[Nhcoll-l] [EXTERN] Digital Density Meter

Mon Jun 8 11:58:04 EDT 2026

I have noticed that there seems to be a bit of confusion about how the
concentration of alcohol can be measured when managing a fluid-preserved
collection (e.g., a device with no electronic or mechanical parts does not
work the same way as a digital density meter). Which one you decide to use
will depend on several factors, including cost, the amount of fluid
required, ease of use, and what fluids you are measuring.

For use in managing fluid-preserved collections, there are three basic
types of devices that are commonly used—each uses a different technology
and different amount of fluid to determine alcohol concentration (there are
other ways to measure density that are not practical for use in collection
management).

A refractometer measures the refraction angle of the light going through a
few drops of liquid and correlates it to a refractive index. Refractometers
do not work with alcohol that has glycerin added to it.

A hydrometer measures specific gravity, the old Archimedes principle of
buoyancy in which a solid body displaces its own weight within the liquid
in which it floats, and requires enough fluid and a large enough container
to float freely.

A digital density meter requires 2-3 ml of liquid which is electronically
stimulated so that the frequency of oscillations of the molecules can be
measured.

For a large, heavily used collection, a digital density meter is most
efficient. If budget is an issue and the alcohol does not have glycerin in
it, a refractometer is the least expensive option. Hydrometers are limited
by the amount of fluid being tested—small hydrometers are available but
smaller instrument have smaller the scales that are more difficult to read
and are less precise.

John E. Simmons
US Fulbright Senior Scholar
Writer and Museum Consultant, Museologica
*and*
Research Associate, Earth and Mineral Sciences Museum & Art Gallery, Penn
State University
*and*
Investigador Asociado, Departamento de Ornitología, Museo de Historia
Natural, Universidad Nacional Mayor de San Marcos, Lima

On Mon, Jun 8, 2026 at 12:41 AM Dirk Neumann <d.neumann at leibniz-lib.de>
wrote:

> Hi Katherine,
>
> many are using the handheld alcohol density meters of Anton Paar:
> https://www.anton-paar.com/corp-en/products/details/snap/
>
> Anton Paar has a worldwide distribution network and sells in Africa,
> Australasia, Europe North- and South America.
>
> Less expensive and perhaps more convenient are small traditional manual
> density meters that fit into jars. few years back, Gassner Glastechnik
> manufactured small calibrated (60/70/80 % EtOH) 5cm alcohol metres which
> allow direct measuring inside jars.
>
> The advantage is that they are small and have no electronic or mechanical
> parts that need maintenance or could fail, they also do not need
> calibration, and are easy to apply. Even though manual alcohol metres are
> less accurate and cannot show the alcohol concentration with two decimal
> places, they are accurate for fluid preserved collections.
>
> Also, alcohol metres have no tubing that need to be cleaned/rinsed after
> measuring (oils, fats, denaturing agents).
>
> Hope this helps
> Dirk
>
>
> Am 05.06.2026 um 22:42 schrieb Katherine Dunnell:
>
> Hello Everyone!
>
> Can anyone recommend a *digital density meter* they like using for wet
> collection top ups?
> Would love to hear what others are using within these collections.
> best
> Katherine
>
> *Katherine Dunnell (she/her)*
> Manager, Collections Care - Natural History
>
> 100 Queen's Park
> Toronto, ON M5S 2C6
> 416 586 5816
>
>
>
> Royal Ontario Museum is an agency of the Government of Ontario.ROM
> acknowledges that this museum sits on what has been the ancestral lands of
> the Wendat, the Haudenosaunee Confederacy,and the Anishinabek Nation,
> including the Mississaugas of the Credit First Nation, since time
> immemorial to today.
>
> Le Musée royal de l'Ontario est un organisme du gouvernement de
> l'Ontario.Le ROM reconnaît que le Musée est situé sur les terres
> ancestrales des Wendats, de la Confédération des Haudenosaunee et des
> Anishinabes, y compris la Première Nation des Mississaugas de Credit, et
> qu’ils occupent ces terres depuis la nuit des temps.
>
>
>
> On now at ROM, BEES: A Story of Survival
> <https://www.rom.on.ca/whats-on/exhibitions/bees-story-survival>. Book
> tickets at rom.on.ca <https://www.rom.on.ca>.
> ------------------------------
>
> À l'affiche : LES ABEILLES : Une histoire de survie
> <https://www.rom.on.ca/fr/a-laffiche/expositions/les-abeilles-une-histoire-de-survie>.
> Billets en vente sur rom.on.ca/fr <https://www.rom.on.ca/fr>.
>
> _______________________________________________
> Nhcoll-l mailing listNhcoll-l at mailman.yale.eduhttps://mailman.yale.edu/mailman/listinfo/nhcoll-l
>
> _______________________________________________
> NHCOLL-L is brought to you by the Society for the Preservation of
> Natural History Collections (SPNHC), an international society whose
> mission is to improve the preservation, conservation and management of
> natural history collections to ensure their continuing value to
> society. See http://www.spnhc.org for membership information.
> Advertising on NH-COLL-L is inappropriate.
>
>
> --
>
> ******
>
>
>
> *Dirk Neumann*
>
> Collection Manager, Hamburg
>
>
>
> Postal address:
>
> *Museum of Nature Hamburg*
> Leibniz Institute for the Analysis
>
> of Biodiversity Change
>
> Dirk Neumann
>
> Martin-Luther-King-Platz 3
>
> 20146 Hamburg
> +49 40 238 317 – 628
>
> *d.neumann at leibniz-lib.de <d.neumann at leibniz-lib.de>*
>
> www.leibniz-lib.de
>
>
>
> --
> Stiftung Leibniz-Institut zur Analyse des Biodiversitätswandels
> Postanschrift: Adenauerallee 127, 53113 Bonn, Germany
>
> Stiftung des öffentlichen Rechts;
> Generaldirektion: Prof. Dr. Bernhard Misof (Generaldirektor), Adrian
> Grüter (Kaufm. Geschäftsführer)
> Sitz der Stiftung: Adenauerallee 160 in Bonn
> Vorsitzender des Stiftungsrates: Dr. Michael Wappelhorst
>
>
> --
> Stiftung Leibniz-Institut zur Analyse des Biodiversitätswandels
> Postanschrift: Adenauerallee 127, 53113 Bonn, Germany
>
> Stiftung des öffentlichen Rechts;
> Generaldirektion: Prof. Dr. Bernhard Misof (Generaldirektor), Adrian
> Grüter (Kaufm. Geschäftsführer)
> Sitz der Stiftung: Adenauerallee 160 in Bonn
> Vorsitzender des Stiftungsrates: Dr. Michael H. Wappelhorst
> _______________________________________________
> Nhcoll-l mailing list
> Nhcoll-l at mailman.yale.edu
> https://mailman.yale.edu/mailman/listinfo/nhcoll-l
>
> _______________________________________________
> NHCOLL-L is brought to you by the Society for the Preservation of
> Natural History Collections (SPNHC), an international society whose
> mission is to improve the preservation, conservation and management of
> natural history collections to ensure their continuing value to
> society. See http://www.spnhc.org for membership information.
> Advertising on NH-COLL-L is inappropriate.
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.yale.edu/pipermail/nhcoll-l/attachments/20260608/3e7cd501/attachment.html>