Nutrient broth

At 7:00 a.m. I mixed up 4 g nutrient broth powder with 500 mL distilled water, poured 5 mL per test tube (wishing I had pipettors, but I don't), put on lids (not tightly), and put in the autoclave (about 7:30). I made two per student and about 8 extra for me to use to grow cultures or in case of accidents. I didn't have quite enough screw-top test tubes, so I stoppered the rest with cotton balls and lightly covered them with aluminum foil. I wonder if I should have put the cotton balls in after the autoclave process, but I guess I'll find out soon enough. I started off the semester with a 100g bottle of nutrient broth. I'll be interested to see how long it lasts.