Ingredients
Soured milk
- 1.5 litreswhole milk
- 3 tbspbuttermilk or live cultured milk, as starter
To serve
- boiled new potatoes with butter and dill
- pickled or fried herring
- salt
Directions
- Warm the milk to 22°C (72°F) — barely warm to the touch. Rūgušpiens is set by a mesophilic culture that works at room temperature, and yoghurt heat kills it.
- Stir in the starter until evenly mixed.
- Pour into a jug or a jar, cover with a cloth rather than a lid so gas can escape, and leave at room temperature for 24 to 36 hours.
- It is ready when it has set softly and tastes cleanly sour — thick enough to coat a spoon but still pourable. It is drunk, not spooned, so do not wait for a firm yoghurt set.
- Chill for at least four hours. It thickens a little more in the cold.
- Serve cold in a glass or a bowl alongside hot boiled new potatoes with butter and dill, and herring. The contrast of cold sour milk against hot buttery potato is the whole meal.
- Keep three spoonfuls back to start the next batch — it will run indefinitely.
Technique
- Room temperature, not warm. This is what gives the mild clean sourness rather than a yoghurt tang.
- Cover with cloth. A sealed lid traps gas and the milk separates unevenly.
- Traditionally this was simply raw milk left to sour on its own. With pasteurised shop milk a starter is not optional, because the organisms that would have done it are no longer there.
Substitutions
- Crème fraîche or live sour cream as a starter, both mesophilic.
- Live plain yoghurt at a stretch, though it gives a sharper result.
Variations
- The Estonian hapupiim, Finnish piimä and Swedish filmjölk are the same drink.
- Drained through muslin it becomes biezpiens.
History
A Latvian summer staple made by leaving raw milk to sour at room temperature.
Frequently asked questions
What is Rūgušpiens?
Rūgušpiens is a cheese & dairy from Latvia: naturally soured milk drunk cold with boiled potatoes and herring. A Latvian summer staple made by leaving raw milk to sour at room temperature.
How long does Rūgušpiens take to make?
Rūgušpiens takes 10 min plus 24 to 36 hours souring of preparation and no cooking at all. The recipe makes makes 1.5 litres. It is rated easy to make.
What can I substitute in Rūgušpiens?
Yes, within limits. Crème fraîche or live sour cream as a starter, both mesophilic. Live plain yoghurt at a stretch, though it gives a sharper result.
What is the most important thing to get right in Rūgušpiens?
Pour into a jug or a jar, cover with a cloth rather than a lid so gas can escape, and leave at room temperature for 24 to 36 hours.
