If you make your own stocks from scratch you can save more than just money. It IS possible to bottle these in the Fowler’s Vacola Preserving systems (pouring your stock into those clip jars, then sterilizing them in the boiling vat) but that requires dedication. Easier to pour the stock into your recycled plastic containers (Tupperware, Nylex, Rubbermaid etc. or Pyrex lidded bowls) or failing this, into plastic bags sitting in bowls and remove from the bowls when they are well frozen.
Anyway, I am sure you now how easy freezing is. Label them well too. Especially if you are making fish stocks.
Chicken stock – I stockpile (hah, that must be the origin of the word) chicken carcasses or alternatively, get a bag or two of bones from the Vietnamese butcher who is very generous. Either free with my meat order or $1 a bag without other purchases, Cheeeeap! When I have a mountain of bones and the day before rubbish day (especially in summer you don’t want these hanging around), I cook them up with the usual stuff – celery, carrots, garlic, bouquet garni (the latter really being a heap of herbs out of the garden that I crush up and stuff into a large tea ball and hook over the side of the pot for easy removal), star anise, ginger chunks, a bit of salt & pepper, a birdseye chili. Boil for around 30 mins. Too much boiling and you will make it bitter. Remove the bouquet garni then cook 10 minutes more. Strain when cool. Any fat can be skimmed off after it is completely cold or after freezing and when you are about to use it.
Beef stock – This needs a nice collection of shins and ribs from your friendly butcher. Same ingredients as above but not the star anise. Add a little vegemite for a nice colour.
Seafood stock/fish stock – Save your leftover crayfish shells and prawn shells in the freezer till you have enough. Same ingredients as above Chicken Stock but add some lemon juice and some dill. Strain well and freeze in small portions as this is extremely strong.
Lamb Stock – as above but use mint and lemon and more garlic. For extra taste, boil a lamb shank in with the stock and take it out after an hour or a bit more when it is sticky and glutinous. Great in winter for a snack!
In terms of carbon savings, you always save by bulk cooking. You are doing without the wasteful packaging. You can use your own herbs. Saving also all the transport costs of the commercial product and of course, you are NOT adding anything artificial. Yes, you may freeze this but the cost of running a chest freezer is minimal and if you have solar power it may be nil!
Besides, it is a very therapeutic exercise and the winter soup ritual is quite an exciting, creative (and cost effective) one.