Vinegar is resistant to spoilage but not impervious to it. If you think about it, vinegar is a fermented product, so yeasts and molds can occur in vinegar mixtures. Wine vinegars and rice vinegars are especially susceptible because they contain proteins which make good hosts for bacteria.

It may be there was some undetected mold in the strawberries or, because berries are difficult to clean sufficiently, there might have been surface yeast.

I'd discard both jars of the strawberry. One is fermenting and the other may have yeast on the surface, but it could equally well be something more harmful. I think your instincts are good.

The Extension services have this to say about vinegars:
If flavored vinegar molds or shows signs of fermentation such as bubbling, cloudiness or sliminess, it should be discarded without tasting.

Carol

Thank you Carol. That makes me very sad, but ... so it goes. At least the raspberry seems to be okay (and can I say it again? It smells fabulous!)

I was looking forward to spinach salads with strawberry vinegar dressing during the winter, but I guess that will have to be another year.

Thanks again,
Ann

I agree with Carol, I'd dump that other jar of vinegar, even if it's only slightly suspect.

There's always next year and now something to look forward to!

Annie

I know it's frustrating. Now I sterilize everything and heat the vinegar before using. I used to skip those steps (It's NCHFP "legal" to use unheated vinegar), but after I saw little fuzzies growing in my tarragon vinegar I decided to be much more meticulous. Part of the issue for me is I was using Japanese rice wine vinegar. It's perfect for berries and delicate herbs, but with the proteins and lower acidity, it's also much more suscetible to "invaders."

Carol

I did not heat the vinegar. I used the "Gourmet Vinegars" by Marsha Peters Johnson book - which I thought had been approved by people here - and it did not say to heat the vinegar. I have since read on several sites to do so, so next year I will. I also did not sterilize the jars but simply rinsed well with really hot water. Next year I will sterilize.

I tossed both jars of strawberry and will watch the raspberry closely for any disturbing changes.

I think next year I may have to do some herb vinegars.

Thanks again,
Ann

There's nothing wrong with "Gourmet Vinegars" per se. (I think I have that book around here somewhere.) And heating of the vinegar is not required.

It's one of those "odds" things. Odds are you aren't going to run into problems. Some people don't like to heat the vinegar because it speeds up the steeping process. They prefer it be longer and slower because they feel the flavors that develop are more intense and complex. It's akin to bread. You can go fast or slow. Each has its advantages.

As a compromise I've chosen to go with Carol Costenbader's method. As per the NCHFP, jars are sterilized. But while the NCHFP heats the vinegar to 190 or 195, Costenbader heats to 110, cools a bit and then uses.

Even then Costenbader says 110 is too hard on fruit. Personally, I've not heated any vinegar for berry infusions (I do for others) and I've been OK so far. But I am aware I have increased the risk of some jars not turning out. Some day I could easily end up where you are.

One tip from Costenbader. She does a double infusion, steeping the fruit as usual. After a few weeks, when all the flavor has been extracted, she strains it out and adds fresh fruit. You can do additional steepings if you'd like a more intense flavor. I've gotten some really terrific raspberry vinegar that way.

Also, when the vinegar is done and strained, she heats it to a simmer before bottling, skimming any foam that may appear. During the simmer a bit of sugar or honey can be added if desired. I've been adding just a tad of honey to fruit vinegars and really like the result. Cool and then bottle.

A very pretty presentation with the narrow-neck bottles is to cork and then dip the cork and bottle top in paraffin.

Carol