Maksym (Kyrgyz grain drink)

Step 1: Toast the 5 ½ oz pearl or hulled barley in a dry heavy frying pan over medium heat, stirring constantly, for 10–12 minutes until deep golden brown and smelling of coffee and toast. Cool, then grind to a fine flour in a spice or coffee grinder.

Step 2: In the same pan heat 1 tbsp sunflower oil over medium-low heat, add 2 ⅛ oz plain wheat flour and fry, stirring, for 5–6 minutes until it is light brown and smells nutty.

Step 3: Whisk the barley flour and fried flour into the cold 10 ½ cups water in a large pot until there are no lumps.

Step 4: Bring slowly to the boil over medium heat, whisking often so it doesn't catch, then simmer on low for 45 minutes, stirring now and then, until it thickens to the consistency of thin cream.

Step 5: Take off the heat and leave to cool, stirring now and again, until it feels just warm on your wrist, about 86°F. This can take 1–2 hours; a cold-water sink bath speeds it up.

Step 6: Stir in the 1 starter: 200 ml of an earlier batch of maksym, or 2 tbsp active rye sourdough starter, pour into a large clean glass or food-grade plastic container, cover with a cloth or a loose lid and leave at warm room temperature (24–82°F) for 8–12 hours, until fine bubbles rise, a foamy layer forms and it smells pleasantly sour.

Step 7: Stir in 1 ½ tsp salt, taste, then pour into clean jugs or plastic bottles leaving 5 cm headspace. Chill for at least 2 hours. If you use sealed bottles, open them once a day to release pressure (a plastic bottle that feels rock-hard needs burping).

Step 8: Shake or stir before pouring, as the grain settles, and serve very cold. Keeps 3–4 days in the fridge; it gets sourer and slightly more alcoholic each day. Throw it away if fuzzy or coloured mould appears, it turns slimy or it smells putrid rather than sour.