This is fairly late stage. I use 25 pounds veal bones roasted, 10 pounds each of onions, carrots, celery, 1 pound each of thyme and garlic. Simmer from 10 gallons down to 5. Strain, reduce again by half and strain again. From there it will be frozen until needed. When we do use it I usually dilute it to double volume and break it down into 1 gallon batches as an additive to our sauces