[Nhcoll-l] Alcohol concentration for terrestrial vertebrates

[John E Simmons]

Oops, I made a mistake in my previous response. Thanks to Peter Rauch for
catching it:  Proof is actually about TWICE what the ETOH concentration is,
so a 40 proof liquor would be about 20% alcohol.

The concept of proof goes back to 1705 when some measure was needed to test
the concentration of alcohol. In England, 100 proof was defined as a
concentration of 11 parts alcohol and 10 parts water, which would permit
the ignition of gunpowder. The modern definition of proof is a mixture of
alcohol and water with a specific gravity of 0.91984, or about twice the
concentration of the alcohol.

--John

John E. Simmons
Writer and Museum Consultant
Museologica
*and*
Associate Curator of Collections
Earth and Mineral Science Museum & Art Gallery
Penn State University
*and*
Investigador Asociado, Departamento de Ornitologia
Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Lima


On Fri, May 7, 2021 at 12:02 PM Mare Nazaire <mnazaire at calbg.org> wrote:

> Thank you for the citation and for all of this helpful information John!
>
> On Fri, May 7, 2021 at 8:43 AM John E Simmons <simmons.johne at gmail.com>
> wrote:
>
>> The reference for the book is:
>> Simmons, John E. 2014. *Fluid Preservation: A Comprehensive Reference*.
>> Rowman & Littlefield. It is available from Amazon.com, from the publisher,
>> and other sellers.
>>
>> The book includes a discussion (pp 54-56) of botanical fluid preservation
>> (thanks to Ann Pinzl for generously sharing with me her as yet unpublished
>> research on this subject). Botanists have tended to use some strange
>> mixtures, trying to preserve color in their specimens (particularly in
>> flowers).
>>
>> The use of beverage alcohol as a preservative has a long and fascinating
>> history. Although most beverage alcohol is below 70%, it usually does a
>> fairly good job of preservation (proof is approximately half the alcohol
>> concentration, so a 20 proof spirit is about 40% ETOH). I have used
>> beverage alcohol to preserve when nothing else was available, and have seen
>> a lot of specimens preserved in it. Rum was commonly used because it was
>> inexpensive (things such as brandy, which usually has a higher alcohol
>> content than rum, actually work better).
>>
>> Over the history of fluid preservation, there have been many attempts to
>> improve the preservative properties of alcohol. In the days before we had
>> an easy means to check the concentration, it was common to use alcohol
>> after a second distillation, which usually meant around 60-65% (depending
>> on the source), so such things as arsenic, mercuric chloride, and other
>> chemicals were commonly added to "strengthen" it (they were really just
>> making it a more effective biocide, but usually screwing up the specimen in
>> the process).
>>
>> --John
>>
>> John E. Simmons
>> Writer and Museum Consultant
>> Museologica
>> *and*
>> Associate Curator of Collections
>> Earth and Mineral Science Museum & Art Gallery
>> Penn State University
>> *and*
>> Investigador Asociado, Departamento de Ornitologia
>> Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Lima
>>
>>
>> On Fri, May 7, 2021 at 10:56 AM Mare Nazaire <mnazaire at calbg.org> wrote:
>>
>>> Thank you Simon and Dirk for your feedback on this.
>>>
>>> I had actually spoken with the botanist who originally prepared the
>>> specimens back in the 60's - he noted that they were preserved in 50% EtOH.
>>> He also noted that when he had traveled to other countries for field work
>>> and EtOH wasn't available he would use rum! So there could be some other
>>> residual components in these fluid preserved specimens!
>>>
>>> On Fri, May 7, 2021 at 7:18 AM Simon Moore <couteaufin at btinternet.com>
>>> wrote:
>>>
>>>> Dear Mare,
>>>>
>>>> I have always fixed fresh plant material in Kew mix and then
>>>> transferred to Copenhagen mixture which is similar but minus the formalin.
