Vinegar making smells like cheese

Hi everyone

I have two batches of vinegar fermenting away at the moment.  Both had a fly land in them, and subsequently saw a film of bacteria grow over the top.  The batch that smells ok was pure apple juice, and the other batch which was some apple cider (hard cider) smells of cheese.  I mean it really does pong.  I tried tasting some the other day and it sort of tasted vinegary.  Certainly didn't taste revolting.  I'm attaching images of the two batches.

So is it normal for fermenting vinegar to smell cheesy?

Thanks

Short answer is yes you get all sorts of funky smells fermenting apple juice to cider due to various reasons. As however your goal is vinegar dont worry about it.

Have you actually fermented the apple juice? Because if you have bought pasteurised apple juice and left it exposed to the air it will more than likely just go moldy.

It was raw apple juice I pressed myself from apples this autumn

It should be ok then.

Was the fly very small striped with red eyes? Is there now something slimy growing on the surface?

If so it's a fruit fly and has bought the vinegar making bacteria with it.  

Your process should go: Press juice or buy juice and add yeast  --> Let apple juice (sweet cider to Americans) ferment in an airlocked tank --> rack (hard) cider to new tank to remove sediment --> Add bacteria culture e.g from existing vinegar --> Expose to air (usually for atleast a few months)

I didn't look closely at the fly, but the fly that landed in the hard cider looked a little bigger, so i was wondering if it was a different fly that had brought a different bacteria.  Anyway, as you say, if this is perfectly normal I shall wait it out a few more weeks.  Just seems odd that the other batch with apple juice doesn't have that smell.  Well, I know there are a lot of different bacteria out there.  I wonder if another type took hold.  By the way, it's been probably 6 weeks now, both were really slow to get innoculated, and that film on the top is certainly not a "mother" yet.  Really thin film of bacteria.

It's interesting what you say about fermenting the juice in an airlock first.  I was questioning this in general with vinegar before.  It seems that some vinegars like wine vinegar is made from the alcoholic fermented product, and yet, at least in England, ACV is always made from neat apple juice.  I've never seen a recipe that says ferment it to hard cider first.    Same way malt vinegar isn't made from sprouted barley mash, but rather the alcoholic ale they produce first.
As far as I'm aware the only difference is that when you do it from the base sugar liquid e.g. apple juice in this case, the yeast and bacteria live in there smilutaneously, and as asoon as the yeast eats the sugars and turns it to alcohol, the acetobacter living alongside them then turn it into vinegar.  Whereas with wine vinegar, and the method you suggest, the human ferments to alcohol first, and then lets the acetobacter at it.  But the process is identical.  

So, what does it matter which way you do it, and why is red wine vinegar never made from grape juice?  This is why I did a batch of apple juice and cider vinegar so see if there was any difference.

You got me on my rant now!  

I haven't tried making vinegar directly from juices. I've made a lot of vinegar from wines. I don't see very many mothers form. I mostly see scums, if anything. So those scums in the original post look perfectly normal to me.

Jambo Reece wrote:I didn't look closely at the fly, but the fly that landed in the hard cider looked a little bigger, so i was wondering if it was a different fly that had brought a different bacteria.  Anyway, as you say, if this is perfectly normal I shall wait it out a few more weeks.  Just seems odd that the other batch with apple juice doesn't have that smell.  Well, I know there are a lot of different bacteria out there.  I wonder if another type took hold.  By the way, it's been probably 6 weeks now, both were really slow to get innoculated, and that film on the top is certainly not a "mother" yet.  Really thin film of bacteria.

It's interesting what you say about fermenting the juice in an airlock first.  I was questioning this in general with vinegar before.  It seems that some vinegars like wine vinegar is made from the alcoholic fermented product, and yet, at least in England, ACV is always made from neat apple juice.  I've never seen a recipe that says ferment it to hard cider first.    Same way malt vinegar isn't made from sprouted barley mash, but rather the alcoholic ale they produce first.
As far as I'm aware the only difference is that when you do it from the base sugar liquid e.g. apple juice in this case, the yeast and bacteria live in there smilutaneously, and as asoon as the yeast eats the sugars and turns it to alcohol, the acetobacter living alongside them then turn it into vinegar.  Whereas with wine vinegar, and the method you suggest, the human ferments to alcohol first, and then lets the acetobacter at it.  But the process is identical.  

So, what does it matter which way you do it, and why is red wine vinegar never made from grape juice?  This is why I did a batch of apple juice and cider vinegar so see if there was any difference.

You got me on my rant now!  

It might not make a difference a lot of the time but as an English cider maker I can honestly tell you I have never heard of anyone here doing it that way! Yes its made with neat apple juice but it is fermented fully first. A lot of that is to do with cider makers wanting an alcoholic product as opposed to vinegar. What happens usually is the less interesting cider or the tank someone left the lid off by accident is used for vinegar.

Serious issues are unlikely but if there is a stuck ferment it might not be obvious from the taste there is residual sugar or that the ph is low enough. These are easy to test and fix though.

I guess that due to the exponential growth rate of yeast and bacteria it might actually be faster doing it in stages anyway. It would be interesting to find out.


