Pistachio Ice Cream: The Recipe, the Nuts, and What the Real Colour Is

Pistachio ice cream should taste faintly savoury and slightly resinous before it tastes sweet, with a long finish that keeps going after the cold has gone. If the first thing that arrives is sugar and the second is almond, what is in the cup is probably almond paste with colour in it, which is the most common substitution in the trade and the hardest one for a customer to challenge.

Pistachio ice cream is the flavour worth using as a test of any cabinet, for three reasons at once. The nut is one of the most expensive in the kitchen, so there is a real financial incentive to cut it. Its natural colour is unappealing enough that there is a cosmetic incentive to fake it. And its flavour is delicate enough that a thin, airy base swamps it completely.

The colour question: why green is a warning

Real pistachio ice cream is a dull, slightly greyish sage, sometimes with a brownish cast from the skins. That is what happens when you grind a nut whose kernel is pale green, whose skin is purple-brown, and mix it into a cream-white base. Bright green is not a sign of more pistachio; it is a sign of colour, of a bought-in industrial base, or of almond doing the volume work.

The one honest exception is a Sicilian Bronte pistachio, which has an unusually vivid kernel and gives a noticeably greener result. Even that is a deep olive rather than a lime. If the colour looks like a highlighter, the colour did not come from a tree.

Which nuts, and how they are treated

Two decisions matter more than the variety. The first is whether the nuts are raw or roasted: light roasting deepens the flavour and pushes it toward the toasted, savoury end, while raw nuts keep more of the fresh, faintly grassy note. Neither is wrong, but a kitchen that roasts is making a choice and a kitchen that has never thought about it is not.

The second is whether the skins go in. Skins bring tannin and colour, which means more depth and a duller shade, and leaving them out gives a cleaner but flatter result. Most good versions include some. Beyond that, the nuts want to be ground to a paste rather than chopped, since the fat has to disperse into the base to carry the flavour, and a scattering of coarser nuts is added at the end for texture rather than taste.

Pistachio gelato and pistachio ice cream

The same nut behaves differently in the two products, and this is the flavour where the difference is easiest to taste. In a dense low-air gelato base, pistachio comes forward and the finish is long. In a lighter, higher-fat, higher-air ice cream, the extra fat coats the tongue and the extra air dilutes the dairy, so the same quantity of nut reads as milder and rounder.

That is not an argument for one over the other, but it does explain why the best pistachio is usually found in a gelateria cabinet. If the nut is the point, density helps. The full mechanism is on the gelato versus ice cream page.

A recipe that works without a machine

For roughly a litre: grind 200 g of shelled pistachios with 50 g of the sugar until it turns to a stiff paste. Warm 500 ml of whole milk with 200 ml of double cream and 120 g of sugar until the sugar dissolves, whisk in the paste, and chill the mixture thoroughly overnight. Churn if there is a machine; if there is not, freeze in a shallow tray and beat it hard with a fork every forty minutes for about three hours.

• Chill before churning, always. A base that goes into the freezer warm forms large ice crystals, and no amount of beating recovers it.
• Salt it. A quarter teaspoon does for the pistachio what it does for caramel: it sharpens the sweetness and lengthens the nut.
• Do not add colour. The recipe will look disappointingly grey and taste more like pistachio than any bright green version ever has.