Rūgpienis

Ingredients

Soured milk

• 1.5 litreswhole milk
• 3 tbspbuttermilk or live cultured milk, as starter

To serve

• hot boiled new potatoes with butter and dill
• fresh curd cheese
• spring onions and salt

Directions

1. Warm the milk to 22°C (72°F) — barely warm to the touch. Rūgpienis is set by a mesophilic culture that works at room temperature, and yoghurt heat kills it outright.
2. Stir in the starter until evenly mixed.
3. Pour into a jug or a jar, cover with a cloth rather than a lid, and leave at room temperature for 24 to 36 hours.
4. It is ready when it has set softly and tastes cleanly sour. It should still pour — this is a drink, not a set yoghurt, and if yours has gone firm it went too long or too warm.
5. Chill for at least four hours.
6. Serve very cold alongside hot boiled new potatoes with butter and dill, with fresh curd and spring onions. The contrast of cold sour milk against hot buttery potato is the entire summer meal.
7. Keep three spoonfuls back to start the next batch — it will run indefinitely.

Technique

• Room temperature, not warm. This is the difference between rūgpienis and yoghurt.
• Cover with cloth; a sealed lid traps gas and the milk separates.
• Traditionally raw milk was simply left to sour. With pasteurised shop milk a starter is essential, because the organisms that would have done it are gone.

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 Latvian rūgušpiens, Estonian hapupiim and Finnish piimä are the same drink.
• Drained through muslin it becomes fresh curd cheese.

History

A Lithuanian farm drink and the classic partner to new potatoes and fresh curd.

Frequently asked questions

What is Rūgpienis?

Rūgpienis is a cheese & dairy from Lithuania: naturally soured milk poured over hot boiled potatoes in summer. A Lithuanian farm drink and the classic partner to new potatoes and fresh curd.

How long does Rūgpienis take to make?

Rūgpienis 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 Rūgpienis?

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 Rūgpienis?

Pour into a jug or a jar, cover with a cloth rather than a lid, and leave at room temperature for 24 to 36 hours.