How can I keep hot food hot when transporting it, e.g. to a friend's house or a potluck? I usually just give up and take cold food, but I'd like to have more options.
Depending on what it is I am transporting I use different methods, and I use the same methods for both hot and cold transport.
The easiest is the towels in a box; lay four towels down in a shallow box, hanging the other ends of the towels out each side of the box, then put your dish or bread or pot or whatever in the box and fold each of the four towels over the food. If you have hot food, lay some more insulation material over the top, as heat rises. If you have cold food, put the box on the seat, not the floor, as the floor will conduct heat from your vehicle up into your food.
I always have a sleeping bag in my rig and I will sometimes wrap food well with towels and then open the sleeping bag and shove the food into it, wrapping the rest of the sleeping bag over the top if hot food and under the bottom if cold. This has worked a lot for frozen foods when I go bulk shopping in the city, holding food frozen food for 4 hours and more.
I have been able to make a passable insulator using items from around the house:
- Put wadded-up newspaper in the bottom of a cardboard box.
- The next layer is Styrofoam, if you have any (I save leftover packaging).
- Layer on a few kitchen towels.
- Place your covered dish in the box next.
- Finish with more kitchen towels, and get going!
Be sure you have the food coming out of the oven at the time when you're about to walk out the door.
Have your packaging ready, so you're not giving the food time to cool down while you hunt for a box.
I've transported many pies this way, and it's worked great.
Using ceramic cookware provides good thermal mass, and isn't a conductor so won't cool off as quickly as metal will. I just wrap them in two or three bath towels (at least two -- one wrapped in one direction, the other wrapped at 90 degrees, so I don't have a large hole in the end for air to come in).
If you're doing this often enough, or just happen to need the dishes anyway, there are insulated carrying cases sold for various standard casserole dish sizes. But look when you're ordering online -- some come with a dish, lid, insulating bag, and hot & cold packs ... some are just an insulating bag. The hot packs you can either warm up in hot water or a microwave to add extra thermal mass when transporting.
I have two of the Pyrex Portables line that I got when some store was having a good sale, and I also have a slow cooker with clamps to secure the lid, but I don't know that I'd recommend it due what I consider to be a serious design flaw. (and for longer trips, I still wrap the pyrex things in towels, although that means I can't use the carrying handles)
First things first, to keep the food hot you need to take into account two factors: thermal mass and heat conduction.
Thermal mass is how much heat your food or its pot can retain. Generally, heavier pots & pans(cast iron or clay) will be hot for a longer time than thin-walled ones made of steel or aluminum.
Rule of thumb: the heavier the pot, the better its heat retention. Bringing more food also helps!
Heat conduction is how well does a material let heat pass through it. Metals and water give heat away very easily, and aren't good for insulation. Thick fabrics, wool, cotton or just layers of air in between sheets of newspaper are good at keeping heat in.
Rule of thumb: if it'll keep you warm in the winter, it can keep your food warm. My personal favourite is just wrap the pot in a woolen blanket. Just make sure you don't get the blanket greasy!
I transport hot foods in a crockpot with the top held in place with bungy cord(s) or heavy rubber bands or knotted lengths of elastic. What I use depends on the design of the handles of the crockpot. Using towels, blankets,etc. for insulation is effective. I usually put the wrapped container into a non-flexible plastic laundry basket and put it in the trunk--just in case there is any leakage. Even if there is nowhere to plug the crockpot in at the destination, the food usually stays fairly warm in the ceramic part alone (at indoor temperature).
Wrap bricks in foil (one at a time, not together), place and heat in oven for about 30 minutes at 350 deg. Place on bottom of cardboard box, place a heated up moist towel (in microwave) on top of the hot bricks, securely place your pot on top, making sure you wrap towels around the pot so they don't shift around during transport; place more towels on top (at least about four layers); put a used pillow on top and secure the box if it has a flap, otherwise, the pillow on top should suffice. This way method should keep your potluck dish warm for at least an hour.
Sorry to boast about my crockpot, but I just can't help it. It features a lid that locks down to completely prevent spillage, thermal mass to stay warm for a long time, can plug into any outlet if it needs to be kept in warm mode once there, a thermometer to measure temp of the food inside, and a serving spoon that clips right to the lid. All it all, it's pretty much perfect for potlucks.
from personal experience the best way to keep food warm while on a journey is to get a box put your dish in make sure it's been wrapped in foil then wrap it in a blanket but the most important bit is to make sure there is equal insulation on top and bottom or more on top never less than the bottom because the heat rises rather than falls