Editing Erlenmeyer flask (section)

==Uses==
===In chemistry===
[[File:Titration NaOH HCl PP.ogv|thumb|Method of swirling an Erlenmeyer flask during [[titration]]]]

The slanted sides and narrow neck of this flask allow the contents of the flask to be mixed by swirling, without risk of spillage, making them suitable for [[titrations]] by placing it under the [[Burette|buret]] and adding solvent and the indicator in the Erlenmeyer flask.<ref>{{cite web|url=http://www.sciencebuddies.org/science-fair-projects/titration_tutorial.shtml |title= Method of titration |website=www.sciencebuddies.org/ |access-date=2016-07-08}}</ref> Such features similarly make the flask suitable for boiling liquids. Hot vapour condenses on the upper section of the Erlenmeyer flask, reducing [[solvent]] loss. Erlenmeyer flasks' narrow necks can also support [[filter funnel]]s.

The final two attributes of Erlenmeyer flasks make them especially appropriate for [[recrystallization (chemistry)|recrystallization]]. The sample to be purified is heated to a boil, and sufficient solvent is added for complete [[Dissolution (chemistry)|dissolution]].  The receiving flask is filled with a small amount of solvent, and heated to a boil. The hot solution is filtered through a fluted filter paper into the receiving flask. Hot vapors from the boiling solvent keep the filter funnel warm, avoiding the premature [[crystallization]].

Like [[Beaker (glassware)|beakers]], Erlenmeyer flasks are not normally suitable for accurate volumetric measurements. Their stamped volumes are approximate within about 5% accuracy.<ref>{{cite web |url=https://www.dartmouth.edu/~chemlab/techniques/flasks.html |title=Erlenmeyer Flasks and Beakers |website=www.dartmouth.edu |access-date=2016-06-17 |archive-url=https://web.archive.org/web/20160616181106/http://www.dartmouth.edu/~chemlab/techniques/flasks.html |archive-date=2016-06-16 |url-status=dead }}</ref>

===In biology===
[[File:Microcystis 1.jpg|thumb|upright|''[[Microcystis]]'' floating colonies in an Erlenmeyer flask.]]

Erlenmeyer flasks are also used in [[microbiology]] for the preparation of [[microbial culture]]s. Erlenmeyer flasks used in [[cell culture]] are sterilized and may feature vented closures to enhance gas exchange during [[Incubator (culture)|incubation]] and shaking. The use of minimal liquid volumes, typically no more than one fifth of the total flask volume, and baffles molded into the flask's internal surface both serve to maximize gas transfer and promote chaotic mixing when the flasks are orbitally shaken. The oxygen transfer rate in Erlenmeyer flasks depends on the agitation speed, the liquid volume, and the shake-flask design.<ref>Soccol CR, Pandey A, Larroche C (2013). Fermentation Processes Engineering in the Food Industry. CRC Press Taylor & Francis Group, Florida. {{ISBN|978-1439887653}}.</ref> The shaking frequency has the most significant impact on oxygen transfer.<ref>Schiefelbein S, Fröhlich A, John GT, Beutler F, Wittmann C, Becker J (2013): "Oxygen supply in disposable shake-flasks: prediction of oxygen transfer rate, oxygen saturation and maximum cell concentration during aerobic growth". Biotechnology Letters. 35 (8): 1223-30, doi:10.1007/s10529-013-1203-9, {{PMID|23592306}}.</ref>

[[Oxygenase|Oxygenation]] and mixing of liquid cultures further depend on rotation of the liquid "in-phase", meaning the synchronous movement of the liquid with the shaker table. Under certain conditions the shaking process leads to a breakdown of liquid motion – called "out-of-phase phenomenon". This phenomenon has been intensively characterized for shake flask bioreactors. Out-of-phase conditions are associated with a strong decrease in mixing performance, oxygen transfer, and power input. Main factor for out-of-phase operation is the viscosity of the culture medium, but also the vessel diameter, low filling levels and/or a high number of baffles.<ref>Kloeckner W, Diederichs S and Buechs J (2014): "Orbitally Shaken Single-Use Bioreactors". Adv Biochem Eng Biotechnol. 138: 45-60, {{PMID|23604207}}</ref><ref>Buechs J, Maier U, Mildbradt C et al. (2000b): "Power consumption in shaking flasks on rotary shaking machines: II. Nondimensional description of specific power consumption and flow regimes in unbaffled flasks at elevated liquid viscosity". Biotechnol Bioeng. 68(6): 594-601, {{PMID|10799984}}</ref><ref>Buechs J, Lotter S, Mildbradt C (2001b): " Out-of-phase operating conditions, a hitherto unknown phenomenon in shaking bioreactors". Biochem Eng J. 7(2): 135-141, {{PMID|11173302}}</ref>