Another vinegar question popped up a few days ago.
Regan wanted to know whether all vinegars were vegan. Regan was concerned that some vinegars were derived from whey and that others were filtered with isinglass.
While we already addressed this question a while back, I realized that we did not discuss the filtering process.
As the original Is It Vegan Vinegar post states:
Vinegar comes in many varieties and is made by fermenting ethanol into aceyic acid. This starts with a plant base (grapes, apples, barley) which is then fermented or distilled into wine, beer or malt, and then further fermented to yield a vinegar. Vinegars can also be infused with fruits and herbs which enhance their flavor profiles. The only animal based exception I found is honey vinegar, which would not be vegan as honey is used as the flavoring agent. However, honey vinegar is fairly rare, at least here in the US and will likely be labeled specifically.I have never heard of or subsequently read about any vinegar that comes from whey.
When researching whether or not isinglass is used in filtering, it seems to me that while that is a method that can be used, it is not very popular. I took the liberty of contacting Heinz, a major manufacturer of many vinegars to see if they used isinglass. They did not:
June 28, 2011Dear Melissa,
Thank you for visiting our web site.
Heinz vinegar is not filtered through isinglass. It is considered suitable for vegetarians.
Thanks again for contacting us. We appreciate your interest.
Heinz Consumer Resource Center
Heinzconsumeraffairs@us.hjheinz.com
We certainly can’t speak for every vinegar manufacturer out there, but I feel confident with vinegar’s vegan status.

Interesting!
need to know all things vegan
The isinglass would be used for clearing the fermented brew of yeast & sugars, not sure if they would use it to clear the vinegar. So it could be used on the precursor to vinegar the beer, wine etc.
The question to Heinz should be are all their ingredients and processes vegan -i.e. they might be buying in ready made non-vegan beer and using it.
My underestanding is that vinegar eels (Turbatrix aceti) grow on pretty much all vinegar, and are killed and filtered out before bottling for commercial distribution. These are not microorganisms, they are visible to the naked eye.
I had never heard of this. From the reading I’ve seen, the bacteria and yeasts are filtered off BEFORE the eels show up, in modern vinegar production.