Waste Not, Want Not: Physics and Fruitcakes

By Simon Werrett

In 1767, the Winchester writer Ann Shackleford gave a recipe for clear fruit cakes in her Modern Art of Cookery Improved (1767). A candied fruit juice should be placed ‘upon glass plates, or pieces of glass’ and dried in a stove or oven, ‘or by setting them in a window where the sun comes, keeping the window shut’.  In 1666 Isaac Newton bought a triangular glass prism and after darkening his room, he let in a beam of light through the window shutters and passed it through the prism. This created a spectrum of colours, and when Newton passed one coloured beam through another prism, with no change, he concluded that white light was made up of a series of fundamental colours.

Newton’s scientific experiment. Light dispersing through a triangular prism. Image credit: D-Kuru/Wikimedia Commons.

What is the difference between these two performances? In one sense the answer is quite obvious – one is a cookery recipe, and the other is a famous scientific experiment. One is not very interesting – unless you like fruitcakes – and the other is a profound moment of human discovery. As Alexander Pope famously wrote, ‘Nature and Nature’s laws lay hid in night: God said, Let Newton be! and all was light’. But there are many similarities. Both happened at home – Shackleford’s recipe would presumably be done in a kitchen and Newton did his experiment at home in Woolsthorpe Manor, Lincolnshire, and in Trinity College, Cambridge. Both made use of glass items that were ready to hand (prisms were a toy and Shackleford was probably using pieces of old bottles or glasses). Both used a window to manage light, either in terms of generating a beam of light or to dry out the fruitcakes. Both Newton and Shackleford wrote accounts of these events so that someone else could repeat them.

In fact recent research by historians is revealing how early modern householders might not have viewed these two episodes as differently as we do today. People in the seventeenth and eighteenth centuries viewed both Newton and Shackleford’s activities as ‘experiments’. Experimenting was something expected at this time of all good householders. Books of advice on ‘oeconomy’, or household management, encouraged ‘thrift’, which meant not so much saving money as finding a balance between buying new and making good use of the things one already possessed. Thrifty householders should make a point of finding out new uses for things and looking after them to ensure they could be useful for as long as possible. So men and women recorded recipes for cooking, cleaning, gardening, and making medicines which might be carried out by all the family. Contemporaries called this an experimental enterprise, because it involved trying out recipes, testing cleaning methods, trialling medicaments, and figuring out what you could do with old and broken possessions. In 1662, for example, the writer on oeconomy Hannah Woolley published a recipe book called The Ladies Directory, in Choice Experiments & Curiosities of Preserving in Jellies And Candying both Fruit & Flowers. Newton and Shakleford were both householders, and from this perspective of thrifty household management they were both experimenters. They were both finding out new uses for things (prisms, broken glass, light, fruit juice), and they both ‘made use’ of their homes (windows, sunlight) as a kind of experimental apparatus.

Kitchen ‘experiments’. Gerrit Dou, Woman Pouring Water into a Jar (c. 1655). Image credit: Wikimedia Commons.

Of course we don’t remember Newton and Shackleford today as doing the same thing: far from it! Why is that? It seems that in the seventeenth century, some male householders decided to take these family experiments outside the home to new places like universities and academies where they argued that domestic know-how should count as a form of scientific knowledge. Science already took in things like mathematics and astronomy, but it was controversial to say that mundane everyday knowledge of the kind found in household recipe books should count as science. The seventeenth-century chemist Robert Boyle, for example, explored the optics of eggwhite bubbles and experimented with eggs, coriander seeds, distilled liquors, wine, beer, vegetables, jars of oil, and vinegar. Contemporary wags lampooned him for investigating the phosphorescence seen in rotting fish and meat because this wasn’t the sort of thing normally associated with doing science. Nevertheless, over time, men like Boyle divorced elements of domestic knowledge from their original homely settings and ‘experiment’ came to be seen as an exclusively scientific, and male, enterprise.

While most experiments happened at home in the seventeenth century, by the nineteenth this new profession of ‘scientists’ built specialised laboratories and insisted that kitchens, parlours and basements were no longer acceptable as spaces to investigate nature. Today we find it hard to imagine a time when cooking fruitcakes and studying light could be seen as a similar sort of inquiry. But for early moderns, household oeconomy encouraged making use of things to find out what they could do. That could mean exploring light or inventing new recipes for fruitcakes. Recognising this demands a new recipe for the history of science: if we want to understand experimenting, we’ll need to pay more attention to the home as a place where people studied nature, and we’ll need a bit more room for forgotten female writers like Shackleford.

Waste Not, Want Not: An Introduction to Histories of Food Waste, Thrift, and Sustainability.

By Eleanor Barnett and Katrina Moseley

As awareness of global climate and humanitarian issues increases, a growing number of us are seeking ways to grow, buy, and eat food more sustainably – by, for example, using food sharing apps to prevent food waste, reducing our plastic packaging consumption, or switching to less meat-centric diets. In the world today, one-third of the food produced for humans is estimated to go to waste, with society throwing away ten million tonnes of food per year in the UK alone. At the same time, food systems contribute to 37% of greenhouse gas emissions globally. 

But how did societies think about food waste before these concerns earned a regular spot in the headlines? And what might we learn about the past – how people lived day-to-day, their beliefs, and the wider advances in industry – through this focus on food? This month’s thematic series, edited by Eleanor Barnett and Katrina Moseley, explores the history of food waste, thrift, and sustainability from the early modern period to the present. The blog posts are based on a series of papers presented at the ‘Waste Not, Want Not’ conference at the University of Cambridge (September 2019), which brought together historians, sociologists, and industry experts to address these topical questions.

John Gilroy, We Want Your Kitchen Waste (1939-46). Image credit: Wikimedia Commons.

Prior to the invention of artificial refrigeration, consumers themselves had to come up with thrifty ways to preserve food, which would otherwise quickly spoil or rot. Certain papers demonstrate how these kitchen experiments carried out by ordinary people (often women) might best be understood as scientific advancements. Others look at inventions in the packaging industry, from tin cans to plastic film, which have transformed the way that we eat today. ‘Thrifty’ foodways also demand particular attention in the context of conflict and war, when rulers used propaganda to enforce food rationing and new methods of collective cultivation on entire societies.

Moving from methods of preventing food waste to the food waste itself, several posts in this series explore processes that transformed waste products – like molasses from sugar or the ‘skim’ from milk – into viable and even desirable comestibles. The rise of veganism in recent years has seen similar developments, with companies transforming Aquafaba – the liquid gloop at the bottom of a can of chickpeas – into an egg substitute for baking, for instance. On the other hand, changing food habits have had the opposite effect: national consumption of offal (another ‘waste’ product) has declined dramatically in the past fifty years, from more than 50g per person per week in 1974 to only 5g in 2014.

Addressing themes of waste and sustainability in the history of food, these papers have made us think more about the historical relationship between cookery and scientific innovation, about the central role of food in wider social and political power dynamics, and about the enduring relationship between food and identity.

A particularly successful feature of the conference was the conversation it sparked between historians and present-day policy makers. Pioneering initiatives like History and Policy and Cambridge Sustainable Food can use knowledge of past food practices to better understand the advent of present-day food sustainability issues, to inform the direction of food initiatives in the future, and to engage the public with these consequential topics.

In what follows, some of our speakers reflect on the key themes from their papers.


This conference was hosted by Cambridge Body and Food Histories group, co-convened by Lucy Havard, Philippa Carter, and Kylie Chiu Yee Lu, and gratefully funded by Cambridge AHRC-DTP.  For a full list of our fantastic speakers follow this link!