Isinglass removal from Guinness is welcome news

By Roger Protz

- Last updated on GMT

Isinglass removal from Guinness is welcome news

Related tags Isinglass Beer Brewing

Removing isinglass finings from Guinness is welcome news for many. Roger Protz explains why.

The news that Guinness is to stop using isinglass finings to clear its stout led to much media comment — some of it of a ribald nature. “Why do you need to clarify a beer that’s jet black?” was a typical comment while others complained it was being done to appease vegetarians.

If you hold a glass of Guinness to the light and rotate it, you will notice that it’s not completely black but has what brewers call a “ruby edge”. Look carefully, and the beer is perfectly clear.

The clarity of beer is easier to see with lighter coloured beers such as bitter and golden ale. Since the 19th century, when glass replaced pewter as the standard container for beer, drinkers have expected a crystal clear pint for their money.

That is where isinglass comes in. It’s made from the swim bladders of fish, usually such tropical varieties as catfish and drum fish. The bladders are boiled, turned into a viscous thick white liquid and poured into casks or kegs of beer before they leave the brewery.

A natural electro-static process takes place in which a positive charge in the isinglass attracts negative charges in the yeast and proteins in the beer. Yeast and protein cling to the isinglass, which drags them to the foot of the container.

Isinglass is mainly used in cask ale, which is not filtered. It’s less often used in keg beers, which are filtered to remove yeast though clearly some keg beers such as Guinness do use it.


Guinness’s decision has more to do with pleasing vegetarians than appeasing them. Britain is Guinness’s biggest market and between 7% and 11% of Brits are now vegetarian or vegan.

That means some six million people avoid eating meat or fish and don’t like the idea of fish bladders being used to clear beer.
Guinness is aware that the food chain Pret A Manger plans to convert some its shops to vegetarian and vegan offerings only and wants to give its stout the widest possible appeal.

I declare an interest: I am a vegetarian. I also drink a lot of cask beer: as editor of the Campaign for Real Ale’s Good Beer Guide, it would be rather odd if I didn’t drink the product I champion. I do so on the grounds that the sediment in a cask is below the level of the serving tap and it’s unlikely it will be drawn to the glass.

I’ve tasted some odd things in beer over the years, but never fish.


Nevertheless, I would much prefer it if fish bladders weren’t used in beer. I’m not alone. When I mentioned this to the managing director of a regional brewery a few weeks ago, she turned to her head brewer and asked: “Why in the 21st century are we still using isinglass?” He stroked his chin and replied: “Good question.”

There are answers to the question. Irish Moss can be used to clear beer, but I’m told it’s not as effective as isinglass and is used mainly by brewers during the copper stage of the brewing process, when the sweet extract or wort is boiled with hops.


But the amazing hop plant could come to the rescue.

As well as adding delightful aromas and flavours to beer and keeping it free from infection, it’s thought the plant could also be used as a clearing agent. Trials are being carried out and it seems that a mixture of fresh and used hops could be used in place of isinglass.

Guinness has yet to say what it will use instead of isinglass but it’s not alone in abandoning fish finings.

A growing number of British brewers are now making some or all of their beers suitable for vegetarians and vegans.

A new brewery called Boudicca has opened in Norfolk to make only vegan-friendly beers. The head brewer, Andy Mitchell, says the policy is not only about reaching out to drinkers who avoid meat and fish but also because he feels isinglass strips some of the flavour from beer.

His view is echoed by Justin Hawke, who runs the Moor Beer brewery in Bristol. Hawke doesn’t fine any of his beers. As his range includes several pale ales and IPAs, you might expect some consumer resistance to being served slightly cloudy beer.


But Hawke, who explains his thinking on labels and pump clips, says he has had no complaints, only a growing willingness to try full-flavoured beers that are
not completely free of sediment in the glass.

He is adamant that isinglass detracts from the flavour and character of beer. He has lived in Germany where drinkers are perfectly content to drink cloudy wheat beers labelled “mit hefe” — with yeast — and he thinks the concept will catch on and grow in Britain.

I hope so. I think swim bladders should remain attached to fish. They have a greater need of them than beer drinkers do.

Related topics Beer

Related news


Follow us

Pub Trade Guides

View more

The MA Lock In Podcast

Join us for a Lock In