>>>> As Dirk has pointed out, the formulae (proportions) do vary slightly
>>>> between institutions, some prefer more glycerine in their mixes but which
>>>> can make the specimens rather translucent which is why others prefer a
>>>> lower concentration.  There is also the slight problem of osmotic pressure
>>>> differential and specimens floating until they equilibrate!
>>>> Make sure that the pH of the solutions is a near to 7.0 as possible.
>>>>
>>>> With all good wishes, Simon
>>>>
>>>> Simon Moore MIScT, RSci, FLS, ACR
>>>> Conservator of Natural Sciences and Cutlery Historian,
>>>>
>>>> www.natural-history-conservation.com
>>>>
>>>>
>>>>
>>>>
>>>> On 7 May 2021, at 13:53, Mare Nazaire <mnazaire at calbg.org> wrote:
>>>>
>>>> This is a very informative and helpful thread - thank you for this!
>>>>
>>>> I presume that 70% concentration would also be suitable for plant
>>>> material preserved in spirits? I ask because I've recently discovered that
>>>> some of our collection of fluid preserved plant material is at a
>>>> concentration of 50% and I wondered if it is advisable to keep them as is
>>>> or change their concentration to 70%. Are there recommendations in John
>>>> Simmon's book for preserving plant specimens in alcohol and could you also
>>>> provide the citation for this book?
>>>>
>>>> Thank you,
>>>> ~Mare
>>>>
>>>> On Fri, May 7, 2021 at 12:48 AM Erik Åhlander <Erik.Ahlander at nrm.se>
>>>> wrote:
>>>> Dear Tonya, John, Simon, Dirk - well all,
>>>>
>>>>
>>>>
>>>> Also I agree. Since I will soon retire I want to share some experiences:
>>>>
>>>> When we started to take care of the collection of wet vertebrates in
>>>> Stockholm in 1975 there was no overlap in time (well 1 week) with the
>>>> previous staff (the previous curator was employed 1934-1974). So we had to
>>>> invent the wheel. The initial ambition was to keep a concentration between
>>>> 70 and 80% ethanol. (We also tested the new suggested conservation fluid
>>>> Phenoxetol, which after some years showed to be a disaster). To compensate
>>>> for evaporation, we tried to stick to 80%. New material was fixed in
>>>> formalin for at least a week, washing in water, 20% ethanol for two days or
>>>> more, 50% for two days or more, and final storage in 80%. Also we removed
>>>> all bad jars from the collection – and a bad jar was a jar that needed
>>>> topping. Expedition material was sorted and identified etc after this stage
>>>> with the result that many specimens was changed to 80% once more. It took
>>>> more than 10 years to realize that 80% was to strong. But also that every
>>>> change of alcohol, or topping, resulted in a higher concentration ethanol
>>>> since the lowering effect of the alcohol concentration through remnants of
>>>> the previus stage fluid inside the specimens was removed. Also the small
>>>> amounts of formalin in the specimen was reduced for each change of fluid.
>>>> Especially for tiny fish we could find obvious shrinking. Today we are
>>>> careful
>>>>
>>>> 1.       To keep the specimens in 70% (not more, not less)
>>>>
>>>> 2.       Not to rinse to much in water. Rather remove the formalin from
>>>> the surface of the specimen only.
>>>>
>>>> 3.       Don´t change the fluid if it is not necessary.
>>>>
>>>> 4.       If you have to remove all fluid, add maybe 80-90% of fresh
>>>> (70%) ethanol and the rest used ethanol from another specimen.
>>>>
>>>> All formalin fixed specimens has a small amount of formalin left - that
>>>> is good.
>>>>
>>>> Some substances in the specimen dissolve in the alcohol (just look at
>>>> an alcohol preserved Anguilla…). Every change of alcohol add to the
>>>> removing of lipids etc - that is bad.
