Between the end of Christmas and the new year I've spent some days in Helsinki visiting a friend, Will van Twuijver. While there, we tried out some 'home canning', the process of preparing and conserving foods in cans. I had never encountered this practice before in the Netherlands, seeing that it is apparently more common in countries where hunting and fishing are more common and thus the need for processing and storing these large quantities of food. Such is the case in Finland. My friend started canning as a self-initiated project that is part of the sustainability and design program he joined at the Aalto University. However, it is conceptually also an extension of our mutual side-project around home brewing beer. The interest for that was born not out of a love for artisanship or craft, but out of the interest in accessible, 'low-tech', production of industrial products and the associated do-it-yourself hobby culture. An interest which is also about forming communities around a shared machine or process. So far this has resulted in the Brouwvereniging Rotterdam.
Although the practice of home canning is based on cultures of hunting and homesteading more commonly found in rural areas, it can be also applied to a contemporary urban context. Will had already gestured towards this through organizing a workshop based on canning left over foods the participants brought from home. In the wake of Christmas however, another context presented itself. A context which is comparable to the sudden large amounts of meat that need processing after a hunt: the sudden large amounts of surplus Christmas meat supermarkets need to get rid off. In this context we bought a heavily discounted 5,5kg ham which was quickly approaching its 'sell by date' and destined to be discarded. Another approach would have been to dumpster dive but that would have required more intimate knowledge of waste flows in and around Helsinki.
Will lives in a complex of social housing apartments which interestingly enough also seemed incorporate the idea of forming communities around shared machines. The apartment block he lives in is built around an inner square with shared facilities such as laundry machines, saunas, a playground, activity rooms and an outdoor fireplace.
Using this outdoor fireplace we first seared the ham on all sides over direct charcoal heat. Afterwards we wrapped it in few layers of tin foil and buried it a mixture of hot ash and coal, leaving it a few hours to cook further, flipping it over every so often until the inside reached a temperature of 77°C. Then we took it out and let it sit for half an hour.
After spending the better part of the day doing this, we processed the ham into different kinds of stews, based on ingredients we happened to have around the house. Canned foods have a bad reputation partly because industrially canned goods tend to be suspended in a sugary brine. The foods sit in this liquid for several reasons: First, the sugar and salt mixture help preserve the food, as does the liquid by limiting the amount of air in the can and consequently extending the shelf live of the product. The addition of sugar and salt to processed foods also increases flavour and thus sales. The third reason however -I got an inside to through the process of canning- is that the liquid is necessary to provide mechanical strength. The liquid provides a counter-pressure so that the can doesn't implode when it is vacuum sealed. It is quite common for people, especially those concerned about their salt and sugar intake, to toss that liquid and wash the canned goods afterwards, rendering the liquid a discardable packaging material rather than an ingredient. When thinking of recipes to process the ham, the stew emerged as something one could consider a 'native can recipe', where the presence of the salty liquid could be an integral and enjoyable part of the canned goods rather than a disposable packaging material. In that sense soup might actually be considered the ultimate native can food.
To produce the different stews we actually used the cans themselves as miniature pots, placing them over low direct heat and preparing the stews inside. Once the stews were ready and brought to a quick boil, the ham was added and then a lid was put on the can. Once the lids are placed on the can, it is sealed using a device with metal rollers which in turn first bend the can's edge over the lid and then bend both the can edge and the lid the other way creating a tight mechanical seal. Due to the food inside already being hot and thus having a slightly expanded volume, in the process of cooling, the volume decreases and a vacuum is formed, further sealing the can. After sealing the cans they are then placed into a pressure cooker and boiled for over an hour. Whereas prior heating killed off most bacteria in the process known as pasteurization, boiling the cans in a pressure cooker -where the pressure causes the water to reach temperatures well over 100°C- is required to kill off any potential c. botulinum bacteria. This group of bacteria produces a toxin which causes a severe condition called botulism and is one of the major risks when homecanning foods. The toxin is also known from Botox treatment, in which miniature amounts of the toxin are injected to paralyze facial muscles for extended periods of time.
After leaving it in the pressure cooker for about an hour the canned product is ready. It can then be eaten up to two years after the date of canning, although some online sources claim upwards 25 years. On our cans however, themed 'Last Christmas', we put a eat-before date of 24-12-2017 in memory of George Michael: Last christmas I made you ham, but the very next day, you threw it away. This year we saved it for someone special.
To stay up to date with Will's research into canning and his research into 'communities that can' check out his blog: http://canninginhelsinki.blogspot.com/