The 5000 ml Erlenmeyer Flask is the ideal vessel to make a large yeast starter for 10+ gallon lagers and high gravity brews. 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. 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. (Not recommended to use with an electric element.) This means you can do the whole process in one container, keeping it simple and helping to reduce the risk of contamination when transferring from one container to another.