>>>>
>>>>
>>>>
>>>> As far as we know, formalin was used for the first time at the NRM in
>>>> 1904, but only occasionally! Still in the 1940s ethanol was commonly used
>>>> for fixation in the field. When the museum moved from downtown Stockholm to
>>>> north of the city in 1916, the economy for alcohol was reduced due to world
>>>> war I (otherwise Sweden was not involved). This led to the invention to use
>>>> a diluted formalin solution for the exhibition jars (for specimens fixed in
>>>> ethanol!). The research collection continued to be stored in ethanol. Our
>>>> collection is old. We estimate that our oldest specimens in ethanol are
>>>> from the 1720s (from the Seba collection). Still many specimens from before
>>>> 1758 are in remarkable good condition. In some specimens it is even
>>>> possible to get small pieces of DNA with ancient DNA technic – but usually
>>>> not. This sounds contradicting to some statements above. We don’t know too
>>>> much about the preservation history of these specimens, but what we know
>>>> might be of general interest. The initial fixation and preservation was in
>>>> distilled wine (=“spiritus vini”). We don’t know the concentration, and
>>>> probably it was not pure ethanol, but also contained small amount of other
>>>> fractions from the wine, more like strong cognac. The Royal collection (of
>>>> king Adolf Fredrik with many Linnaean types) was donated to the
>>>> Royal Swedish Academy of Sciences in 1801. NRM was founded in 1819, but
>>>> immediately in practice fused with the Academy. In 1848 the collections of
>>>> the Academy was formally donated to the Museum. From the 1740s to 1970 this
>>>> collection of  vertebrates in alcohol was moved four times. Jars and fluid
>>>> was probably changed twice. But most of the time the collection was stored
>>>> cool and dark. Glasses and fluids was expensive so the ratio: specimen
>>>> volume / conservation fluid volume was high up to 1900.  From 1801-1898 the
>>>> major part seems to have been almost untouched, except that the whole
>>>> collection was moved 1500 meters in 1829.
>>>>
>>>>
>>>>
>>>> I was once asked how long a specimen could be stored in alcohol. With
>>>> the reservation that our old specimens will be stored like today, no sudden
>>>> disasters etc (and no climate change), I decided that to 2220 = 500 years
>>>> would be possible, maybe 1000 years.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Erik Åhlander
>>>>
>>>> vertebrate zoology and museum history
>>>>
>>>>
>>>>
>>>> ZOO
>>>>
>>>> Swedish Museum of Natural History
>>>>
>>>> PO Box 50007
>>>>
>>>> SE-10405 Stockholm
>>>>
>>>> Sweden
>>>>
>>>> +46 0 8 5195 4118
>>>>
>>>> +46 0 70 225 2716
>>>>
>>>> erik.ahlander at nrm.se
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Från: Nhcoll-l <nhcoll-l-bounces at mailman.yale.edu> För Dirk Neumann
>>>> Skickat: den 7 maj 2021 08:36
>>>> Till: nhcoll-l at mailman.yale.edu
>>>> Ämne: Re: [Nhcoll-l] Alcohol concentration for terrestrial vertebrates
>>>>
>>>>
>>>>
>>>> Hi Tonya (and John and Simon ;-)
>>>>
>>>>
>>>>
>>>> concur with John and Simon, specimens should be kept in 70%; Simon
>>>> pointed to the diluting effects and the image below nicely illustrates
>>>> this: even if you use more steps for transferring specimens (0/20/40/60/80
>>>> vs. 20/30/50/70), tissues are still soaked with 60% or less high
>>>> concentrated EtOH.
>>>>
>>>>
>>>>
>>>> Depending on size, body mass and number of specimens (i.e. amount of
>>>> tissue in the jar), the effect can be considerable (see "staining" in the
>>>> images below; in the left one, body fluids released from these tall
>>>> whitefish are indicated by the reddish haemoglobin stain at the bottom of
>>>> the jar, the overall greenish colour in the right comes from chlorophyll
>>>> released from the guts of these herbivorous distichodus fish).
