Isinglass By Nick Fisher

Isinglass

By Nick Fisher

Next time you look longingly into your pint of beer, spare a thought for fish. Your pint wouldn’t look like a pint of beer as we know it, if it wasn’t for the intervention of fish. The art of fine brewing owes a huge debt to fish, particularly for one unique ingredient: isinglass.

This bizarre-sounding stuff, was originally derived from the swim bladders of sturgeon, and its most common use was in brewing beer. Isinglass was added as part of the process of clearing the beer’s natural yeasty cloudiness. The clarifying method is also known as ‘fining’. Basically it helps make beer look like a transparent and appetizing beverage, instead of sick Spaniel whizz.

It seems outrageous and incongruous to me that anyone should ever mix cloudy beer with the deepest, darkest organs of a sturgeon. How did those two things ever get put together? Did some despondent brewer, depressed by the opaqueness of his ale, sit down and write a list of all the things he could possibly think of that might bring clarity to his brew? And if he did, how’d he ever come up with the sturgeon swim bladder? Why not just sturgeon head, or scales, or tail? Why go digging in such private places? What could possess anyone to go and stick dead sturgeon in a perfectly good (if slightly cloudy) barrel of beer? I don’t get it. Doesn’t make sense.

The accepted theory as to how isinglass was first discovered is by someone, back in ancient times when beer and wine were carried and stored in sewn-up animal skins, or fish bellies. One day, a cloudy wine was stored in a skin, and when it was poured out, it had miraculously cleared! Does anybody buy that?

Anyway, we’ll never know the whole murky truth. To extract isinglass, which is essentially made up predominantly of collagen, from a fish swimbladder, it needs to be dissolved in organic acids. Once isinglass is added to the brewed beer, it works like floating magnets: isinglass is made up of positive molecules which latch on to the negative molecules of the cloudy yeast, creating heavier molecules that sink to the bottom of the barrel. Then the cleared or ‘fined’ beer can be siphoned off the top of the barrel leaving all the gunk at the bottom.

Isinglass was so important to the brewing trade in the 19th century that brewers would go to great lengths to secure a continuous supply. Most isinglass came from Russia, because of the ongoing sturgeon harvest and trade connected with caviar and sturgeon products. But the advent of the Napoleonic Wars made trade through Europe to Russia increasingly difficult. As a result, the price of isinglass rose exponentially. Brewers who desired a premium beer product, one they could achieve top money for, knew they would only beat the competition if their beer was clear. Sure, clear beer can be achieved without isinglass, eventually, but it takes much longer for it to clear naturally. Isinglass accelerates the fining process which allows the brewer to brew and sell beer, faster.

So when William Murdock, one of the most celebrated engineers of the Industrial Revolution, invented a method of extracting precious isinglass from a much more easily available fish: cod, the brewing industry got very excited indeed. Isinglass extracted from sturgeon was rocketing in price to a brewer-choking 25 shillings a pound. But cod-derived isinglass was a fraction of the cost. The cost-saving was so substantial that the Committee of London Brewers clubbed together and paid Murdock a staggering two thousand quid for the right to use his invention to extract isinglass from British fish.

Beer fining wasn’t the only important use for isinglass, confectioners and bakers used it for making jellies, blancmanges and high quality sweetmeats. Later, when the production of much cheaper gelatin was developed, isinglass was used less often in cooking, but it always had a vital role to play both in art and religion.

The purest form of fish glue was produced by using isinglass extracted from the membrane of the swimbladder from sturgeon. Fish glue could be made simply from boiling down fish bones and skin, but the finest and most transparent adhesive was created from isinglass. The Egyptians were the first to use isinglass as a medium to bind colours for decorative painting, and to adorn royal tombs. Then, the mediaeval monks in the monasteries of Italy and Germany developed techniques for using isinglass in the painting of illuminated manuscripts. The fish-based glue could be made into such a fine and pure gum that it soon became the only medium to use with gold, for the gilding of illustrated illuminated manuscripts.

The development of isinglass and fish glue fixatives continued right up until the 20th century when they were phased out in favour of cellulose-based, chemically-produced glues. But without fish and fish-extracted products, most of the frescos of Renaissance Italy and the panel paintings of the Dutch Masters like Van Dyck, would have crumbled away to dust. In many ways, fish held the whole fabric of religious art together.

Even the brewing industry hasn’t completely chemicalised its processes; some breweries still use isinglass for the production of cask-conditioned, real ale beers. Although some vegetarians and vegans object, and won’t drink beers fined with fish or animal products. There is an alternative though: Irish Moss—a type of red algae which is introduced hot, at the beginning of the brewing process, rather than the end as with isinglass.

But asking you to be thankful to an algae for the beautiful beer in your glass just doesn’t feel right. Fish are what we have to thank for good, clear, natural beer. Fish.