# Consistometer

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{{Short description|Device for measuring the consistency of semi-liquid foodstuffs}}
{{Use dmy dates|date=March 2025}}
{{multiple image
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 | image1 = Bostwick consistometer 01.jpg
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 | caption1 =A Bostwick consistometer from the top, [barbecue sauce](/source/barbecue_sauce) ready to be released and measured
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 | caption2 = A Bostwick consistometer from the top, the release sprung and barbecue sauce flowing
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A '''consistometer''' is a device for measuring the [physical consistency](/source/physical_consistency) of a substance.  It is most often used for foods such as [ketchup](/source/ketchup) and other thick fluids or semi-fluids.  

Consistency is typically measured in terms of rate of flow, as opposed to [viscosity](/source/viscosity) which is measured in regard to force within units like [poise](/source/Poise_(unit)).  Consistometry readings can roughly correspond with viscosity measurements, but some substances such as [carob flour](/source/carob_flour) have little to no effect on consistometer flow but can increase apparent viscosity.<ref name="Mouquet"/>  People's sensory perception of a food seems to track more with the consistency than the viscosity.<ref name="Mouquet"/>  Using a consistometer is also useful on non-homogeneous substances that would give poor readings with a [viscometer](/source/viscometer).<ref name="Mouquet"/>

One of the most common types is the '''Bostwick consistometer''' which was invented by bacteriologist {{ill|Elmer Patton Bostwick|wikidata|Q124351795}} (1893–1958).<ref name="US2295710A">{{cite patent |country=USA |number=US2295710A |inventor=Elmer Patton Bostwick |invent1= |invent2= |status=Expired – Lifetime |title=Consistometer |pubdate= |gdate=1942-09-15 |fdate=1941-12-12 |pridate=1941-12-12 |assign1= |assign2= |url=}}</ref><ref name="mic">{{cite web |title=Microscope |url=https://americanhistory.si.edu/collections/nmah_1348388 |website=National Museum of American History |access-date=9 January 2024 |location=Washington, DC |language=en}}</ref>  This device consists of a rectangular container with two sections:  one of a set volume and the other at a slight decline with centimeter measurements along the bottom.<ref name="US2295710A"/>  Dividing the two sections is a sluice gate that can be sprung quickly open, allowing the substance to flow under its own weight.<ref name="US2295710A"/>  The distance traveled is noted at a specific time, typically thirty seconds, and compared to known samples.<ref name="Mouquet">{{cite journal |last1=Mouquet |first1=Claire |last2=Greffeuille |first2=Valerie |last3=Treche |first3=Serge |title=Characterization of the consistency of gruels consumed by infants in developing countries: assessment of the Bostwick consistometer and comparison with viscosity measurements and sensory perception |journal=International Journal of Food Sciences and Nutrition |date=2006 |volume=57 |issue=7–8 |pages=459–469 |doi=10.1080/09637480600931618 |pmid=17162325 |access-date=14 January 2024 |language=en |url=https://www.tandfonline.com/doi/full/10.1080/09637480600931618 |issn=1465-3478 |oclc=110455362|url-access=subscription }}</ref><ref name="catsup">{{cite web |author1=United States Department of Agriculture Agricultural Marketing Service Fruit and Vegetable Division Processed Products Branch |title=United States Standards for Grades of Tomato Catsup |url=https://www.ams.usda.gov/sites/default/files/media/Tomato_Catsup_Standard%5B1%5D.pdf |website=USDA Agricultural Marketing Service |publisher=USDA |access-date=2 March 2025 |location=Washington, D.C. |language=en |date=27 January 1992}}</ref>  A Bostwick consistometer is relatively easy to use in remote locations without electricity and is much cheaper than a viscometer.<ref name="Mouquet"/>

