What is an Erlenmeyer Flask?
Erlenmeyer flasks are among the most iconic types of lab glassware. Their distinguishing features are their conical shape and narrow neck. This design gives them the advantage of having a large volume relative to their opening to the outside world.
The benefit of this is to reduce evaporation of stored liquids & limit contamination by bacteria & fungi. For this reason they are popular with chemists & biologists for storing chemicals or preparing algal or microbial cultures.
This advantage extends beyond the realm of science to uses at home or work. They make handy milk or juice holders that allow for spill free pouring & can be readily containers to ensure long shelf life.
Cork, Rubber or Other Stoppers
The prevention of evaporation or contamination is further enhanced by using a stopper with the Erlenmeyer flask. A common question to this effect is which is better, cork or rubber? Rubber will provide a better seal but cork has better esthetic appeal, especially when used with consumables such as juices. Either are effective so it really comes down to personal choice.
For large volume sizes such as 2, 5 & 10 litre, cork or rubber stoppers may not be readily available. As you can see in the picture, cellophane plastic wrap works well. Aluminum foil is particularly popular with biologists, especially when autoclaving (pressure cooking). This allows venting of expanding gases while still maintaining a sterile environment.
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