TO REHYDRATE: Mix 5 grams of dried starter and 20 grams of water in a jar. Let it sit covered for at least 30 minutes or longer to let the starter dissolve. Sometimes the bigger chunks won't completely dissolve, and that is totally fine. Add 20 grams of unbleached flour and stir until combined. Cover (not airtight) and leave for 24 hours in a warm spot on the counter. Ideally between 77-85F. It most likely is not going to have any activity. Discard all but 10 grams of starter and feed it 20 grams each of flour and water. Cover and repeat the process every 24 hours until the starter is doubling in size and bubbling. This may take about a week or so.