A new Smithsonian article has discovered Guinness Beer's use of isinglass, a technique that Guinness Beer has confirmed that it does to the Huffington Post, and even declared "Guinness Black Lager is not suitable for vegetarians."

Isinglass involves mixing the collagen of fish into beer. The collagen usually comes from non-kosher fish (the most common is the non-kosher sturgeon). According to the article:

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 it’s own, isinglass speeds up the process and doesn’t affect the final flavor of the beer once removed.

This process sounds very similar to using animal rennet to produce cheese. Now that we know of this process, is Guinness Beer still kosher?

Even if this non-kosher substance is less than 1 in 60 of the rest of the beer, doesn't its essential role to speed up and filter the beer-making process make it a vital ingredient, and thus batel b'shishim does not apply?

Many kosher agencies have previously accepted Guinness to be kosher. For example, Star-K specifies "All unflavored Heineken, Guinness, and Corona" are kosher. Regarding the issue of isinglass, the CRC notes:

Nodah B’yedhudah YD 1:26 rules that this does not pose a kashrus concern, and one of his reasons is that such a miniscule amount of isinglass remains in the beer that it is batel (nullified). [In this case there is no concern of bitul issur l’chatchilah – intentionally diluting non-kosher into kosher – because the isinglass is put in with the specific intention of removing it.] Some hashgachos rely on this line of reasoning and others hold that items which are certified as kosher should meet a higher standard and not contain any non-kosher components.

Nowadays, most beer companies do not use isinglass and instead use other methods to filter the beer.

Now that we know a major beer company uses isinglass, which authorities maintain that it wouldn't be kosher?

  • It seems from the question that those who held that it was not a problem when the Star K were asked would still say the same, and those who didn't rely on the kula still wouldn't. It is comforting to know that what is new to the smithsonian was known to the mashgichim already.
    – rosends
    Mar 15, 2013 at 13:00
  • 1
    Not everyone agrees that sturgeon isn't kosher
    – Double AA
    Mar 15, 2013 at 13:35
  • Isinglass isn't added for flavor, rather to process things. By the way, many other English and Irish beers use the same process. When I was vegetarian, I abstained from all Isle beers except Sam Smith. Mar 15, 2013 at 15:02
  • BTW this isn't a newly discovered issue. I contacted Guinness 3 years ago asking them what species of fish they use for the isinglass and they refused to answer me. But they did confirm that they use animal products and that a vegan should not drink it.
    – Ariel
    Mar 15, 2013 at 19:54
  • mentalfloss.com/article/70680/… -- Changes to Guinness process, will stop using fish
    – Menachem
    Nov 3, 2015 at 22:38

1 Answer 1


I asked this specific question of the Kof-K many years ago. They indicated that it is not a problem.

I called them on the phone, so I have no documentation, however, they referred to the Nodah B'yehudah. The isinglas and sediment is never intended to stay in the final product and is removed. The answer was very quick, with no need for research. It struck me that it was well understood and standard policy. Comparing this to the comments above from the CRC and Star-K, it strickes me that this is really a halachic non-issue,


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