HAY BOX COOKERS - heirloom crock pot for simple living and sustainability

Simple living, frugality, self sustainable, even survival or post industrial – all of these terms apply to the concept I want to talk about today. I am talking about the HAY BOX. I cannot seem to pin down when it got called that – seems to have acquired the name hay box during pioneer days. But the idea of insulated cooking goes way, way back and is also the basis for the big clay ovens that have been in use, well –forever. What is a hay box? Shockingly, it is a box filled with hay. What does a hay box do? Ah, now there is where interesting things start to happen. You start by getting a pot of water boiling hot, then you place it in the box. With an insulated lid (or more hay) on top, the pot is snuggled into the middle of the box. The hay and dead air space slows the loss of heat and keeps the water hot for a very long time. Think about it, once you get a pot boiling on the stove the only reason you need to keep the burner on is to replace lost energy.  If you can slow that energy loss with insulation, then there is no need to constantly add more.  That’s it I’m afraid. No magic, no convection, no microwave – but also, no more energy other than that used to boil the water.

Now why, outside of historical curiosity, would I want a hay box today? Many reasons occur to me. If you really want to practice simple, sustainable or green living, then this is for you – it reduces energy use by 75 to 90 percent. If you are frugal, the energy savings equal lower bills. If you enjoy the ease and taste of slow cooking, then the hay box delivers. If you just want to have access to a way to prepare food with a minimum of fuel used – say during a hurricane or other disaster, then the hay box is the simplest, most reliable way to stretch your cooking energy. Seriously, for such a primitive idea, it really does find its way into many modern situations.

As you can tell, the use of the hay box is much more exciting that its design. In fact, I think I should more properly call this a cooking theory instead of a particular design. In the old days, the designs were pretty basic – a box filled with insulating straw. But, as we have begun to adapt this technology to modern sustainability issues it has developed a bunch of alternatives ways to utilize the principle and not use hay. I am sure the pioneer switch out their hay every time they spilled something on it and gave the wet hay to the cow. But, today we do not keep a ready supply of hay and we have no animals at hand to recycle the mess. Fear not, imaginative people, including me, have come up with dozens of practical and specific variations that will work to meet any need.

If you want super cheap, we have ways to reuse materials in construction. For example, the outer box can be a cardboard box – or better yet, two – one within the other. In fact the box can be any box you wish to use or reuse. Likewise, the insulating material can be hay, paper, aluminum foil, blankets, bubble wrap, aluminum insulation or packing peanuts – hell; it could even be real peanuts.

If all you want is a simple, temporary hay box – any combination of these elements will work. Now, if you want a more attractive and study hay box –here is my best idea.

1) For your box, start with a standard cooler. The closer to the dimension of the pot you will be using the better. Igloo actually makes one called the cube you can buy it at W--mart for $30. This would be ideal – decent looking, additional insulation, sturdy, and portable. The outer dimensions are 20" by 18".  This will give you room for any pot no wider than 10inches across- assuming for interior wall thickness and at least 2 inches of added insulation on all sides. 

2) Get yourself a quantity of Styrofoam sheets. They need to be at least as wide and deep as the cooler and should be thick – 2 to 3 inches is ideal. They sell this in the big home improvement stores - In the insulation department.

3) Here is where it gets tricky, but it is perfect and so worth the effort. Measure the cooler inside bottom. Use those dimensions to cut out a sheet of Styrofoam that will fit snugly in the bottom of the cooler. Cut and place the first sheet. You need at least 3 inches of foam on the bottom, so if you are suing thin sheets add more solid cutouts until the bottom is 3 or more inches thick.

4) Remember, the sides may incline a little so check you interior dimensions every so often to be sure the cut pieces fit snuggly against the sides of the cooler

5) When the bottom is built up – take a piece you have cut for the next layer and trace the bottom of your pot on it in the center of the sheet. Mark it with a thick magic marker. Trace with the marker held up against the side of the pot. This will give you a little extra – you want the hole to be slightly larger than the pot – anywhere from 1 to 2 inches is good. BTW – you must use a straight pot – any bulges or curved place will make things too complicated. A tiny bulge is ok, if it fits in you inch or two safety margin – but straighter is better.

6) Now cut out the circle you have marked. Cut along the outside edge of the mark, this way you will give yourself a little room for the pot to move in and out easily.

7) Continue to measure and cut out these templates until you have reached within 1 inch of the rim of the pot. Don’t go any higher because you do not want the lid to hang on the foam.

8) To provide extra insulation to the top of the cooler – now a hay box, you can do several things or even combine them,

a. You can cut out 2 or more inches of foam and glue it to the inside of the cooler lid – be sure to make plenty of room on the edges so the lid closes without damaging the foam.

b. You can make a cover for the pot by taking a large plastic bag and filling it with packing peanuts. Seal the bag and place it within an old pillow case. You can snug this down around the top of the pot. Be sure it is bulky enough to use up most of the top space. If the case gets dirty, it can be removed for laundry.

9) Now, you have a hat box cooker that will last for years and can be carried out in public without feeling like an outcast.

Note: If your pot is much bigger than 10 inches across, you might could just place it directly in the cube and leave out additional insulation. In fact, if you are lazy and willing to accept lower efficiency, i see no reason why you could not buy a cooler to match your pot size and be done with it. But make no mistake - the energy efficiency will be lower and thus cooking times will increase - don't be lazy.


Ok, I said do not be lazy; but if even this just seems like too much work, there are still answers.

1) If you will be cooking lesser amounts you can try to use a standard, wide mouth thermos. This will work; I’ve done it with rice. But, it is not as effective, because the smaller mass of food stores up less heat and therefore the insulated cooking is only effective for a shorter time. However, it does work, and you can use any cheap wide mouthed thermos

2) If you want to go uptown, the hay box is experiencing such a revival of fortunes that no less that the Thermos company has introduced an entire line of them. All modern and gleaming stainless steel and plastic. The 4.5 liter version runs from $150 to $200. It can be purchased through Amazon and other outlets. There are also Chinese versions that sell for around $70. Globalization, gee whiz.
I am not saying, this is a must have, but if you want to save money, use slow cooking and practice for a simple life – (whether you ask for it or not), then the hay box is at least worth learning about. The process of insulated cooking has many other benefits.  Less water is needed because less evaporates and with it less flavor is lost. Food is cooked at lower temperatures and therefore less vitamin and micronutrients are lost.

Here are a few simple operating principles. To be sure that bacteria are killed; boil larger things like whole potatoes for 15 minutes, large dry beans for 10. All other smaller things like rice or peas can be boiled for just 5 minutes before being placed in the cooker. Food can be left to cook with no tending needed and no danger of burning, and will stay piping hot for many hours. However, the cooking times will be slower and I think one would have to figure out their own times based on the actual results from their pots and their hay box.

Wow, the more things change, the more they remain the same. Who would think modern homesteads would be using an heirloom cooking technique like the hay box. But no one can deny the savings in energy or the environment. Truthfully, I have never even used slow cookers much, but I am determined to fine tune my own thermos cooker until I can at least prepare rice and dry beans reliably. I would love to hear from anyone who tries or has tried this simple living tip.

PS - This is list of times to boil and then time to leave in the hay box – I don’t remember where I found it – but it should be a guide at least. The time seems about right for rice and beans

food type           boil time      hay box time


rice                   5 min           1-1.5 hours

potatoes           15 min         1-3 hours - size matters

soup                10 min         2-3 hours

green lentils      10 min        3-4 hours

pintos              10 min        3 hours

split peas         10 min        2 hours

polenta              1 min        1 hour

hard squash       5 min        1-2 hours