I own 2 Pyrex Erlenmeyer flasks, a two liter and a four liter, and use the size that is double my starter size. Three to five hours beforehand, yeast comes out of the fridge to warm up. 100 grams of light DME per liter of water. DME goes in first using paper funnel, then add water to desired fill height. Add 1/4 tsp of yeast nutrient and 1 drop Fermcap-S (critical step!) Bring to a boil, stirring with the handle of a long stainless spoon. Reduce heat but continue boil for 13 minutes, stirring often. Add stir bar and cover with aluminum foil for last 2 minutes of boil. Remove from heat and place in ice bath for 15 to 20 minutes (looking for a temp of 70). Spray yeast package or tube with StarSan, remove foil from flask and carefully add yeast to flask. Swirl gently then place on a stir plate in a 70 degree room. A one liter starter is done in 18 hours. I haven’t tested the time for a 2 liter… I leave mine on the plate for 30 to 40 hours, but this may be overkill (I really need to test that). I refrigerate 2 liter starters and pour off the beer prior to using, will do the same with a 1 liter if I’m not ready to use it immediately.