Experiments with hay box cooking

A hay box is not necessarily a box of hay, though it might be. It's a box to put food in that's so well insulated that hot food will continue cooking with no additional input of heat. Not all types of cooking will work here, only slow cooking, the kind for which my oven has an 'S' setting, and which I use for cooking stews and beans.

Over on Selfsufficientish, Nev had posted an article on making a hay box cooker from an old cool box and some polystyrene. I had an old cool box - it used to have a mini fridge unit in the lid, but that broke in a car accident and we bought another one - so that seemed a good place to start. I'd already replaced the broken fridge unit with bubble wrap, so the lid was as well insulated as the rest of it. I also had various bits of polystyrene lying around. Yes, my house is untidy enough that I can find useful quantities of polystyrene just lying around.

Having found the insulation part, I then needed a cooking pot to actually put the food in. I was planning to try stew, so I'd usually cook this in a pyrex casserole dish (or my lovely Le Creuset dish if I'm making enough for six. Sadly, this doesn't happen very often). The trouble with my pyrex dishes is that whilst I have two dishes and two lids, neither of the lids fit either of the dishes. I have to cover the dish with foil when I'm cooking in the oven, which isn't any good for the hay box (or very eco-friendly in general).

Whilst searching for replacement lids, and wondering whether I shouldn't just give in and buy new dishes complete with new lids, which is what the manufacturers want to sell, I kept seeing picutures of these:

Pyrex dish with plastic lid

Oh yes! I thought, I've got one of those! Actually I've got two, but the smaller one hasn't got a lid. I didn't think of this for a casserole because the lids are no good in the oven (this is why my smaller dish doesn't have a lid), but it would be ideal for the hay box.

With all the pieces collected, I then had to fit them together somehow. Unlike Nev, I did not purchase the appropriate tool for cutting polystyrene and carefully cut the pieces into the right shapes. Oh no, I just cobbled together what I had.

As it happened, I had two pieces that both surrounded the pot and fitted into the cool box pretty well.

Pieces of polystyrene conveniently fitting both pot and box

I then found and cut more bits of polystyrene to fill the gaps, so I'd have a polystyrene base and various bits over the top as well. The last of these was a bag of wood shavings that had come as packaging for bulbs (plants, not lights), that would fit into the awkward shape at the top.

Pot sitting on bits of polystyrene in the box, and more bits to go on top, including a bag of wood shavings.

Again failing to follow Nev's good example, I went straight for cooking, rather than testing this out with water first. I prepared my stew, put it in the box and closed the lid at about 11:30 this morning. Come dinner time... um, that's seven hours later, not eight to twelve as recommended... I opened up the box to see what had happened.

Well, it was still warm. Not hot - I could comfortably take the pot out without oven gloves - but definitely warm. When I checked the food, there had been some cooking going on. The meat and carrots were all cooked through, but you wouldn't say the meat had been stewed. It was still pretty tough. Oops. I hadn't really left enough time to stew it properly after that.

I rescued our dinner as best I could by heating the stew up to boiling again in a pan - I'm not sure it's a good idea to eat meat that's been sitting around all day warm, even if it was in a sealed pot - and put it in the oven on a medium heat while I cooked the potatoes. The meat was still rather chewy.

The hay box experiment wasn't a great success, but I can't say it was a total failure either, as the food did cook, just not very well. I'm guessing the problem was the air gaps in my insulation. I reasoned that since my cool box was better insulated than Nev's to start with, I wouldn't need to be so fussy with the additional insulation. And I was lazy. Also, the food didn't entirely fill the cooking pot, which isn't ideal - that made another air gap, and one right next to the food, there in the pot.

I may give this another go at some point in the future. Who knows, I might even test it before using it next time!