5000ml flask for making yeast starters. We recommend you tell your
customers to use a 3-5 gallon stainless kettle to heat the flask in. Put
two inches of water in the kettle and then place the full flask inside
the kettle. Safer to heat the flask in this manner, protecting both
brewer and stove. Then whole kettle with flask can be brought to the
sink and cooled while the flask remains inside the kettle.