>>>>
>>>>
>>>>
>>>> I do the initial filling usually with 73-75% EtOH to reach 70%; aside
>>>> from vertebrates high EtOH concentrations can be an issue in malaise traps
>>>> because there the specimens usually are collected over several days or
>>>> weeks in 96-80% EtOH. As Simon pointed out this quickly dehydrates
>>>> specimens and weakens the joints holding all the antennae, appendices,
>>>> bristles of invertebrates. Another issue is that in unsorted malaise trap
>>>> samples there often is a thick deposit of specimens at the bottom of the
>>>> container. Because the diluted less high concentrated ethanol is heavier,
>>>> it layers at the bottom of the jar (cf. whitefish jar). Inside malaise trap
>>>> containers, this diluted EtOH may get trapped in the thick specimen deposit.
>>>>
>>>>
>>>>
>>>> Usually, I leave jars for few day to see if there are any unwanted
>>>> effects before moving them into the collection.
>>>>
>>>>
>>>>
>>>> Hope this is useful, with best wishes
>>>>
>>>> Dirk
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> <image001.png>
>>>>
>>>>
>>>>
>>>> Am 07.05.2021 um 00:17 schrieb Simon Moore:
>>>>
>>>> Thanks John and Tonya,
>>>>
>>>>
>>>>
>>>> What John says is true about the staging of alcohols and the final
>>>> concentrations.  80% was what I was advised at the NHM in London when I
>>>> worked there and by the time larger terrestrial vertebrates ‘end up’ in
>>>> 80%, you will often find that with the mix of lower grade alcohols from the
>>>> staging process, once things have settled down / equilibrated, then the net
>>>> result is around 70% anyway.  Higher grade alcohols  can lead to
>>>> embrittlement of certain tissues as well as evaporation issues.
>>>>
>>>>
>>>>
>>>> I have also found the staging process necessary for the more fragile
>>>> specimens as they undergo changes in Osmotic pressure during this process
>>>> which can cause syneresis or shrinkage in softer tissues.
>>>>
>>>>
>>>>
>>>> With all good wishes, Simon
>>>>
>>>> Simon Moore MIScT, RSci, FLS, ACR
>>>> Conservator of Natural Sciences and Cutlery Historian,
>>>>
>>>> www.natural-history-conservation.com
>>>>
>>>>
>>>> <image002.jpg>
>>>>
>>>>
>>>>
>>>>
>>>> On 6 May 2021, at 22:50, John E Simmons <simmons.johne at gmail.com>
>>>> wrote:
>>>>
>>>> Tonya,
>>>> Thank you for your kind words about my book. The recommendation for
>>>> staging up to 80% concentration was by made by my friend Simon Moore, who I
>>>> cited in that sentence. In general, I do not recommend using 80% ETOH as a
>>>> preservative for terrestrial vertebrates, but rather 70%. Preservation is
>>>> alcohol is a trade-off between dehydration of the specimens and providing
>>>> them suitable protection against biological deterioration. At 70%, ETOH is
>>>> a very good biocide; below that, not so good, and above 70%, too strong for
>>>> most specimens (note that there are some instances in which 80% might be
>>>> preferred).
>>>>
>>>> I do not recommend using stronger alcohol as a hedge against
>>>> evaporation--that leads to uneven concentrations of preservatives and can
>>>> be a real mess to work with in a collection.
>>>>
>>>> For how-to instructions on preserving, transferring specimens, and
>>>> managing a fluid preserved collection, you might want to check
>>>> Herpetological Collecting and Collections Management (3rd edition, 2015).
>>>> The instructions for preserving and managing fluid preserved animals will
>>>> work for most other specimens as well as for reptiles and amphibians.
