Editing Isinglass

{{short description|Substance obtained from the dried swim bladders of fish}}
{{For|the material used as window sheets|mica}}
{{Other uses}}
[[File:Colla di pesce.JPG|thumb|Isinglass]]
[[File:Swim bladder.jpg|thumb|Swim bladder of a [[common rudd|rudd]] (''Scardinius&nbsp;erythrophthalmus'')]]

'''Isinglass''' ({{IPAc-en|ˈ|aɪ|z|ɪ|ŋ|ɡ|l|æ|s|,_|-|ɡ|l|ɑː|s}} {{respell|EYE|zing|gla(h)ss}}) is a form of [[collagen]] obtained from the dried [[swim bladder]]s of [[fish]]. The English word origin is from the obsolete Dutch ''huizenblaas'' – ''huizen'' is a kind of [[sturgeon]], and  ''blaas'' is a bladder,<ref>(Chambers 20th century dictionary)</ref> or German ''Hausenblase'', meaning essentially the same.<ref>{{cite journal|last=Wedgwood|first=Hensleigh|author-link=Hensleigh Wedgwood|title=On False Etymologies|journal=Transactions of the Philological Society|url=https://babel.hathitrust.org/cgi/pt?id=uc1.b3924121;view=1up;seq=76|year=1855|issue=6|pages=66}}</ref> The bladders, once removed from the fish, processed, and dried, are formed into various shapes for use.

It is used mainly for the [[Clarification (wine)|clarification]] or fining of some [[beer]] and [[wine]]. It can also be cooked into a paste for specialised [[Fish glue|gluing]] purposes.

Although originally made exclusively from sturgeon, especially [[Beluga (sturgeon)|beluga]], in 1795 an invention by [[William Murdoch]] facilitated a cheap substitute using [[cod]]. This was extensively used in [[United Kingdom|Britain]] in place of [[Russia]]n isinglass, and in the US hake was important. In modern British brewing all commercial isinglass products are blends of material from a limited range of tropical fish.<ref>{{cite journal |vauthors=Baxter ED, Cooper D, Fisher GM, Muller RE |title=Analysis of Isinglass Residues in Beer |journal=Journal of the Institute of Brewing |date=2007 |volume=13 |issue=2 |pages=130–134 |doi= 10.1002/j.2050-0416.2007.tb00268.x }}</ref> 

== Foods and drinks ==
[[file:Topping up the barrel with finings.jpg|thumb|Adding finings to a [[cask]] of beer]]

Before the inexpensive production of [[gelatin]] and other competing products, isinglass was used in confectionery and desserts such as fruit jelly and ''[[blancmange]]''.

Isinglass [[finings]] are widely used as a processing aid in the British brewing industry to accelerate the fining, or clarification, of beer. It is used particularly in the production of cask-conditioned beers, although many [[cask ale]]s are available which are not fined using isinglass. The finings [[flocculation|flocculate]] the live [[yeast]] in the beer into a jelly-like mass, which settles to the bottom of the cask. Left undisturbed, beer will clear naturally; the use of isinglass finings accelerates the process. Isinglass is sometimes used with an auxiliary fining, which further accelerates the process of sedimentation.

Non-cask beers that are destined for [[keg]]s, [[Beverage can|can]]s, or [[bottle]]s are often [[pasteurization|pasteurised]] and [[filtration|filtered]]. The yeast in these beers tends to settle to the bottom of the storage tank naturally, so the sediment from these beers can often be filtered without using isinglass.{{Citation needed|date=July 2008}} However, some breweries still use isinglass finings for non-cask beers, especially when attempting to repair bad batches.

