Cafe au Lait

A concentrated drip coffee cut half-and-half with hot milk. The whole thing hinges on brewing at double strength, since the milk that follows will dilute it by half.

• The ratioOne tablespoon of ground coffee per cup, but only half a cup of water per tablespoon: double the usual strength, which is what allows the drink to survive an equal volume of milk.
• "Filtered coffee"The book means a drip pot: grounds in a perforated basket, near-boiling water poured over, the brew falling through into the vessel below. A pour-over cone is the closest modern equivalent.
• Filtering twicePassing the liquid back through the grounds appears in period drip-pot directions. With a modern cone and a fine grind, a single slow pour at double strength does the job; a second pass over spent grounds tends to add bitterness.
• Scalded milkScalding means heating to about 180F, when the surface shimmers and a ring of small bubbles forms at the edge of the pan. It should not boil, which throws a skin and gives a cooked, sulphurous taste. Whole milk gives the body the drink expects.
• GrindFine, but not espresso-fine. In a paper or cloth filter, too fine a grind stalls the drip and stews the bed; aim for the texture of granulated sugar.
• ServingTraditionally the coffee and the hot milk are poured into the cup simultaneously from two pots, which mixes them without stirring. Warm the cups first, since a large volume of liquid at 180F loses heat quickly.
• YieldAs written, each cup takes 1 tablespoon coffee and half a cup of water, producing a little under 4 fl oz of concentrate plus an equal amount of milk. Scale straight up; very small quantities cool too fast.