Tomato ketchup must be measured with a Bostwick consistometer to be [graded](/source/Food_grading) in the United States.<ref name="catsup" />  Grades A and B must be of a "good consistency" and test at 3.0–7.0 centimeters in 30 seconds at 20°C.<ref name="catsup" />  Grade C will have a "fairly good consistency", which is outside the bounds of "good consistency" and flow 2.0–10.0 centimeters in 30 seconds at 20°C.<ref name="catsup" />  Other items, such as [steak sauce](/source/steak_sauce) have similar guidelines.<ref name="Steak">{{cite web |title=COMMERCIAL ITEM DESCRIPTION STEAK SAUCE |url=https://www.ams.usda.gov/sites/default/files/media/CID%20Steak%20Sauce.pdf |website=USDA Agricultural Marketing Service |publisher=U.S. Department of Agriculture |access-date=2 March 2025 |location=Washington, DC |page=3 |language=en |date=3 September 2008 |quote=6.1.5 Consistency. The consistency shall be not less than 6.5 centimeters or not more than 17.5 centimeters in 30 seconds at 20°C (68°F) ± 1°C (1.8°F).}}</ref>

A different type of device is the '''Adams consistometer''', alternately called the '''Grawemeyer and Pfund Consistometer'''.<ref name="Bourne" />  This requires a larger sample than the Bostwick does, of around a half liter as opposed to around 100&nbsp;mL.<ref name="Mouquet"/>  This makes it better for measuring things like [creamed corn](/source/creamed_corn).<ref name="Adams">{{cite journal |last1=Adams |first1=M.C. |last2=Birdsall |first2=E.L. |title=New Consistometer Measures Corn Consistency |journal=Food Industries |date=1946 |volume=18 |issue=6 |pages=78–80, 226, 228 |url=https://archive.org/details/sim_food-engineering_1946-06_18_6/page/78/mode/2up |access-date=8 March 2025 |language=en}}</ref>  It operates similarly to the Bostwick, but the substrate flows over a flat plate and not just in one direction.<ref name="Grawemeyer">{{cite journal |last1=Grawemeyer |first1=Elizabeth A. |last2=Pfund |first2=Marion C. |title=Line-Spread as an Objective Test for Consistency |journal=Journal of Food Science |date=March 1943 |volume=8 |issue=2 |pages=105–108 |doi=10.1111/j.1365-2621.1943.tb16550.x |url=https://ift.onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2621.1943.tb16550.x |access-date=4 March 2025 |language=en |issn=0022-1147 |oclc=5152883494 |archive-date=3 March 2025 |archive-url=https://web.archive.org/web/20250303000340/https://ift.onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2621.1943.tb16550.x |url-status=live |url-access=subscription }}</ref><ref name="Adams" />  The fluid is poured into a cylindrical or slightly conical reservoir centered on a plate, which is lifted to let it flow out.<ref name="Grawemeyer" /><ref name="Adams" />  One advantage over the Bostwick is that measurements are taken in four directions and averaged to yield a more robust result.<ref name="Bourne">{{cite journal |last1=Bourne |first1=M. C. |title=A Classification of Objective Methods for Measuring Texture and Consistency of Foods |journal=Journal of Food Science |date=November 1966 |volume=31 |issue=6 |page=1012 |doi=10.1111/j.1365-2621.1966.tb03285.x |url=https://ift.onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2621.1966.tb03285.x |access-date=4 March 2025 |language=en |issn=1750-3841 |oclc=5152567268 |archive-date=2 March 2025 |archive-url=https://web.archive.org/web/20250302235943/https://ift.onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2621.1966.tb03285.x |url-status=live |url-access=subscription }}</ref>  This is a similar set up to that used in a [concrete slump test](/source/concrete_slump_test) using an Abrams cone, though that measures the vertical difference in slump and not the horizontal flow.<ref name="TCS">{{cite web |title=Slump test |url=https://www.concrete.org.uk/fingertips-nuggets.asp?cmd=display&id=559 |website=The Concrete Society |access-date=9 March 2025 |language=en |archive-date=9 December 2024 |archive-url=https://web.archive.org/web/20241209080816/https://concrete.org.uk/fingertips-nuggets.asp?cmd=display&id=559 |url-status=live }}</ref>

==See also==
* [Angle of repose](/source/Angle_of_repose)
* [Concrete slump test](/source/Concrete_slump_test)
* [Flow table test](/source/Flow_table_test)
* [Thickened fluids](/source/Thickened_fluids)

==References==
{{Reflist}}

Category:Fluid mechanics
Category:Food analysis
Category:Measuring instruments

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Adapted from the Wikipedia article [Consistometer](https://en.wikipedia.org/wiki/Consistometer) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Consistometer?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.