The Saye & Sele Arms pub, located on the B4035 in the village of Broughton three miles from the Banbury town centre, launched the new beer called 'The Lord Saye and Sele, Century Bitter.'
Paul Hawkins-Rowe, who owns and runs the Saye & Sele Arms pub with his partner Gale Issitt, described the new bitter and said: "This is a totally bespoke beer at 3.9 per cent as a, session ale. It is a chestnut ale to suit the weather and time of year."
The new commemorative bitter ale can be picked up with a takeaway meal at the pub.
Lord Saye and Sele celebrated his 100th birthday at Broughton Castle, Banbury, in September. Martin Fiennes recently collected some the bespoke bitter on behalf of his father.
Countless organisations, charities and good causes have been given use of the castle and its grounds for fundraising. And Broughton has become well known as a location for films and TV programmes - most recently the hit series, The Crown.
Known as Nat to family and friends, Nathaniel Fiennes is 21st in a line that started with the first lord in 1447 who fought at Agincourt and was Treasurer of England. The family modernised the house, built in the early 1330s and extended in the 1550s. Broughton Castle remains a prime example of a late medieval mansion, unspoiled by later alterations.
Nathaniel Fiennes went to Eton and started a promising cricket career, captaining the Eton XI and the Public Schools XI in 1939. His son Martin believes he could have had a first class cricket career had the war not intervened. He played for Oxfordshire, the Army and the Rifle Brigade which became the Royal Green Jackets, for whom he played until he was about 60.
With his battalion, Nathaniel saw action in France, Belgium and Holland and into Germany, where he was camped near Belsen concentration camp. He and a fellow officer returned to the camp.
He married Mariette, who he had met on a skiing holiday, in 1958 and the couple had a daughter and four sons. The death in 1968 of their third son, Thomas, aged nearly three, cast a shadow over family life as did the death of their eldest son Richard in 2001, aged 41, after a lifetime suffering from epilepsy.
Daughter Susannah Fiennes is a well-known painter and son Martin - they are twins - now run the castle. The youngest son, William Fiennes, is a successful author.