Fermentation problem

[Matt Wilson]

Hello everyone,

I am having trouble with my primary fermentation of the fresh raw cider I bought from the apple orchard near me.  This is my second season of cider making and have had no trouble with the process with the my own or my neighbor’s apples.

Through my 3 different attempts in 3 different vessels, each with a potassium metabisulphate treatment and champagne yeast inoculation, the cider seems to turn to vinegar even if I can get the fermentation going. 

The orchard claims that the juice was pressed on 10/28 and I started the first batch on 10/29 while freezing the rest. 

I’m sure I am showing my lack of understanding and experience, but would anyone be able to help me troubleshoot this?

Was the fresh cider let sit at the Orchard somehow? Was the fresh cider tainted from the beginning somehow?

I just started a final batch with one and a half gallons of fresh juice that I pressed and 1/2 gallon of juice from this apple orchard. Is this batch likely to spoil as well?

I would like to understand what went wrong before I make another investment in buying fresh cider.

Thank you so much for your help,

Matt

[Albert Johnson]

Hi Matt, 

How much headspace was in your fermentation vessel? This is the most likely cause of any acetification. Your vessel should be, in my opinion, as full as possible (95% or more). 

What was the temperature you stored the juice at? 

Cheers

Albert 

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[Matt Wilson]

Thanks for your help Albert,

I have been doing my primary fermentations in an open container covered by cloth watching closely to see when the must is starting to be exposed to the air so far is usually a week or two for my successful batches.  I don't think its an head space issue because it seems like I can't actually get the fermentation started....the normal foam doesn't form.  Its more like bubbles or chunks. To me it seems like the vinegar was already forming when I got the juice.  The juice hasn't fermented yet it tastes like vinegar.  Is there something else going on here? 

The fresh juice was either immediately attempted to ferment or frozen.  My basement is about 60F in MN (but semi heated).

Thanks again,

[Matt Moser Miller]

Hey Matt,

I’m not sure what you mean by “open container covered by cloth;” are we talking something with vertical walls all the way up (like a bucket/plastic fermenter), or something that narrows at the mouth (like a jug/demijohn)?

Either way, I don’t see any reason to be fermenting it with that much ready access to oxygen/air/microbes, especially given how small a volume you seem to be working with. Airlocks are quite cheap, and allow you to build a layer of CO2 atop your fermentation/exclude air exposure more effectively than open under cloth (which…I’ve only read as instructions specifically FOR making vinegar?). Also, if it’s in a straight-walled container: at those low volumes, that’s a much greater surface/air exposure than something with a lower surface-to-volume ratio.

Now, all of that said: if you’re getting fresh juice from a spigot/spout in a cider mill, it’s entirely possible that they haven’t cleaned their lines or fittings properly; if those plastic nozzles they filled from have been sitting with juice in their crevices, at room temp, for days, there’s every likelihood they’re culturing acetobacter that touches every drop on the way out. I’d need to know more about their set up to say with any more certainty, but…

Matt Moser Miller

Pealer Mill Orchard & Cidery 

Sent from my iPhone

On Jan 19, 2026, at 9:57 PM, Matt Wilson <mwhorn...@gmail.com> wrote:

Thanks for your help Albert,

To view this discussion, visit https://groups.google.com/d/msgid/cider-workshop/48cb54fa-c6aa-41d8-bda8-dcfbc07554c2n%40googlegroups.com.

[gareth chapman]

Well there's your issue if it has been open and exposed to the air since October at 60 degrees then you can be pretty sure that it has gone right through the fermentation process and you now have vinegar. Just because you think you didn't see any fermentation doesn't mean it didn't happen, with a champagne yeast at that temperature the fermentation could have finished after a week.

[Matt Wilson]

 Thanks everyone for you help and patience,

I realized that is should be more detailed in what I am relating to you if I want help trouble shooting this.

The date on the buckets from the Orchard said 10/27.  I believe I pitched the yeast on batch one the day I picked it up.

Batch number one pitched yeast on 11/1 in a bucket covered by cloth with the lid loosely attached. (this is how i have done my primary fermentations for all of my own apples without a problem...usually moving it to secondary after 7-10 days)  Did not add any potassium med by sulfate. Had been checking every few days to see if the surface of the must had started to clear, but it never did. 1st racking 11/29.  The airlocks were not bubbling at that point. And it tasted very vinegary when I checked them soon after. They still had some residual sweetness.

Batch number two fermented in a glass container with a cloth and a glass lid set on top. Pitched November 3 and first wrecking was November 14. On December 26, I bottled it but it had a definite vinegar flavor that seems to have only grown stronger when I tried one of the bottles a few days ago.

Batch number three was frozen from early November through January 12. Once it was fully thawed on January 14, I pitched champagne East and 1/2 tablespoon of potassium made by sulfate and 1 tablespoon of pectinase into a bucket with a lid attached and and airlock in the lid. The next day 24 hours later, I pitched champagne yeast. The surface remains broken without foam and instead it had  chunks floating. Two days later, I tried another champagne yeast inoculation, which was fresh cider warmed up on the stove to 105 and pitched. The next morning there was a very nice foam and so I pitched that into the must. Still no bubbling through the airlock.  

