Refrigerate leftover rolls and sauce separately in covered, shallow containers within 2 hours, or within 1 hour if the temperature is above 32°C (90°F). Keep at 4°C (40°F) or below and eat within 3–4 days. If the kefir cheese has a shorter storage limit, follow that limit and count any time it was stored before making the sauce. Reheat the rolls to a centre temperature of 74°C (165°F) and bring the broth to a boil. Add the chilled sauce at serving.