Tuesday, April 12, 2011

Word: Isinglass

In my last post (on some British vocabulary) I mentioned blancmange, giving the first part of the definition from the (century-old) Century Dictionary. It’s worth quoting in full:
Blancmange: In cookery, a name of different preparations of the consistency of jelly, variously composed of dissolved isinglass, arrowroot, corn-starch, etc., with milk and flavoring substances. It is frequently made from a marine alga, Chondrus crispus, called Irish moss, which is common on the coasts of Europe and North America. The blancmanger mentioned by Chaucer in the General Prologue to the Canterbury Tales, 1. 387, was apparently a compound made of capon minced with flour, sugar, and cream.
One of the commenters, Gil, didn’t see how the isinglass he knew could be edible:
I dunno where that cockamamie reference book got isinglass and such. Who today knows what isinglass is? I have seen some as a kid -- it's a transparent sort of quartz that can be split into thin sheets (and used for windows on the surrey with the fringe on top). … I don't think the FDA would approve of an isinglass pudding nowadays.
Like Gil, I knew the isinglass that was translucent (and a feature of the pretty little surrey in the song from “Oklahoma!”). But I also vaguely knew it was an animal product. So what is it really?

It’s both. The original isinglass (first OED cite 1545) is "a firm whitish semitransparent substance (being a comparatively pure form of gelatin) obtained from the sounds or air-bladders of some fresh-water fishes, esp. the sturgeon; used in cookery for making jellies, etc., also for clarifying liquors, in the manufacture of glue, and for other purposes." The word may be “a corruption or imperfect imitation of an obsolete Dutch huisenblas (Kilian huysenblase, huysblas), German hausenblase isinglass, lit. ‘sturgeon's bladder.’”

Two centuries later, the second sense of isinglass appears: “A name given to mica, from its resembling in appearance some kinds of isinglass.”

Whether this isinglass could be used in curtains that would "roll right down, in case there's a change in the weather" is still being debated. Luckily for me (and you), Joel Segal, a bookseller in England, looked into the matter quite thoroughly in January at his blog. The fish-based isinglass, he reports, "was a versatile and expensive commercial product, used as a gum, a food gelling agent, as the sticking medium for surgical plasters, as stiffener for cloth, as a sealant for preserving eggs, and for making mock pearls."

The other isinglass, he says, is
the transparent variety -- otherwise called muscovite -- of the mineral mica. In some parts of world, notably Russia (hence the name muscovite -- i.e. pertaining to Moscow), it's found in large enough sheets to make small window panes, so it was historically used for applications where tough, slightly flexible, heat-resistant, transparent material was needed, such as furnace or lantern windows.
But in actual usage, he finds, the two substances -- both now unfamiliar -- have often been conflated or confused. Thanks for all your research, Joel!


Anonymous said...

ice in glass / i sing, lass

Ø said...

Wow. I always thought it was just sheets of mica (and was a little surprised by the idea that big sheets of mica were available in suitable quantities).

And as a bonus treat we learn that the word "sound" can mean the air bladder of a fish.

John L said...

"The wheels are yeller, the upholstery's brown,
The dashboard's genuine leather,
With isinglass curtains y' can roll right down,
In case there's a change in the weather."
-from The Surrey With The Fringe On Top,

T. Roger Thomas said...

I remember discussing the black glop in a course on Chaucer I took at the University.

fizzog said...

I was at Adnam's Brewery in Stowmarket, Suffolk, England the other week, and they still use isinglass commercially as finings to clear the sediment from the beer in the final stages of the brewing process.

~Heidi~ said...

It seems to me that anything used to thicken or gel edible substances comes from some sort of disgusting animal product. Fish bladders, pigs feet ... even cornstarch is used in some plastic production. I almost wish I didn't know these things.

Warsaw Will said...

Maybe it's because I'm British, but I think I only knew about the fish type, even though I was brought up on Rogers and Hammerstein. Perhaps I thought they were some weird fishy kind of curtains.

Anonymous said...

I actually remember both forms of isinglass from my childhood (and I'm only 47 - but I did grow up in the country). My grandfather would regularly use the liquid form to "fine" his brew of beer, and a neighbour of ours used small sheets of the solid version in woodstoves he manufactured. I never really thought much about the obvious contradiction of usage - thanks for giving me something to think about!

PS: I also used to confuse the liquid form with another compound - waterglass, or sodium silicate - that my father used to waterproof concrete.

Mae Travels said...

It's still used in winemaking -- vegetarians worry about it, home wine makers buy it, how-to articles explain it...

Murr Brewster said...

I remember at summer camp there was mica dust all over the campground. The counselors said it was fairy dust and the fairies would tell on us if we ventured outside at night. My sister was a rockhound and I knew it was mica, and told them so. I was eight. I didn't know where babies came from, but I knew from fairy dust.

cucaracha said...

i thought isinglass was used to filter wine. Which is why there is "vegetarian" wine, one filtered using something else.
In pre-refrigeration times, ising glass was also used to preserve eggs for times when chickens were off lay.
It is a very useful means of preservation.

Jed Waverly said...

I remember the isinglass window on our furnace. It never occurred to me to ask about the source of it. I just thought it was another form of glass. I just knew that it stayed transparent (for the most part) and didn't let the heat escape. I never knew there was a food type! Yuk!

Kickboxing Los Angeles said...

I would hate to be the person that gets the wrong kind of Isinglass. Can you imagine showing up with a sheet instead of the gelatin form? 'Uh, Bob... That's not what we had in mind.'