In the Orkney Museum in Kirkwall, in the ‘Merchant Lairds’ gallery, there is a large lump of butter excavated from a bog. Records show that rents and taxes in the Northern Isles were often paid by tenant farmers in butter as well as grain. There is even a skerry in Scapa Flow named the “Barrel of Butter”. The butter was usually poor quality fat known as ‘grease butter’,  intended as a lubricant rather than for eating. The Merchant Lairds of the 17^th and 18^th centuries then sold it abroad, to the German merchants who visited Orkney and Shetland. It was a well-documented trade. Shetlanders also paid part of their rent in butter, storing it during the year until payment was due in early summer.

 ‘Bog butter’, a waxy substance which may be either actual butter or tallow, has been recovered from peat bogs in Ireland and Scotland. It was deliberately buried in wooden containers or wrapped in things like animal skins or bark. This is a good method of preservation, as peat bogs are highly acidic and low in oxygen and so bacterial growth is inhibited. The earliest examples known so far date back thousands of years ago to the early Bronze Age. Bog butter typically does not contain salt, and does contain cattle hairs.

Burying a valuable commodity may have been intended to keep it safe from robbers in unsettled times, or to accumulate enough for a rental payment at a later date, or even to hide it from the landlord. A number of writers suggest that the taste of butter intended for eating is improved by burial in a bog (I do NOT recommend trying this.) Several reports mention bog butter being used for waterproofing, for making candles or cement, for greasing wool, or possibly as ritual offerings.

 I have never so far found a reference to the need to grease the axles of carts in any of the publications which describe the wheeled wooden vehicles used in medieval and early post medieval Europe. Diaries describing the difficulties of travel talk about dreadful tracks, and wheels coming off carriages, but do not mention stopping for the wheels to be greased. Other wooden machinery such as windmills, or windlasses for lifting, where friction would also have been a problem, would probably have needed greasing as well. 

However, from archaeological sources it is known that the use of animal fats to grease the moving parts of wooden vehicles goes back to at least the third millennium BCE. A wheel from a sled belonging to an Egyptian pharaoh, which had been used to transport heavy goods, was found to have been greased with animal fat (tallow). So had some chariot wheels from a later Egyptian tomb. The ancient Greeks used animal fat to lubricate chariot wheels during the Olympic Games. The Romans in the early centuries AD are said to have  done the same and in the early middle ages, it was used to grease the wheels of royal carriages and the lifting gear for castle gates. Other lubricants in antiquity included plant and fish oils. By the 18^th and 19^th centuries CE moving parts were starting to be made of metal and mineral oils took over.

So when you next pile your slice of toast high with cholesterol, or pay the garage bill for lubricating the many moving parts of your car, think of the days when a humble crofter’s wife churned rather nasty butter to pay the rent and keep the wheels going. And if you find a reference to greasing cartwheels with butter in early modern Europe anywhere, please let me know.