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?
