Of Isinglass and Other Fine Additives, Or, Is That a Fish Bladder I Spy in My Beer?

Last night I finally got around to brewing my chocolate peanut porter. With the cocoa nibs and peanuts I’ll add to the fermenter, the beer is no poster child for the German Reinheitsgebot (Purity Law), but at least I got the peanuts from the local farmers’ market. Like many homebrewers, I added a smidgeon of Irish moss toward the end of the boil so that the beer will be relatively clear when I bottle it.

Irish moss is actually seaweed, a red alga that we also know as carrageenan. Irish moss combines with haze-forming proteins, and precipitates out of the beer. But Irish moss doesn’t aid in clearing yeast strains that don’t flocculate well. (A highly flocculant yeast strain is one that drops out of suspension quickly). To round up these reluctant yeasts, some brewers historical and contemporary turn to isinglass to perform the feat.

Isinglass is fish bladder.

Wait, fish bladder in my beer? The very notion of it has spawned (ahem) a spate of articles expressing righteous indignation at breweries for lacing their beer with, well, fish guts. I’ll address one of those articles here – Food Babe’s “The Shocking Ingredients in Beer” – mainly because it just made its second appearance in as many months on friends’ Facebook feeds.

Food Babe is “hot on the trail to investigate what’s really in your food.” With her article on beer, she turns up all manner of scandalous brewing transgressions, from GMO ingredients and high fructose corn syrup to harmful food colouring additives. And fish bladder.

She takes particular umbrage at the paucity of information on the labels – an issue I think merits debate. But aside from a belated nod to craft brewers and the Germans, she concludes that “if you decide to drink beer, you are definitely drinking at your own risk for more reasons than just the crazy ingredients that could be in them.”

Addressing one of Food Babe’s main concerns – the use of GMO adjuncts, particularly corn, by many of the large brewing conglomerates – is fairly straightforward: stop drinking mass-produced beer and head in search of your closest craft brewery.

Whether you’re choosing artisanal products from Europe or beers produced in your neck of the North American woods, the odds are in your favour that you’ll be getting beer made with ingredients of the highest quality.

And not only of the highest quality but, increasingly, local. New York State is only one of the most prominent examples of this steadily growing promotion of local agriculture. Aided by the recently enacted farm brewery legislation, craft brewers in New York State have helped re-introduce hop cultivation to New York, spur grain production in parts of the state, and spin off ancillary industries such as Farmhouse Malt in Newark Valley. (In the near future I will feature two Finger Lakes breweries that source ingredients grown in-state: Abandon Brewing Company, and Hopshire Farm and Brewery).

Now back to that pesky fish bladder in my beer. Food Babe’s startling revelation is doubly skewed, first by suggesting that all that ground up fish bladder is sitting there in your beer holding up Guinness’ famously resilient foam, and second by implying – via association with GMOs and high-fructose corn syrup – that isinglass is somehow bad for you. (Again, point taken on the ambiguity of labeling, especially if you’re vegetarian, vegan, or among those who have an allergic reaction to isinglass.) But isinglass is a fining agent, which means it doesn’t stay in suspension in the liquid; the amount of it that makes it into your glass is miniscule, if it even makes it in there at all.

Originally manufactured from sturgeon and later from cod, hake, and catfish, this dried and treated bit of fish innards has a long history in beer, mead, and wine production. Writing about porters in 1760, brewer Obidah Poundage looks back at the intervening years since porter’s 1722 inception and lauds the advances made since then:

“I well remember for many years it was not expected, nor was it thought possible [for porter] to be made fine and bright, and four and five months was deemed to be sufficient age for it to be drunk at. The improvement of transparency has since been added to it by means of more and better workmanship, better malt, better hops and the use of isinglass.” (Daniels, Designing Great Beers, 264).

Isinglass and other fining agents such as gelatin, carrageenen, and even egg white yield a clear glass of beer, wine, or mead by bonding with proteins, tannins, yeast cells, and other compounds. Fining agents attract these compounds, which contribute to a cloudy haze that some find unappealing, causing the compounds to precipitate to the bottom of the fermentation vessel or bright tank.

Most of your favourite alcoholic beverages, be they beer, wine, or mead, will clear with enough time. But time adds up in the form of storage space and lagering capacity. Many larger craft breweries will filter their beer or run it through a centrifuge, but these pieces of equipment are usually beyond the means of smaller breweries just starting out.

Among the smaller craft brewers that I have polled – an admittedly very small sample, since I’ve been polling for less than forty-eight hours now – kettle additions of carrageenan are common. One brewer with a long résumé noted that, in his experience, nearly all breweries add finings of some sort to the kettle. Another brewer pointed to his brewery’s selection of a yeast strain that ferments quickly and efficiently, leaving the beer clear. Some beer styles like IPA throw a mild haze from the hops, but many brewers eschew the fining or filtering of beers post-fermentation so as not to strip the beer of flavour and aroma.

So there you have it, fellow imbibers. That clear glass of wine or beer you’re drinking is quite possibly the result of a fining agent used at some point in the process.

Bottoms up.

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I’d like to thank the brewers and beer writers who shared their knowledge with me on short notice.

Further Reading:

Alan Davidson, The Penguin Companion to Food (Penguin, 2002).

Harold McGee, On Food and Cooking: The Science and Lore of the Kitchen (Scribner, 2004).

Jancis Robinson (ed.), The Oxford Companion to Wine (Oxford UP, 1994).

Ken Schramm, The Compleat Meadmaker (Brewers Publications, 2003).

Ray Daniels, Designing Great Beers: The Ultimate Guide to Brewing Classic Beer Styles (Brewers Publications, 2000).