Gaz — Isfahan's pistachio and rose-water nougat

i. Origin & history

The name comes from gaz-angebin (gaz-angabin), a sweet, sticky substance found on a thorny wild shrub of the genus Astragalus, known locally as gavan, that grows in the Zagros mountains west of Isfahan. The manna is produced when small insects feed on the plant's sap and leave sugary secretions, which harden in the dry air. It was gathered by hand in late summer, cleaned and boiled, and its sweet, slightly herbal flavour made it a prized sweetener. It is sometimes described as tamarisk manna, but the manna used for gaz comes from the Astragalus shrub.

Isfahan's confectioners turned this manna into nougat by beating it with egg whites and nuts, and gaz has been the city's signature sweet for centuries. The town of Khansar, in the mountains where the shrub grows, is also known for its gaz. Today, gaz-angebin is scarce and expensive, and most gaz is made with sugar and glucose syrup, sometimes with a little real manna added for flavour. Gaz labelled as containing a high percentage of angebin is sold at premium prices.

Gaz is a fixture of Nowruz, the Persian New Year, when it is set out for guests alongside other sweets, nuts and dried fruit. Boxes of gaz, in tins or round cardboard boxes printed with the turquoise domes of Isfahan, are the classic souvenir from the city and a standard gift for visitors. It is eaten with tea throughout the year.

Gaz belongs to the large family of nougats made from whipped egg whites, sugar or honey, and nuts, found from the Mediterranean to Central Asia: Italian torrone, Spanish turrón, French nougat de Montélimar and Turkish koz helva. Gaz is distinguished by its rose water, its high proportion of pistachios, its soft, chewy texture, and its coating of flour.

ii. How hot syrup turns egg whites into chewy nougat

Gaz is a meringue-based confection. Egg whites are whipped into a foam, and a hot sugar syrup is poured into them in a thin stream while whisking. The heat of the syrup partly cooks the egg proteins, stabilising the foam, while the sugar dissolves into the bubbles' walls, creating a thick, glossy, sticky mass, like an Italian meringue but much denser.

The temperature of the syrup determines the texture of the finished gaz. Syrup cooked to about 125–130 °C (the hard-ball stage) produces a soft, chewy nougat that holds its shape. A cooler syrup gives a soft, sticky gaz that spreads; a hotter one, cooked towards the crack stage, makes a hard, brittle nougat like some Italian torrone. Glucose syrup or honey is added to the sugar to prevent crystallisation and keep the nougat chewy.

After the syrup is added, the mixture is beaten for some time, often over gentle heat in a bain-marie, to drive off more moisture and make it firm enough to shape. Traditional confectioners in Isfahan beat it for a long time in large copper pans, with heavy paddles.

Finally, the nuts and rose water are folded in, and small rounds are shaped and dusted with flour, which stops them sticking to each other and to the packaging. The flour coating is characteristic of Isfahan gaz.

iii. Ingredients

Makes 30 servings · scroll the side panel to adjust

• 300 g sugar
• 150 g liquid glucose or light honey
• 80 ml water
• 2 large egg whites, at room temperature
• 1 pinch salt
• 2 tbsp rose water
• 10 saffron threads, ground and steeped in 1 tsp hot water (optional)
• 250 g whole shelled pistachios (or blanched almonds)
• 60 g plain flour, for dusting

Use whole, unsalted pistachios, ideally Iranian, slivered or whole; blanched almonds are a cheaper and also traditional alternative. Liquid glucose gives the most reliable chewy texture; honey adds flavour but makes the gaz softer and darker. Real gaz-angebin is sold in some Iranian shops and can replace some of the glucose for an authentic flavour. Use culinary rose water; Iranian brands from Kashan are strong and fragrant. A sugar thermometer is essential.

iv. Method

1. Spread half the flour on a tray. Toast the pistachios lightly in a dry pan for 2 minutes, then keep them warm in a low oven, so they do not chill the nougat when added.
2. In a heavy pan, combine the sugar, glucose and water. Heat gently, stirring until the sugar dissolves, then boil without stirring.
3. When the syrup reaches about 115 °C, start whisking the egg whites with the salt in a stand mixer until they hold stiff peaks.
4. When the syrup reaches 125–130 °C, take it off the heat. With the mixer running, pour it in a thin, steady stream onto the egg whites, avoiding the whisk.
5. Keep beating for 8–10 minutes, until the mixture is thick, glossy and stiff, and has cooled slightly. Beat in the rose water and saffron.
6. Fold in the warm pistachios with a greased spatula until evenly distributed.
7. With greased hands, take walnut-sized pieces of the nougat, roll them into balls and flatten them into rounds about 4 cm across, placing them on the floured tray. Dust the tops with the remaining flour.
8. Leave to firm at room temperature for at least 6 hours, or overnight, before storing.

v. Tips & common mistakes

• Use a sugar thermometer. The syrup temperature decides whether gaz is soft, chewy or hard.
• Pour the syrup slowly. Poured too fast, it cooks the whites into lumps; poured onto the whisk, it splatters and forms threads.
• Beat long enough. Under-beaten nougat is too soft to shape and spreads on the tray.
• Warm the nuts. Cold nuts make the nougat seize before it can be shaped.
• Grease your hands and tools. Nougat is extremely sticky; ghee or a neutral oil makes it manageable.
• Store away from humidity. Nougat absorbs moisture from the air and becomes sticky.

vi. Variations

Pistachio gaz is the classic; almond gaz is a cheaper everyday version. Saffron gaz is golden and fragrant. Angebin gaz is made with a high proportion of genuine manna and is the most prized. Gaz is sold both as round pieces and as small, bite-sized cut pieces, plain or with a flour coating. Some confectioners make gaz with cardamom or chocolate.

Related Persian sweets include the saffron ice cream bastani, the fine sugar floss pashmak and the saffron rice pudding sholeh zard. For similar nougats and confections, compare Turkish delight (lokum), and for other egg-white-based sweets, the French macarons and meringue kisses.

vii. Serving & storage

Gaz is served at room temperature, with black tea, on its own or as part of a platter of sweets at Nowruz and when guests visit. Shake off excess flour before eating, if you wish.

Store it in an airtight tin, with layers separated by baking parchment, in a cool, dry place. It keeps for about three weeks, becoming slightly firmer over time. Do not refrigerate it, as humidity makes it sticky. Gaz can be frozen, well wrapped, for up to three months.

ix. More from Persian

• Pashmak — Persian sugar floss
• Bastani — saffron and rose ice cream
• Sholeh Zard — saffron rice pudding
• Pistachio Rosewater Cake — Persian-style cake
• Turkish Delight — rose lokum
• Chak-Chak — Tatar honey-fried dough