How to tell if my ancient vinegar mother is good

Hello, I'm new to the group! Found it while googling how to determine the health of the vinegar I just inherited. The issue I'm running into is that I can't see or easily remove the mother.

Backstory:
I have a large ceramic jug of wine vinegar that I just inherited. The mouth of the jug is just big enough to insert a baster in to remove the vinegar. I'm the fourth generation to own it, and it may or may not have come over on a boat from Italy in 1920. The exact history is as murky as the vinegar vat. It's been producing exquisite red wine vinegar for as long as I can remember, and I've been given the simple instructions the family has always used to keep her producing: pour in a bottle of cheap red wine, wait a couple weeks, use a baster to fill a clean bottle with vinegar, repeat; keep a rag shoved into the mouth of the jug like a cork. Recently my aunt (who just gave me the jug) says the vinegar has been tasting a bit different, maybe less fermented, and she hasn't been able to find answers as to why. I'd like to keep this vinegar going strong as long as possible, and obviously would not like to make my family sick with bad vinegar, but how do I know if it's healthy if I can't see inside the jug or remove the mother to check? Any help appreciated!

Wow, what an interesting inheritance! I wonder if perhaps the type of wine your aunt used is an issue, some wines have a lot of sulphites etc used as preservatives which might affect the fermentation. Also, during winter, a low temperature could slow down the fermentation meaning the vinegar seems less "vinegary".

I'm pretty sure if the vinegar was not okay to consume you would notice -- it would smell or taste off. The serious nasties that don't necessarily affect the taste or smell like botulism shouldn't be able to grow in vinegar or in an open bottle. They need a low acid, low oxygen environment. If you are concerned, boiling the vinegar for ten minutes before consuming it should be enough to make it safe for most people apart from young babies or anyone with very low immunity.

I'm not a fermentation expert, however!

Jane Mulberry wrote:Wow, what an interesting inheritance! I wonder if perhaps the type of wine your aunt used is an issue, some wines have a lot of sulphites etc used as preservatives which might affect the fermentation. Also, during winter, a low temperature could slow down the fermentation meaning the vinegar seems less "vinegary".

I'm pretty sure if the vinegar was not okay to consume you would notice -- it would smell or taste off. The serious nasties that don't necessarily affect the taste or smell like botulism shouldn't be able to grow in vinegar or in an open bottle. They need a low acid, low oxygen environment. If you are concerned, boiling the vinegar for ten minutes before consuming it should be enough to make it safe for most people apart from young babies or anyone with very low immunity.

Thank you, Jane! It smells delightfully vinegary. Very strong and just like I remember it smelling when I was a kid!
So in your opinion if it smells and tastes like it should, it's safe to continue treating it as we have been? I don't need to remove part of the mother or anything? I've done limited fermentation - made kombucha from scratch once or twice, lactofermented some veggies, made a failed attempt at starting sourdough from scratch. The only thing that makes me nervous about this is not being able to see anything inside the jar!

Mother requires air in order to convert wine to vinegar. Did the rag, or way it's applied change recently?

I would think that routine maintenance of the culture would involve removing most of the mother from the jug from time to time.

Joseph Lofthouse wrote:Mother requires air in order to convert wine to vinegar. Did the rag, or way it's applied change recently?

I would think that routine maintenance of the culture would involve removing most of the mother from the jug from time to time.

I do think the rag may have been too much of an obstruction, from what I'm reading. I took it out of the opening and just draped it over.

Regular remove makes sense to me too from what I know of fermentation, but according to family tradition that's never been done as far as we know, and it's always made great vinegar... I don't even know how that would be possible given the small size of the opening. Any idea what could go wrong if it's not removed occasionally?

I wondered if the rag had been stuffed in too tight. As Joseph said, making wine into vinegar requires air!

I think this might sound kind of critical, but in your experience, is the taste different? have you compared it with other red wine vinegar to figure out what exactly the issue is? one person's taste perception can be kind of subjective... if this were me i think i'd want to have a bit more data!
(i have at this very moment a jar of red wine vinegar going out on my porch with a bottle of wine that was too nasty to drink. i agree that you want to be stopping flies--not air-- from getting in.)
Inquiring mind wants to know what happens with the mother-- when you remove the wine, do you strain it out (and throw it back in)? is the mother always small/runny, or does it ever get large and floaty (and potentially host mold)? I'm thinking of my experience with booch and while I love a family heirloom and crockery, I think I would want to see what is going on in there!

An image of the Mother might help with a diagnosis.

Family heirloom vinegar mother, how cool is that! Mine is nowhere near so venerable, but perhaps my experience will help you. I've been keeping a homemade crabapple vinegar for some time with mother on top - it is exquisite. Or rather, it was...

The last time I removed some to use, I found it seemed almost bland, or watery.  It was enough of a change that I did not use it and relegated it to the back of my mind and pantry. Then, while listening to a podcast featuring fermentation teacher Sandor Katz, he speaks about vinegar losing acidity when exposed to oxygen. In an open vessel, once the alcohol is gone (leaving vinegar) the acetobacter will consume the acetic acid it has just produced and the product will be degraded.

He recommends keeping your fermentation vessel full with minimal oxygen at all times, instead of taking some off the top to use as you need it. When you want vinegar you decant and fill smaller jars (preferably the sort with narrow necks, to the rim), keep those sealed until needed, and refresh your main fermentation vessel back to full. If there is visible air gap in your crock at times, this might be the issue.

Good luck, may your lovely mother live long and nourish future generations!