To make good stock the starting point is a mirepoix (chopped onion, celery and carrots in 2:1:1 ratio), this gives the depth of flavour to the stock.
To the mirepoix and water add the following:
- Vegetable stocks can have mushrooms, garlic and tomatoes ... a bit of citrus is good too. A basic stock can just be mirepoix as a great basic stock.
- Fish stocks should be made with gelatinous fish, flat fish are great for this, also monkfish, don't bother with salmon or oily fish like mackeral. Trim gills and guts (after the fillets have been taken off), I also use a lot of Squid and scallop frills when I've got plenty from a good dive trip !
- Prawn can be a stock on its own or add a little to fish stock ... be careful as they can be very overpowering.
- Chicken stocks like a bit of citrus, half an orange or lemon, then you can use the raw carcass once you've taken the meat off or the bones from the roast for a darker stock.
- Beef is delicious but takes more work ... roast some marrow bones (cut in half to let the marrow out) for an hour or so as the basis for the stock.
A lot of people like to add spices, particularly bay leaves, I prefer to add these to the meal in the same way as seasoning and keep the stocks just about the main ingredient of the stock.
For making each of the stocks its basically the same, heat in water, sieve and concentrate the flavour by reducing the volume.
Vege and fish bring to boil then keep hot but not boiling or it will turn bitter, it is ready in 30-45 minutes. Chicken and Beef can take a gentle simmer, chicken for 2-4 hours and the beef bones for up to six hours to get all the flavour out. Skim if there is foamy scum on top.
I then cool stocks and even fridge overnight to solidify any fat and scum before sieving and reducing, when sieving don't force the fluid out if you want clear stock. The finer the sieve the better.
Once sieved I think all stocks benefit from reduction, rolling simmer till the flavour is concentrated, vege and fish stocks don't take reduction to strong concentrate so well for me ... plus the smell can get too much ! reduce them by 30% or so. Freeze in portion sizes of about 1 cup.
Chicken and beef stocks are great for reducing right down, 95% of volume ... ie 10" of stock liquor in a pot reduces to 1/2" of fabulous concentrated flavour, it will be a thick jelly when cold. I freeze them in the ice cube bags, one 'cube' per portion as a rule of thumb.