>>>>
>>>> Hope this helps,
>>>> --John
>>>>
>>>> John E. Simmons
>>>> Writer and Museum Consultant
>>>> Museologica
>>>> and
>>>> Associate Curator of Collections
>>>> Earth and Mineral Science Museum & Art Gallery
>>>> Penn State University
>>>> and
>>>> Investigador Asociado, Departamento de Ornitologia
>>>> Museo de Historia Natural, Universidad Nacional Mayor de San Marcos,
>>>> Lima
>>>>
>>>>
>>>> On Thu, May 6, 2021 at 4:05 PM Haff, Tonya (NCMI, Crace)
>>>> <Tonya.Haff at csiro.au> wrote:
>>>> Hello all,
>>>>
>>>> I am enjoying reading John Simmon's fantastic book on fluid
>>>> preservation. In it I read one suggestion for stepping specimens up out of
>>>> formalin fixative into preservation alcohol as follows: from 20% ETOH to
>>>> 40% to 60% and finally to 80%. We typically place our specimens in 70%
>>>> ETOH, and I know higher concentrations can cause some problems with
>>>> specimen dehydration. All our specimens are terrestrial vertebrates. I
>>>> presume the final 80% provides a buffer against ETOH evaporation or
>>>> leaching of water from the specimen into the fluid in the jar, to ensure
>>>> that the alcohol concentration in the preservation fluid stays sufficiently
>>>> high? But to me this is not quite clear. I wonder if any of you have
>>>> thoughts on this, or if you would be willing to share how you step your
>>>> specimens up in ETOH?
>>>>
>>>> Thank you!
>>>>
>>>> Tonya
>>>>
>>>>
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>>>> society. See http://www.spnhc.org for membership information.
>>>> Advertising on NH-COLL-L is inappropriate.
>>>>
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>>>>
>>>>
>>>>
>>>>
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>>>> _______________________________________________
>>>> 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.
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>>>>
>>>> --
>>>>
>>>> <image004.png>
>>>>
>>>>
>>>> Dirk Neumann
>>>>
>>>> Tel: 089 / 8107-111
>>>> Fax: 089 / 8107-300
>>>> neumann(a)snsb.de
>>>>
>>>> Postanschrift:
>>>>
>>>> Staatliche Naturwissenschaftliche Sammlungen Bayerns
>>>> Zoologische Staatssammlung München
>>>> Dirk Neumann, Sektion Ichthyologie / DNA-Storage
>>>> Münchhausenstr. 21
>>>> 81247 München
>>>>
>>>> Besuchen Sie unsere Sammlung:
>>>> http://www.zsm.mwn.de/sektion/ichthyologie-home/
>>>>
>>>> ---------
>>>>
>>>> Dirk Neumann
>>>>
>>>> Tel: +49-89-8107-111
>>>> Fax: +49-89-8107-300
>>>> neumann(a)snsb.de
>>>>
>>>> postal address:
>>>>
>>>> Bavarian Natural History Collections
>>>> The Bavarian State Collection of Zoology
>>>> Dirk Neumann, Section Ichthyology / DNA-Storage
>>>> Muenchhausenstr. 21
>>>> 81247 Munich (Germany)
>>>>
>>>> Visit our section at:
>>>> http://www.zsm.mwn.de/sektion/ichthyologie-home/
>>>>
>>>> _______________________________________________
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>>>> 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.
>>>>
>>>>
>>>> --
>>>> Mare Nazaire, Ph.D.
>>>> Administrative Curator, Herbarium [RSA-POM]
>>>> California Botanic Garden
>>>> Research Assistant Professor, Claremont Graduate University
>>>> 1500 North College Avenue
>>>> Claremont, California 91711
>>>> 909.625.8767 ext. 268
>>>> _______________________________________________
>>>> Nhcoll-l mailing list
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>>>> 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.
>>>>
>>>>
>>>>
>>>
>>> --
>>> Mare Nazaire, Ph.D.
>>> Administrative Curator, Herbarium [RSA-POM]
>>> California Botanic Garden
>>> Research Assistant Professor, Claremont Graduate University
>>> 1500 North College Avenue
>>> Claremont, California 91711
>>> 909.625.8767 ext. 268
>>> _______________________________________________
>>> 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.
>>>
>>
>
> --
> Mare Nazaire, Ph.D.
> Administrative Curator, Herbarium [RSA-POM]
> California Botanic Garden
> Research Assistant Professor, Claremont Graduate University
> 1500 North College Avenue
> Claremont, California 91711
> 909.625.8767 ext. 268
>
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