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Since the mid to late 19th century, isinglass, a fish by-product has been used as a clarification agent in Guinness beer. Image courtesy of Wikimedia Commons.

Guinness sells about 10 million pints a day across 100 countries. On St. Patrick’s Day, that number hops to 13 million. When Arthur Guinness set up shop in Dublin back in 1759, he never would’ve guessed that his stout would become the unofficial beer of the Irish and the go-to beverage to shout to the bartender come March 17 (besides Jameson). Even Obama honored his Irish lineage with a highly-publicized Guinness at a pub in Ireland last year. But the classic brew isn’t for everyone. For the hardline vegetarians and vegans out celebrating this St. Paddy’s Day: there could be traces of fish bladder in your Guinness.

Isinglass, a gelatine-like substance made from the air-bladders or sounds of fish like the sturgeon is added to cask beers like Guinness to help any remaining yeast and solid particles settle out of the final product. As the finings pass through the beer, they attract themselves to particles in the fermented beer that create an unwanted “haziness” in the final product and form into a jelly-like mass that settles to the bottom of the cask. While beer left untouched will clear on its own, isinglass speeds up the process and doesn’t affect the final flavor of the beer once removed.

The word isinglass most likely comes from the corruption of the Dutch word huisenblas which translates directly to “sturgeon’s bladder,” but its history goes back a little further. Its archaic, Latin root, ichthyocolla, comes from the Greek words ikhthus (fish) and kolla (glue)—defining the mucous-like substance as “fish glue.”

According to the Encyclopaedia Britannica Volume IX, originally published in Edinburgh in 1797, the method of using isinglass as a clarification agent was long a secret in the hands of the Russians who were known for their exceptionally strong isinglass-made glue. The entry, which draws heavily from Humphrey Jackson’s 63rd volume of the Philosophical Transactions, cites the principal research of Pomet on the process of making isinglass:

“As to the manner of making the isinglass, the sinewy parts of the fish are boiled in water till all of them be dissolved that will disolve; then the gluey liqur is strained and set to cool. Being cold, the fat is carefully taken off, and the liquor itself boiled to a just consistency, then cut to pieces and made into a twist, bent in form of a crescent, as commonly fold: then hung upon a firing and carefully dried.”

Pomet’s experiments with the sounds of fish and its chemical properties lead him to discover the fish membrane’s ability to clarify beer. Adding an ounce and a half of “good isinglass” to a gallon of stale beer to steep for a few days, he found that the bad beer “was converted into good fining, of a remarkably thick consistence.” When he tried this with the same quantity of glue, the experiment yielded only “mucilaginous liquor, resembling diluted gum water which instead of clarifying beer, increased both its tenacity and turbidness.”

Combining the insinglass with malt liquor, he found that a “vast number of curdly masses became presently formed”, became attracted to the “feculencies of beer,” and, with the “well known laws of gravitation,” the unwanted particles combined with the isinglass and fell to the bottom of the barrel.

The process is simple: Remove the membranous parts of fresh-caught fish, scrape off the mucosity with a knife, roll, twist and dry in open air.  The thicker the sounds are, the better the isinglass. The air-bladders of fresh water fish are preferred because they are more flexible and delicate. Swim bladders from sturgeon—especially that from the Beluga sturgeon which yielded the greatest quantity of sounds—were used to make isinglass until the 1795 invention of a cheap cod substitute by William Murdoch.  Summer is the best time to collect, as frost interferes with the fish’s gelatinous principles. After the drying process, “good” isinglass, once held up to a light, exhibits prismatic colors.  

Guinness first used isinglass in its Dublin brewery in the mid to late 19th century. A young fermentation scholar by the name of Forbes Watson, the son of an Edinburgh solicitor, was a pioneer in the experimentation and examination of the mineral constituents of Guinness beer. Within six weeks of being hired at the brewery, Watson discovered a way to recover beer at the bottom of the vat saving Guinness 6,000 pounds a year. Very early in his career, he toyed with pasteurization and introduced new methods of breaking down isinglass finings that would increase the lifetime of the stout. In 1909, Watson was killed in an accident with a machine he had helped create at age 37. After he died, little scientific ground was broken for the company until the 1930s.