Many [[vegetarian]]s<ref>{{cite web |url=http://www.barnivore.com/ |title=Is your booze vegan? |publisher=barnivore.com |access-date=21 December 2012 }}</ref> consider beers that are processed with these finings (such as most [[Cask ale|cask-conditioned ales]] in the UK<ref>{{Cite web |last=Jackson |first=Michael |date=1994-07-22 |title=Food and Drink: Gingering up the real ale range: Michael Jackson enjoys the unusual flavours of a brewery deep in the Forest of Dean |url=https://www.independent.co.uk/life-style/food-and-drink/food-and-drink-gingering-up-the-real-ale-range-michael-jackson-enjoys-the-unusual-flavours-of-a-brewery-deep-in-the-forest-of-dean-1415784.html}}</ref>) to be unsuitable for [[Vegetarianism|vegetarian diet]]s (although acceptable for [[pescetarian]]s).<ref>{{Cite news |date=2016-09-15 |title=The fishy ingredient in beer that bothers vegetarians |url=https://www.bbc.co.uk/news/uk-england-37350233 |access-date=2024-12-27 |work=BBC News |language=en-GB}}</ref> According to global data in 2018, along with low-calorie beer and gluten-free beer, beers that are acceptable for strict vegetarians are expected to grow in demand in the coming years. The demand increase is attributed to [[millennials|millennial]] consumers, and some companies have introduced vegetarian friendly options or done away with isinglass use.<ref>{{cite web |author=Rachel Arthur |url= https://www.beveragedaily.com/Article/2018/05/09/Low-calorie-vegan-and-gluten-free-beers-win-favor-with-millennial-consumers |title=Low calorie, vegan and gluten-free beers win favor with millennial consumers |date=9 May 2018 |website=Beverage daily.com}}</ref> A beer-fining agent that is suitable for vegetarians is [[Chondrus crispus|Irish moss]], a type of [[red algae]] containing the polymer chemical [[carrageenan]].<ref>{{cite web |url=https://www.mirror.co.uk/news/uk-news/guinness---may-contain-fish-476494 |title=Guinness - 'May Contain Fish' |date=21 May 2007 |author=Kate Jackson, Sara Wallis |work=Daily Mirror |access-date=21 December 2012 }}</ref> However, carrageenan-based products (used in both the boiling process and after [[fermentation (beer)|fermentation]]) primarily reduce hazes caused by [[protein]]s, but isinglass is used at the end of the brewing process, after fermentation, to remove [[yeast]]. Since the two fining agents act differently (on different haze-forming particles), they are not interchangeable, and some beers use both.

Isinglass finings are also used in the production of [[kosher wine]]s, although for reasons of [[kashrut]], they are not derived from the [[Beluga (sturgeon)|beluga sturgeon]], because this fish is not kosher.<ref name="Noda" /> Whether the use of a nonkosher isinglass renders a beverage nonkosher is a matter of debate in Jewish law. Rabbi [[Yehezkel Landau]], in ''Noda B'Yehuda'', first edition, Yore Deah 26, for example, permits such beverages.<ref name="Noda">{{cite web |url=https://www.hebrewbooks.org/pdfpager.aspx?req=1497&pgnum=73 |script-title=he:נודע ביהודה מהדורה קמא, יורה דעה, כ"ו |publisher=The Society for Preservation of Hebrew Books |language=he |access-date=21 December 2012 }}</ref> This is the position followed by many kashrut-observant Jews today.{{Citation needed|date=May 2012}}

The similar-sounding names has resulted in confusion between isinglass and [[waterglass]], especially as both have been used to preserve eggs.<ref>{{cite web |url=https://www.1900s.org.uk/1940s50s-preserving-eggs-isinglass.htm |title=How isinglass was used to preserve eggs. |access-date=9 May 2021}}</ref><ref>{{cite web |url=https://www.1900s.org.uk/1940s50s-preserving-eggs.htm |title=How waterglass was used to preserve eggs |access-date=9 May 2021}}</ref> A solution of isinglass was applied to eggs and allowed to dry, sealing their pores. Waterglass is sodium silicate. Eggs were submerged in solutions of waterglass, and a gel of silicic acid formed, also sealing the pores of the eggshell.

== Conservation ==

Isinglass is also used as an adhesive to repair [[parchment]], stucco and damage to paintings on canvas. Pieces of the best Russian isinglass are soaked overnight to soften and swell the dried material. Next, it is cooked slowly in a [[double boiler]] at 45&nbsp;°C while being stirred. A small amount of [[gum tragacanth]] dissolved in water is added to the strained isinglass solution to act as an [[emulsifier]].

