Why is my sour cream lumpy?

- Culturing at too high of a temperature. Sour cream cultures best between 72-77°F (22-25°C). If the temperature is too high, the culture will grow too quickly and produce too much acid, which can cause the sour cream to curdle and become lumpy.

- Not using a thick enough cream. Sour cream should be made with at least 20% fat content. If the cream is too thin, it will not thicken properly and will be more likely to curdle.

- Over-culturing. Sour cream should be cultured for no more than 24 hours. If it is cultured for too long, it will become too acidic and may curdle.

- Adding too much salt. Salt can inhibit the growth of the culture, which can cause the sour cream to curdle.

- Using a metal container. Metal can react with the acid in sour cream and cause it to curdle.

- Not stirring the sour cream while culturing. Stirring the sour cream while culturing helps to distribute the culture evenly and prevent it from settling at the bottom of the container, which can cause the sour cream to curdle.

- Using a contaminated spoon or container. If the spoon or container used to culture sour cream is contaminated with bacteria, it can cause the sour cream to curdle.