The sourdough starter was brought to England in 1955 where it has been in constant use at a bakery in Bristol.
Sourdough makers create their breads by using a “starter” — a mixture of flour and water which is left to ferment. A portion of that is then added to fresh flour, warm water and salt, which is kneaded to make the dough. The starter is then replenished with fresh organic rye flour and water to keep it going for future doughs.
Some bakers simply replenish the same starter repeatedly, essentially using the same batch for years.
And at Hobbs House Bakery in Bristol, a party has been held for a batch which has been in use since 1955.
Staff have lovingly labeled the mixture as the company's "hardest working employee" — and some think it could be even older than 65. The starter was a gift from another baker who traveled from Germany and settled in England after World War II.
This means it may have been used by generations before arriving in Britain, although the bakery only dates it from when it landed in their hands.
It has been nurtured and cared for daily ever since, and each day some is taken out to bake new breads.
"We like to call our sourdough starter the hardest working employee in the bakery, such an important member of staff deserves a fitting celebration for her birthday each June," said Alice Drake, of Hobbs House Bakery.
"We love to share our family recipes, equipment and ingredients; baker to baker, especially our sourdough starter."
"Over the last few weeks it has been great to see such a huge increase in demand for sourdough baking, we have shipped many hundreds of jars of our sourdough starter across the country to budding home bakers. We love the thought that many thousands of loaves have been enjoyed up and down the country all baked with our edible heritage, to become a custodian of this is priceless."