Apr 20 2013

Ice chests, ice houses, strawboxes, streams, springhouses and evaporative cooling. And coolers too.

Ice chests were great things. But they were kind of a rich man’s (or wive’s) convenience. Ice, formerly being a strictly seasonal type of product, was wickedly expensive in summer and it’s harvesting was time and labor intensive. What we used to do was wait for a lake or pond to freeze, walk on out to the middle, drill a hole and begin cutting with saws that looked very much like one-man buck-saws with smaller teeth. Ice was sawn into blocks, loaded onto sleds and drawn for storage in ice houses. If you see old buck saws and ice saws at garage sales, buy them and stop calling them antiques. They really come in handy.

Now the ice houses, big surprise, were often a lot like very large root cellars, there are examples of them being located in caves, but they were often basically barn-like structures. The one thing you were sure to find around ice houses was huge amounts of straw. Above-ground structures required lots more straw. You can store ice under straw right on the ground in straw until spring when you can move it into your root cellar. Packing straw thick and tight on all sides of the ice did so well that New Englanders started shipping it all over the world! And this was with wind-driven craft, sailing ships. Ice was an international industry until refrigeration came along. Imagine being the lucky guy that got to work in the ice house all summer back then eh? Nobody wanted to hear how bad your day was.

Now straw is a really awesome insulator having high mass and low density. Ice houses were packed with it, the ice was packed in it and shipped in it. An ice-box isn’t that well insultated but it wasn’t your only cooling mechanism. Strawboxes are the intermediary. Strawboxes are really big boxes made of wood with drain holes on the bottom and you put down a good foot of straw in the bottom and lay your block ice in nice and tight and put a foot of straw on the sides and on top of the ice. It usually has a lid that hinges down shut on top. The thickness of straw here is arbitraty, the more straw, the more insulation.

So this is where the root cellar can hit the next level. A really cool root cellar can have a massive strawbox in it, there’s ice in it and things we want to keep extra cool stay in there. We’ll use the ice to preserve cooler temperatures in summer as needed or to chip away at for cocktails or to make ice cream in late summer if our stocks hold up well. You want to have some sort of provision for melting water for this.

Now here we go with the hybrids. Don’t worry about finding an icebox at the thrift store, modern coolers work better and that’s your daily household ice supply which you take from the strawbox in the cellar.

A final tip on straw boxes, they are good for more than just cooling. Insulation is pretty indifferent about what temperature it’s maintaining. It keeps in heat too. So let’s say you only have a bit of cook fuel and a big pot of rice. Make your fire, boil your rice as much as you can, when the flame dies, transfer the covered pot to a strawbox, cover it over and wait. Be patient. Let it go about twice as long to check on it and I’ll bet your rice will be done enough. Yup, you knew horses ate straw but you didn’t know straw was so helpful to you eating did you? Try the same trick in a thermos for dehydrated or freeze-dried food, it’s a great field-technique.

The refrigerator-icebox

Don’t worry poor man, I’m always on your side too. Grab a fridge, strip off all the cooling gear (you don’t want chemicals in the ground and around your food), drill some holes into the back for drainage and sink it right into the ground where there’s some shade. Used refrigerators come in handy for all kinds of things. The big thing about using a fridge as an ice box is that you want it on it’s back with the door on top so you are reaching down into it. Cold naturally sinks, and when you open a strawbox or cooler, you access it from the top so all your cold air doesn’t just literally spill down onto the floor.

Evaporative cooling and food storage.

Like many of our environmental factors, evaporative capability is a regional thing. It only works in dry environments, low humidity environments. However, evaporative coolers or “swamp coolers” are used to great effect here in the desert where they do the job of air conditioners at a fraction of the operational cost. I don’t know anybody who’s doing it but there’s little reason not to try it to help root cellars stay cool in hot summers. They do introduce moisture into the air, but air dry enough to benefit from evaporative cooling is dry enough to tolerate some moisture as I mention elsewhere here. Evaporative
cooling can be used in a humbler capacity. We have these butter boxes, a sort of open wooden cube that wet cloths are draped over and you put a stick of butter down in the middle and the evaporative action will probably keep your butter from melting. How do they work? Well in dry air, water evaporates pretty easy. The air is “thirsty”. But converting that water into vapor is a physical change of state and that requires energy. So simply put, heat is the energy that is expent to turn the liquid water into vapor. The heat comes out of the air. The cooler the water, the more heat energy is exchanged with the air to turn the water into vapor. The result is cool air. Or cooler air. You can generally get 20 F below ambient temp with a swamp cooler, more with a more expensive one.

Obviously our examples like the butter might seem trivial, however this is a short-term tool that might help you save your stash one day. In a dry climate, water can help you control the temperature of the air. I’ve made a “butter box” out of a whole RV that was roasting by hanging wet towels all over the place.

The springhouse and springboxes.

Any cool running stream is a great boon to food storage. An icy spring is truly a miraculous thing. The very first thing we can do is make a “springbox” which is a box with holes in it. Milk crates work just fine. We settle this down in a shady part of the stream (or ideally a nice cold spring) and put cans and jars and bottles of food and milk in it to keep cool. Make sure you weight the bottom of your springbox with rocks and tether them to a nearby sapling, they have a tendency to want to migrate downstream. A slightly evolved version is an actual house or structure built over your springbox. Generally these are low-roofed structures with an earthen, stone or gravel floor and they have only minimum venting to keep their moisture and coolness inside. They tend to be small and have low roofs. Things might be kept right in the springbox such as milk or on shelves such as canned goods.

Sand storage of foods.

OK so we’ve seen how we can create particularly cold parts of our root cellar with straw boxes and ice. We talked about a certain level of humidity being good but some foods like to stay a bit dry while they are staying cool. Root food like potatoes, carrots, parsnips and the like really like being kinda medium-dry. So we as we recall using gravel on the floor to assist drainage and evaporation in a root cellar. Moisture coating the gravel increases it’s surface-volume, exposing more of the water to airflow and thence helping with evaporation which produces cooling. As well as giving your feet something to walk on besides mud. We use the same trick with tubers. This includes potatoes, carrots, beets, sweet potatoes, parsnips and stuff like that. A favorite trick is to store them buried in buckets of clean, dry sand. This increases air flow across the tubers themselves and helps wick moisture away from their surfaces but it doesn’t let them dessicate. Keep an inch or two layer of sand between it’s neighbors and the sides of the bucket. Now put the buckets higher up in the cellar where it’s likely to be just a bit warmer. This will tend to keep them dryer and will keep old mold at bay. That’s “dry storage” they only teach in the mountains.

Hanging and stacking foods in storage.

Herbs, plants and flowers do fine hanging upside down in storage. Dried flowers and herbs maintain much of their flavor in oils, and by not breaking down or chopping them, we preserve these oils in the freshest state we can so they are “virtuous”. We generally want herbs and flowers to dry slowly and the cellars can be good places to start, and we start them up high where our temperature is higher and the moisture is lower. Other oily things such as cheeses and hams tend to do well hanging because their oils will tend to bleed out onto whatever surface they are sitting on. Hanging these types of food in storage eliminates all the issues of cross-contamination with surfaces. Be aware that hams and cheeses (and other things) can sweat and drip on whatever is below them so you don’t want much of anything below them. Some people say to stack your apples high and close to vents. The explanation goes that apples and fuits will emit chemicals as they ripen which can trigger other vegetables and fuits in storage to spoil faster.