With the presence of modern gelatin, isinglass is rarely used today with the exception of British “real ale” cask beers. Generally, British beers still use isinglass, gelatin, glycerin or casein. According to a recent statement made by Guinness:

“All Guinness brands are free from animal matter and from contact with animal matter. However, isinglass, which is a by-product of the fishing industry, is used as a fining agent for settling out suspended matter in the vat. The isinglass is retained in the floor of the vat but it is possible that minute quantities might be carried over into the beer.”

For many strict vegetarians and vegans even “minute quantities” of an animal product is enough to abstain from eating a particular food. Much like the honey debate (Does it hurt the bee? Or does it not count as an animal product? What about silkworms and cochineal bugs?) flexitarians and militant vegans may disagree on how to classify the potential traces of isinglass in beer.

For those who are on the anti-isinglass side of the spectrum, carrageenan, a type of red algae, also called Irish Moss, (an appropriate title for St. Paddy’s Day) also works as a fining agent in beer, but doesn’t yield the same results as isinglass. The k-carrageenan interacts with the proteins that create cloudy beer and form the molecular equivalent of marbles in syrup at the bottom of the batch. Vegan brands like Deschutes Brewery in Bend, Oregon use carrageenan while others like Odell Brewing Co. use centrifugation for clarification. 

Strict vegetarians and vegans often choose German or Belgium brews which abide by “purity laws” (first enacted in 1516) which require that breweries use only ingredients of water, grain (barley or wheat), hops and yeast. The ruling was officially lifted in 1987 by the European Court, but the tradition of the law remains.

So, before you step out on the town in your green get-up and order an Irish stout this St. Patrick’s Day, remember: Pescetarians, rejoice—Guinness is still “good for you“. Vegans, stick to whiskey.

I’m not remotely Irish, but I always loved St. Patrick’s Day as a kid. My mother has a great sense of fun, especially when it comes to holidays. So on the morning of every March 17th, as my brother and I stumbled groggily downstairs for breakfast, we would be greeted with green: Green placemats; green napkins; green candles; a shiny green banner of letters strung across the dining room wall spelling out “Happy St. Patrick’s Day!”

Green food coloring in milk, courtesy Flickr user mr_orange

And best of all was our requisite daily glass of milk: On those mornings, the milk was miraculously green, with a giant marshmallow floating in it. The marshmallow was topped with a decorative plastic toothpick, shaped like a shamrock with a happy little leprechaun skipping across it.

I think this particular tradition was my mother’s unique invention (at least the marshmallow part), but I have other friends whose parents celebrated by cooking up green pancakes or “green eggs and ham,” Dr. Seuss-style, or baking batches of green-frosted cookies and cupcakes to share. And then there’s the green beer served up by many bars this time of year. It’s all made me wonder: What exactly is in green food coloring? Is it made from bugs, like red food coloring? Is it safe to consume in large quantities?

According to an article in Chemical and Engineering News, the color known as Green No. 3, or “Fast Green,” is a “petroleum-derived triphenylmethane.” Green food coloring can also be made by combining blue and yellow dyes, but either way, it’s usually synthetic. Chlorophyll would do the job naturally, but oddly enough, it’s not approved for use as a food coloring in the United States. (The FDA has only approved these nine color additives for use in food.)

The INCHEM database details the studies performed on rats, mice, hamsters and even beagles to test the safety of Green No. 3 as a food additive. It’s not exactly appetizing reading, I warn you—but basically, yes, it appears the chemical is safe to consume in small doses.

On the other hand, the Center for Science in the Public Interest recently included Green No. 3 on a list of artificial food dyes linked to behavior problems like ADHD in children. (Blue 1 dye, used in at least one popular brand of green food coloring, is also on the list of suspects.)

Judge for yourself, but personally, I’m concluding that a glass of green milk once a year is nothing to fear—and beyond that, I’ll stick to getting my greens in the form of vegetables.

An old Guinness poster, courtesy of Flickr user Joan_Thewlis

Happy St. Patrick’s Day, the one day of the year when eating your greens can mean cupcakes, beer, even bacon.

It’s oddly appropriate that we celebrate our country’s Irish heritage by binging on fatty food and drink; after all, Ireland is the home of the fry-up, a typical breakfast consisting of fried eggs, bacon (rashers), sausages and black pudding (made from pig’s blood), with a few other fried things thrown in for good measure. Not surprisingly, Ireland’s also near the top of the list of countries with the highest heart disease death rates.

But there is some good health-related news on the Irish front: You know those charming old Guinness beer ads that proclaim it to be good for you? Turns out, they might be right—though not for the reasons originally thought.

