Can yogurt be fermented using leftover starter curd?

Question

Is it a good practice to use a bit of leftover curd as a starter for your next batch? Learn how to maintain a healthy yogurt culture at home.

Answer 1

Yes, yogurt can be fermented using leftover starter curd. The starter curd contains live and active cultures that will multiply and ferment the milk, creating a new batch of yogurt.

Detailed Explanation:

Fermenting yogurt using leftover starter curd is a common and effective method. The process relies on the live and active bacteria present in the starter, typically *Lactobacillus bulgaricus* and *Streptococcus thermophilus*. These bacteria consume lactose (milk sugar) and produce lactic acid, which thickens the milk and gives yogurt its characteristic tangy flavor.Here's a step-by-step guide:1. **Prepare the Milk:** Heat milk (cow, goat, or even plant-based alternatives like soy or almond milk, though results may vary) to around 180°F (82°C). This step denatures the milk proteins, resulting in a thicker yogurt. If using ultra-pasteurized milk, this step may not be necessary.2. **Cool the Milk:** Allow the milk to cool down to around 110-115°F (43-46°C). This is the optimal temperature for the bacteria to thrive. You can use a thermometer to ensure accuracy.3. **Add the Starter:** Mix in a few tablespoons of your leftover starter curd per quart of milk. Ensure the starter is well incorporated.4. **Incubate:** Keep the mixture at a consistent temperature of 100-115°F (38-46°C) for 6-12 hours. You can use a yogurt maker, an Instant Pot with a yogurt setting, or a warm oven (turned off).5. **Check for Consistency:** After the incubation period, check the yogurt's consistency. It should be thick and slightly tangy. If it's not thick enough, continue incubating for a few more hours.6. **Refrigerate:** Once the yogurt has reached the desired consistency, refrigerate it for at least 2 hours to stop the fermentation process and allow it to set further.

Pro Tip:

Avoid using starter curd that is old or has been contaminated, as this can lead to inconsistent results or the growth of undesirable bacteria. Ideally, use starter from a batch of yogurt that was recently made and stored properly.