1,000 Bowls of Manhattan Chowder

This is a formula rather than a set of instructions: a caterer's ingredient list sized for a political outing, with the method assumed. The useful work for a modern cook is understanding the proportions and dividing them down.

• ScaleAs written this is on the order of a thousand bowls, the figure the title itself gives; with no method stated the finished volume can only be guessed at, perhaps 60-odd gallons. Dividing every quantity by 100 gives about ten servings: roughly 30 soft clams, 15 hard clams, three-quarters of a pound of potatoes, half a pound of red onion, half a pound of carrots, a pint of canned tomatoes, and so on.
• Bushels and bagsA bushel of onions is generally reckoned at 50-57 lb and a bushel of carrots at about 50 lb. Potato "bags" varied, 50 lb and 100 lb sacks both being trade standards, so 1 1/2 bags could be anywhere from about 75 to 150 lb, against roughly 50 lb each of onions and carrots.
• Soft clams and hard clamsSoft clams are steamers (long-necks); hard clams are quahogs, and the large chowder size is what is wanted. The two do different jobs: the softs give sweetness and body, the quahogs give the chew and the strong liquor. Both should be steamed open first and their strained liquor used as the base.
• Cracker dustSoda cracker dust is finely crushed soda crackers (saltines), sold as crumbs for exactly this sort of use. It is the thickener, though 12 lb spread through a batch of this size is a modest hand rather than a heavy one.
• Back fat, renderedRendered pork back fat is lard. Ordinary leaf lard works, though diced salt pork fried out in the pot gives a closer flavour and leaves you the cracklings.
• The clams go in lastWith the quantity of vegetables here the pot needs long simmering, but the clams themselves need only a couple of minutes at the end. Chopped clams held at a simmer for any length of time turn to rubber, and the flavour goes into the broth and stays there.
• Sherry and WorcestershireTwo gallons of sherry and two quarts of Worcestershire against a batch this size is a light hand -- on the order of a teaspoon or so of sherry and under half a teaspoon of Worcestershire per bowl. Add both off the heat so the sherry does not cook away.
• Ambiguous quantities"12 boxes thyme" and "1/2 small bag salt" are trade quantities with no fixed modern equivalent; season the reduced batch by taste.
• LemonTwenty-four lemons with their grated zest is a deliberate feature, not a garnish -- it is what keeps a tomato-and-pork chowder of this size from tasting heavy. Keep the zest in proportion when you scale down.