Back in the 1920s, when the “Guinness is Good for You” slogan was introduced, the claim was based on market research that found that people felt good after they drank a pint of the dark and foamy stout. Um, duh.

This flimsy claim was eventually bolstered by the fact that Guinness contains iron. Pregnant women were even advised to have an occasional pint. Of course, it would take something like a dozen pints a day for a woman to get her recommended daily allowance of iron, in which case the alcohol and calories would cause more harm than good.

But another health benefit was discovered in 2003: stout beer like Guinness (as opposed to lager and other light beer) is high in the antioxidant compounds called flavonoids—similar to those found in red wine, tea and chocolate—that can reduce the risk of heart attack from blood clotting. Researchers at the University of Wisconsin carried out laboratory tests on dogs (Irish setters, I wonder?) with clogged arteries, comparing the effects of Guinness and Heineken. Only those dogs fed Guinness had reduced clotting.

In the interest of having a heart-healthy St. Pat’s Day, I decided to double my antioxidant dose by baking a Chocolate Guinness Cake. A little tip from this novice baker: measure the amount of Guinness carefully. I lost track of how much I put in, and ended up with a cake batter volcano in my oven. Luckily, I was able to scoop out about a 1/3 of the batter and bake the remainder. I doubt it came out the way it was supposed to, but it was still pretty delicious—moist and flavorful.

And one last interesting fact I learned about Guinness—it isn’t vegan; it (and some other beers) contains isinglass, a fish product used in the clarifying process to get rid of excess yeast. Be sure to share that little nugget of wisdom at the pub tonight.

Now, get out there and celebrate.

Country-Western Mr. Potato Head, courtesy Flickr user Patrick Q

You know how sometimes, strangers on the plane or train will seek matter for chatter by peeking at what you’re reading? It usually works. But I’ve discovered the perfect conversational stumper: “Potato: A History of the Propitious Esculent,” a new hardcover by Yale University Press.

As they stare at the book jacket, which features a photo of a large, lone potato looming over the oddly academic title, I can guess what they’re thinking: “What kind of person wants to read an entire book about a potato ?” For that matter, who writes one? (A man named John Reader, which means I’m writing about reading a Reader’s writing. Who’s on first?) But I say to my bemused fellow passengers, and to you, that it’s a surprisingly fascinating subject.

I set out to blog about this book because of St Patrick’s Day and the potato’s reputation as the quintessential Irish food. But while the potato was indeed hugely important to Ireland in the 18th and 19th centuries, that’s not where the plant’s history is rooted, as Reader reveals in the first few pages:

“Far from being an unassuming item of food that Europeans had been eating since time immemorial (as I, like many, had once supposed), the potato is a native of South America, where it had been domesticated by the pre-Inca people of the Andes about 8,000 years ago.”

So perhaps Cinco de Mayo would have been a more apt holiday connection. Too late, I’m hooked on potato history, and you’ll have to put up with it! (And if you delve into Reader’s book, you’ll have to put up with a bit of corn as well, i.e.: “Take a close look at a potato; look deep into its eyes.”)

Nutritionally, potatoes are pretty much the complete package. They are low in fat, full of complex carbohydrates, essential amino acids, vitamins and minerals, and also contain a surprising amount of protein—on par with soybeans when ranked in terms of biological value. Studies have shown that people can live healthily for months an all-potato diet (supplemented by a little margarine or milk), although this requires eating as many as 7 pounds of potatoes a day and surely drives the palate mad with monotony.

It’s often hard to define a plant’s origin, and cultivated potatoes are “an especially difficult case” because they have so many wild relatives (at least 169) over a very wide geographic range, Reader tells us. The potato showed up in Europe during the 16th century, but the question of who brought it there remains unresolved. Some say it was Sir Francis Drake, some say Sir Walter Raleigh, but Reader doubts both versions. He suggests that Spanish conquistadors brought potato cultivars back from the Americas as early as 1562 (first to the Canary Islands, then the mainland), but may have kept the discovery of this novel food source secret from their European neighbors for a while. Reader warns us to “be wary of conspiracy theories” but thinks the evidence points to something “distinctly odd.”

Spanish conspiracy or not, potatoes were common enough in England by the turn of the 17th century to merit mention from Shakespeare, and by the late 1700s the Prussian ruler Frederick the Great had become so convinced of the potato’s merit that he ordered his subjects to grow them.

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