Fluid ounce per minute (fl oz/min)

The fluid ounce per minute is a unit of volumetric flow rate equal to one imperial fluid ounce passing a point every minute. Its symbol is fl oz/min. At 28.413 millilitres to the ounce, a minute at this rate delivers a small glass, which places the unit among the deliberate, controlled flows of food, drink and light industry.

Beverage dispensing is its steadiest employer. A post-mix drinks tower is set so that each nozzle delivers a fixed number of fluid ounces per minute, and the ratio of syrup to carbonated water — commonly one to five — is maintained by matching the two rates. A coffee machine's brew rate, a beer line's pour rate and a juice dispenser's throughput are all quoted this way.

Small dosing and metering pumps in food processing carry the same units. Flavourings, colourings, brines and preservatives are injected into a product stream at so many fluid ounces per minute, and the ratio to the main flow is what determines the finished recipe. A pump that drifts by five per cent changes the taste of every package made that shift.

Cleaning and chemical injection follow the same pattern. A dairy or brewery cleaning system meters detergent and sanitiser into circulating water at a rate in fluid ounces per minute, chosen so that the concentration in the loop matches what the supplier specifies for the temperature and contact time being used.

Laboratory and pilot-plant work in Britain and the Commonwealth still meets the unit in older equipment and older standard methods. Rotameters graduated in fluid ounces per minute remain in service, and a technician reading one must remember whether the scale is imperial or American, since the two ounces differ by four per cent.

For orientation, 60 fluid ounces per minute is one fluid ounce per second, 35 fluid ounces per minute is about a litre per minute, and 160 fluid ounces make an imperial gallon. So a dispenser running at 32 fluid ounces per minute fills a gallon in five minutes exactly.

One fluid ounce per minute equals about 28.41 millilitres per minute, about 0.02841 litres per minute, or about 0.01667 fluid ounces per second.

Fluid ounce per minute conversion table