Double-boiler for cheese making
The double boiler (in terms of cheese making) is just a very large Bain-marie. If you are just experimenting with cheese making for the first time and want to try it before you buy all of the equipment, this is an easy one to improvise.
Use two suitably sized pans that will fit freely inside each other and sit the second pan on a couple of items that are poor conductors of heat. I have used a jam-making saucepan, a large saucepan and odd wooden kitchen tools in this instance. It works perfectly well and the set-up pictured here can easily take 5 litres (a gallon) of milk!
Don't attempt to heat the double-boiler to get to the desired temperature, it's very likely that you will overheat the cheese. Add water at the desired temperature and only use the hob to make very small adjustments to the temperature.
Having used the improvised double-boiler for cheesemaking a number of times now I think it probably has an advantage over some of the smaller commercially available double boilers. Because the jam-making pan can hold more than a gallon of water, it is very easy to keep a constant temperature than with a smaller boiler. This is a very handy trait when trying to keep the cheese at 102 degrees for 45 minutes!