Batch number four is 2 gallons of fresh cider one and a half from my tree and half from the Orchard. Is there anything I can do to keep this one from spoiling?

My other question is, what should I do to juice that I did not produce to avoid this spoilage?  Pasteurize?  Is there something else potentially causing the spoilage?  IS there nay reason we shouldn't use the vinegary cider cooking etc.?

Thanks again for your help,

Matt

[Thomas Christie]

I think it’s possible that the flavor of this juice when fermented dry is more acidic than you are used to, and this is what you are thinking is vinegar character. Actually producing vinegar usually takes a fair bit of time, even when inoculating with acetobacter and regularly aerating to feed the bacteria more oxygen. You say your first batch tasted quite vinegary after one month, but at that point your cider is likely still more or less saturated with CO2 and I just can’t imagine there would have been opportunity for significant acetic acid production by acetobacter.

I would also suggest getting yourself a hydrometer to monitor your fermentations. If you do have some sort of spoilage going on I would guess part of the cause would be that your yeast are for whatever reason not as viable as they should be, which is possibly allowing room for spoilage organisms to get a foothold. The best way to check tbis is by monitoring your fermentation through change in gravity, just going by foam and airlock bubbles is a bit of a crapshoot.

-Tom 

To view this discussion, visit https://groups.google.com/d/msgid/cider-workshop/e6de4be2-2684-4cd1-af95-8824af7f073dn%40googlegroups.com.

[Matt Wilson]

Thanks Tom,

I did measure the SG of the first batch and it came in at just above 1.000.  I will monitor the current two (3 and 4) 

It would make sense what you say about the cider being high in acid because I don't really know what kinds of apples are in the juice.  The Orchard has a lot of Haralson and Cortland apples.

Is there another spoilage that would bring out a vinegary flavor?

Shouldn't the Potassium Metabisulfate take care of those issues?

On Batch number two, the bottled cider has what looks like a mother forming on top the the cider.  Batch number one definitely has a mother.  

Thanks for helping me work through this,

Matt

[Thomas Christie]

There are other sources of VA (vinegary flavor). Other bacteria such as gluconobacter and various lactic acid bacteria can do this, as can brettanomyces and even saccharomyces under certain conditions. For most of these you need oxygen or a lack of mallic acid, so I would still be a little confused by the timeline of noticing this taste after just a month when you’ve also inoculated with yeast. 

Treating with sulfite should prevent these issues (except for perhaps brettanomyces), however in order to accurately dose you need to dose relative to pH, and at relatively high pH (above 3.9 or so) sulfite ceases to be effective as an antimicrobial even with very large doses.

To view this discussion, visit https://groups.google.com/d/msgid/cider-workshop/db667b79-32a6-4216-8059-fbf5b71fe037n%40googlegroups.com.

[Matt Wilson]

The above is batch 1 

This is batch two:

Thanks again!

Matt

[Mark Fitzsimmons]

Matt,

The bacteria which is spoiling your batches tends to be ubiquitous (it is found everywhere floating in the air, especially in kitchens, and especially kitchens with things like vinegar, fruit, yogurt, etc.). It also requires air to continue its metabolism. Your open fermentation method is the most likely culprit, but you can also benefit from proper healthy yeast starting protocol (rehydrate at 104 F/40 C, using a rehydration nutrient like go-ferm at 1:20 ratio by weight with water). Yeast only needs air in the beginning lag phase, when it is rapidly multiplying the number of yeast cells. Pitching a much higher number of yeast cells can improve your chances, however, protecting the juice from all air after the initial day is also very important: the yeast don't need the air, and the bacteria cannot live without it. Higher pitch rate can be done two ways: use more dry yeast , or get your starter going for a day with a smaller bottle of juice before adding it to the main fermenter. Since you are doing small batches of 1-2 gallons, using a packet designed for 5-6 gallons is a good over pitch I think you will have better luck if you do these things. Your open fermentation vessel method worked a couple times by luck. close it up with an airlock. If you want shorter lag times, you can bubble air through for an hour after pitching, or splash it around a while at that time, but really, put an airlock on it.

[Mark Fitzsimmons]

also to directly answer your question: yes the cider from your local mill could be infected with large amounts of acetobacter and a host of others, more so than your own apples, so even with healthy sulfite dosing, it could be your own juice is just cleaner than the commercial juice. Closed fermentation and over-pitching yeast colonies (look for yeasts with high "Kill Factor" which is one of the traits advertised) are still the answers to fix this problem. 

[Matt Wilson]

Thank you to everyone who chimed in to help me try to figure out what is spoiling my batches.  I see now that the pics I posted didn't upload.  Last question, ( I promise)...the batch that has been bottled (batch 2) did not seem to have much of the vinegary taste but started to form grayish white filmy chunks on the surface of the cider.  Does that still point towards acetobacter infection?  I thought that needed to be exposed to oxygen?

On my way to buy a 5 gal. carboy for my future primary vessel,

Matt