Artificial Refrigeration

It is very easy to take fridges and freezers for granted but before the 1970s most British homes had neither.  People have used natural ice to cool food for centuries, which was fine when it was available.  An important breakthrough was the development of machines that could make ice artificially.  After a lot of experimentation these machines began to be used in industry in the mid-19^th century.  I want to look at two of the many people who contributed to refrigeration technology.

James Harrison who set up the ice-making industry in Australia.

James Harrison (1816-1893) was a Scot who went to Australia to set up a printing press.  Apparently, while he was using ether to clean the blocks of type he noticed that the metal became cold.  He must have had an inventive mind because in the 1850s he filed patents for an ice-making machine and an ether vapor-compression refrigeration system.  Vapor-compression systems work because a refrigerant (in this case ether) is circulated around a series of pipes absorbing heat and then releasing that heat elsewhere.

His invention kick started the ice-making  business but more work was needed before domestic refrigerators became common.  It wasn’t just the unreliable and potentially dangerous nature of the early machines.  The lack of electrical wiring in British homes was a major obstacle. The USA was a bit more advanced in this respect, which is where Mary Engle Pennington(1872–1952) lived.

Dr. Mary Engle Pennington.

Mary worked for the U.S. Department of Agriculture and conducted research on refrigeration.  Not only did she do the research she also explained it to the public, publishing booklets about the correct storage of perishable foods and, in 1923, founding the Household Refrigeration Bureau, which promoted the safe use of domestic refrigeration. Later in her career she was involved in the design and construction of domestic refrigerators and refrigerated warehouses.

Back in Britain electrical fridges were pretty rare until later in the 20^th century. As people gradually replaced larders, cellars and ice-boxes with consistently cold humming white boxes it changed not only how we stored food but also how we shop and what we eat.

Cleaning up the Milk Supply

Last week’s protest by British dairy farmers, and their threat to disrupt supplies during the Olympic Games, made me think about milk.   Specifically about how accustomed we are to having clean milk available all year round.  In Britain we might worry that too much double cream is unhealthy but we can assume that milk, and other dairy products, are safe.

Franz Ritter von Soxhlet, the German chemist who developed pasteurization in the late 19th century.

During the 18^th and 19^th century milk could be a source of illness.   Leaving aside adulteration, the way milk was produced and transported allowed harmful micro-organisms to multiply.  Milk cows were often kept in overcrowded conditions, equipment was not always cleaned properly and the lack of refrigeration made things worse.   Tuberculosis was one of the diseases that could be spread by contaminated milk but the lack of certainty about how the disease spread meant there was plenty of room for disagreement.  Some argued that the milk supply could be cleaned up by good hygiene practices alone.  Others argued that pasteurization of milk was absolutely essential.  There were even voices suggesting that the best solution would be for the government to take over milk production as in this 1899 Fabian Society leaflet.

Of all the people who helped clean up the milk supply the Medical Officers of Health deserve a special mention.  These government officials, who began to be appointed from the mid-19^th century, gathered evidence on a range of public health matters including the milk supply.  They inspected milking parlours, visited dairies, tracked the spread of disease and reported on the cause of deaths in their area.   All of which helped to persuade others of the need for improvements.  Some changes were slow to come.  Franz Ritter von Soxhlet (1848-1926) proposed a way destroying the harmful bugs in milk by heating it, i.e. pasteurization in 1886 but British diary farmers resisted compulsory pasteurization.  It wasn’t until 1949 that it became standard practice across the UK. 

This book by Hannah Velten provides more information about the history of milk.

Booking onto a WEA course

I started writing this blog because I will be teaching a WEA course this autumn about food history in Britain.  It will be running on Thursday mornings in Brookmans Park, Hertfordshire.  And, while blogging is fine, it is more fun to learn with other people.

The WEA in the Eastern Region is moving towards doing things on-line, for example they have recently launched themselves on Facebook and Twitter but, to book a place you still need to contact the local organiser directly.  You can do this by using committee@brookmansparkwea.org.uk .  A bit more information about the course can be found on page 10 of this PDF which is a booklet listing all the courses in Bedfordshire and Hertfordshire for 2012/13.   The course I will be running is called Food Heroes and costs £60 for 10 sessions starting on 25^th September 2012.   I’d love to see you there.