- Small cooler with lid
- 4 1-qt. Mason jars with lids
- 1 gallon milk
- 4 tbsp. yogurt
- In a large pot, heat milk slowly to 120 degrees F on medium-low heat.
- Pour milk into Mason jars.
- Stir 1 tbsp. yogurt into each jar; put on a lid.
- Place jars in a cooler & cover up to top of jars’ band with 120 degrees F water. (Hot water from faucet will work fine.)
- Leave for 12 hours.