Lemon Sherbet

A milk sherbet rather than a water ice, and the sequence of steps is the whole trick. Everything hangs on when the lemon juice goes in.

• Add the juice lateLemon juice poured into liquid milk curdles it on contact. The recipe waits until the mix is partly frozen and thick precisely so the acid is diluted through a semi-solid mass; the curd still forms but stays fine enough to read as texture rather than lumps. Do not shortcut this.
• "Freezer" means the churnIn books of this period a freezer is a hand-crank bucket churn packed with crushed ice and rock salt; proportions commonly given run to around three parts ice to one part salt by volume. A modern electric ice cream machine works the same way; a frozen-bowl machine will handle this quantity only in two batches.
• Sugar by weight1 1/2 pounds of granulated sugar is about 3 1/3 cups. That is a high proportion, which is deliberate in an uncooked dairy ice: sugar keeps it from freezing to a solid block.
• Lemons then and nowFruit size and yield varied, so six lemons will not give a fixed quantity. Six modern lemons give roughly a cup and a half of juice; start with less, taste the mix before churning, and remember that cold mutes sweetness.
• Strain the juicePips and pulp will not break down and become gritty specks in the finished sherbet. Strain through a sieve before adding.
• The orange variationGrated rind carries the aromatic oils, so zest the oranges before juicing them. The recipe does not say when to add them; adding rind and juice along with the lemon juice follows the same logic as the lemon.
• Yield and holdingTwo quarts of milk plus sugar makes about 2 1/2 quarts finished, serving twelve to fourteen. With no eggs or cream it hardens fast in a modern freezer; move it to the refrigerator for 15 minutes before scooping.
• Milk, not skimWhole milk is the intended article. Reduced-fat milk gives a thin, icy result with a coarser crystal.