Consistometer

{{Short description|Device for measuring the consistency of semi-liquid foodstuffs}} {{Use dmy dates|date=March 2025}} {{multiple image | align = right | total_width = 320 | image1 = Bostwick consistometer 01.jpg | alt1 = | caption1 =A Bostwick consistometer from the top, barbecue sauce ready to be released and measured | image2 = Bostwick consistometer 02.jpg | alt2 = | caption2 = A Bostwick consistometer from the top, the release sprung and barbecue sauce flowing }}

A '''consistometer''' is a device for measuring the physical consistency of a substance. It is most often used for foods such as ketchup and other thick fluids or semi-fluids.

Consistency is typically measured in terms of rate of flow, as opposed to viscosity which is measured in regard to force within units like poise. Consistometry readings can roughly correspond with viscosity measurements, but some substances such as 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.<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 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 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 mL.<ref name="Mouquet"/> This makes it better for measuring things like 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 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>

==References== {{Reflist}}

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