When repairing paint that is flaking from parchment, isinglass can be applied directly to an area which has been soaked with a small amount of [[ethanol]]. It is typically applied as a very tiny drop that is then guided, with the help of a [[binocular microscope]], under the edges of flaking paint.

It can also be used to coat tissue or [[goldbeater's skin]]. On paintings this can be used as a temporary backing to either canvas patches or filler until dried. Here, isinglass is similar to parchment [[Sizing|size]] and other forms of gelatin, but it is unique in that as a dried film the [[adhesive]] can be reactivated with moisture. For this use, the isinglass is cooked with a few drops of [[glycerin]] or [[honey]].
This adhesive is advantageous in situations where minimal use of water is desired for the parchment as the isinglass can be reactivated with an ethanol-water mixture. It also has a greater adhesive strength than many other adhesives used for parchment repair.<ref>{{cite journal |last=Quandt |first=Abigail B. |date=1996 |title=Recent Developments in the Conservation of Parchment Manuscripts |publisher=The American Institute for Conservation |journal= The Book and Paper Group Annual |s2cid=190456099 |s2cid-access=free |url=https://pdfs.semanticscholar.org/50a8/0ab2039432d9d5326c39ae52f8419142ced2.pdf |archive-url=https://web.archive.org/web/20200212005651/https://pdfs.semanticscholar.org/50a8/0ab2039432d9d5326c39ae52f8419142ced2.pdf |url-status=dead |archive-date=2020-02-12 |access-date=2020-07-21}}</ref>

== In popular culture ==

In the musical ''[[Oklahoma!]]'', the song "[[The Surrey With the Fringe on Top]]" describes the [[Surrey (carriage)|surrey]] as having "isinglass curtains you can roll right down" although here the term refers to [[mica]], commonly used for windows in vehicle side screens (but totally inflexible).<ref>{{Cite web|url=https://genius.com/Gordon-macrae-the-surrey-with-the-fringe-on-top-lyrics|title=Gordon MacRae – The Surrey With the Fringe on Top|website=genius.com}}</ref><ref>{{cite book |last1=Smith |first1=Andrew F. |title=The Oxford encyclopedia of food and drink in America |date=2013 |publisher=Oxford University Press |location=New York, NY |isbn=9780199734962 |edition=2nd|page=345}}</ref> Mentioned several times in chapter 68 of ''[[Moby Dick]]'' by [[Herman Melville]], in a discussion of whale skin and blubber.
Mentioned in ''[[The Book of Life (Harkness novel)|The Book of Life]]'' by [[Deborah Harkness]], "her scales fell like isinglass", in reference to the scales of a fire drake named Corra, and in Mark Twain's ''[[The Gilded Age: A Tale of Today|The Gilded Age]]'' where he describes a furnace door which "framed a small square of isinglass..." (chapter seven). It is also mentioned in the first paragraph of [[Willa Cather]]’s [[The Song of the Lark (novel)|The Song of the Lark]]: “the isinglass sides of the hard-coal burner were aglow.”

== References ==

{{refs}}

== Further reading ==

* {{cite book | last = Davidson | first = Alan | title = Oxford Companion to Food | year = 1999 | isbn = 0-19-211579-0 | page = [https://archive.org/details/oxfordcompaniont00davi_0/page/407 407] | chapter = Isinglass | publisher = Oxford University Press | chapter-url-access = registration | chapter-url = https://archive.org/details/oxfordcompaniont00davi_0/page/407 }}
* Woods, Chris (1995). "Conservation Treatments for Parchment Documents", ''Journal of the Society of Archivists'', Vol. 16, Issue 2, pp.&nbsp;221–239.
* [https://www.chemozyme.com/ Chemozyme] {{Webarchive|url=https://web.archive.org/web/20180921114938/https://www.chemozyme.com/ |date=21 September 2018 }}

{{use dmy dates|date=July 2020}}
[[Category:Brewing ingredients]]
[[Category:Winemaking]]
[[Category:Fish products]]
[[Category:Food ingredients]]
[[Category:Conservation and restoration materials]]