31. Sourdough starter takes time to prepare, as described (15). Also, it improves with time and age. Thus, people regularly want to know the best way to have starter ready right after Pesach without concern for chometz she’avar alav haPesach, as it will take time to prepare a starter from scratch with flour ground after Pesach.
32. The best option is to wrap the starter in a marked bag and sell it with a kinyan of money to a non-Jew, who will take it to his house and keep it in his fridge throughout Pesach with the complete understanding that it belongs to him. After Pesach, one can buy the starter back for more money than the non-Jew paid, so that the non-Jew is in full agreement that it is a full-fledged transaction. Although some do not usually want to rely on selling chometz (see Issue 88), that is only when the chometz remains in the Jew’s house and the non-Jew only takes a pile of documents or keys to his house, making it look like a joke. However, when the non-Jew takes the chometz to his house and makes a true kinyan, one can fully rely on it without any concerns.
