The best brewers make large yeast starters to get their beer fermenting fast. Large populations of active yeast help ensure flavorful beer free of off flavors. Our 2000ml Erlenmyer Flask is the ideal vessel to make a large yeast starter for 5 gallon lagers & high gravity brews. Because it is made from borosilicate glass you can move it from a boil on your gas stove into a cold water bath for cooling, without the risk of cracking. (We do not recommend the use of an electric element. If this cannot be avoided, we recommend using a larger pot as a hot water bath on the stove.) This means you can do the whole process in one container, keeping it simple & helping to reduce the risk of contamination when transferring from one container to another.