed of the world at its wildest too, with ostrich, kangaroo, camel and frogs’ legs on sale from their website.

Fishermen pay thousands to cast a line into Kelso’s Junction Pool, where the Tweed meets the Teviot beside the ruins of Scotland’s old capital, Roxburgh Castle. Nearby, Teviot Smokery smokes salmon, trout, eel, duck and cheese over smouldering oak chips. George Purves and Ian Bruce are the last two salmon net fishermen, or ‘sweep fishers’, left on the Tweed near Berwick, in an industry that employed 700 men in 1953 when George started, and gave the ancient Berwickshire village of ‘Fishwick’ its name meaning ‘fish trading place’.

Seventy-three-year-old George is the third generation of Purves to fish at the Paxton station, from a family that’s been fishing since the 1700s. Either side of the nine weeks from the 1st July they’re permitted to net salmon by law, George and Ian catch sea trout and sell it to fishmongers DR Collin in Eyemouth. Both the salmon and sea trout caught by George and Ian’s traditional boats and nets – and muscle power – is also smoked and sold at Paxton House, one of Britain’s finest Palladian mansions on the banks of the Tweed, designed by architect John Adam and recently restored as a heritage trust and museum to its full Georgian splendour. And at Berwick, the Tweed meets the sea, which is an entirely different kettle of fish.