If the fly landed in the cider the alcohol will kill most pathogenic bacteria and the ph would make it inhospital to it too. What you have there looks like it could be a film yeast on the bottom pic, and random bits of yeast on the top.

If there is bacteria present it would be malolactic or acetobacteria.

How did you learn your process then henry jabel?
Was it in a book or from a friend?

If you google "making apple cider vinegar", every single link on the web shows them making it from apple juice directly, and not cider.

The irony here of course is that it's the cider one that is smelling cheesy

The way I read those on-line recipes, is that they are first making wine, and then converting the wine into vinegar.

I am highly suspicious of wine or vinegar making recipes that start out with instructions along the lines of "sterilize your equipment".... I ferment with natural yeasts and mothers, so whatever germs are on my equipment from the last batch seems good enough for me.

Jambo Reece wrote:How did you learn your process then henry jabel?
Was it in a book or from a friend?

If you google "making apple cider vinegar", every single link on the web shows them making it from apple juice directly, and not cider.

The irony here of course is that it's the cider one that is smelling cheesy

It was my job for a number of years way before people even started putting the word 'apple' unecessarily before cider vinegar

A lot of Amercians discovered cider vinegar before cider (awareness of it barely existed in the states less than 5 or so years ago) so maybe they didnt know you were meant to make the alcohol properly first?


Anyway I did your google test, these are the first two results for me and they are exactly how I described it:

http://www.earthclinic.com/remedies/how_to_make_apple_cider_vinegar.html

http://www.apple-cider-vinegar-benefits.com/homemade-apple-cider-vinegar.html


The cheesy smell will probably go in time beating some air into it will help.

Some random bacteria or mold must have taken hold as you can see from the photo. It really was ponging, and I sampled some from below the mold.  It tasted watery, so I know it has started to break down.  Just one of those things I guess.  

Thanks for those links, and if that is true in the States, then it must be a difference in our cider makers, because I can assure you there are plenty of Brits making it straight from the fruit juice.   Anyway, that's good to know.  I would imagine as you said it may well be faster to do it in a two stage process, and certainly is more controlled, and may make a more complete ferment.

But am I right in saying that in principle, it shouldn't make any difference whether you do a two stage or one step process?  Same sugars, same yeast, same bacteria, just done in a different order

Cheers

The chemical reaction that leads to producing vinegar is:

Sugar plus yeast ---> Alcohol
Alcohol plus mother plus oxygen ---> Vinegar

Lots of other chemical reactions are going on:

Organic chemicals plus micro-organisms ---> Mish-mash of compounds

In theory both the sugar to alcohol and alcohol to vinegar reactions can occur simultaneously. The yeast can work without oxygen, and the mother requires oxygen. In my practice I like to make alcohol first under anerobic conditions that are very suitable for the growth of yeast, and less suitable for the growth of other types of  micro-organisms. The created alcohol and lack of oxygen inhibits the growth of many types of micro-organisms. Then I separate out the yeast and micro-organisms that settle out with the yeast. After I have a good clean alcohol, that tastes good, then I create aerobic conditions that are very suitable for the growth of mother.  By having mother grow quickly, and under conditions that are very suitable for her, I believe that it inhibits the growth of other types of micro-organisms. I use a two stage process in an attempt to give each of the contributing micro-organisms their optimal conditions, and to attempt to minimize the growth of other micro-organisms.

Jambo Reece wrote:Some random bacteria or mold must have taken hold as you can see from the photo. It really was ponging, and I sampled some from below the mold.  It tasted watery, so I know it has started to break down.  Just one of those things I guess.  

Not trying to be argumentative Henry, I'm just inquisitive as to the difference. Thanks for those links, and if that is true in the States, then it must be a difference in our cider makers, because I can asure you there are plenty of Brits making it straight from the fruit juice.   Anyway, that's good to know.  I would imagine as you said it may well be faster to do it in a two stage process, and certainly is more controlled, and may make a more complete ferment.

But am I right in saying that in principle, it shouldn't make any difference whether you do a two stage or one step process?  Same sugars, same yeast, same bacteria, just done in a different order

Cheers

That looks like its spoilage bacteria so I would consider chucking away. If it is the one made from the cider I would guess that it had too much residual sugar / to high a ph. They wouldn't take hold like that in a fully fermented unpasteurised cider as the alcohol and low ph would make it too inhospitable.

By doing the two stage process it helps elimate the risk of it going wrong like joseph said. If you dont mind having a lot of sediment the only extra equipment and effort is a airlock which you can fit to any closed container with a drill and a grommet.

I am sure the British people making it in the one stage process wouldn't be doing it for a living as I can't see it going down well with the food hygiene inspectors. If they are selling via this process please tell them not do it this way because cider making here is curently regarded as a low risk food process (and enjoys comparatively little government monitoring) and the last thing I want is someone else getting sick because they are not minimising risk.

Thanks so much for all your help last year.  I still however seem to be struggling with the vinegar making.  Not sure why it's proving so difficult.  I thought you just left it exposed to air and voila!

Anyway, I managed to do a couple of batches without mold growth but the acidity is very low every time.

I fermented apple juice to cider with a strength of 6.14% which I calculated by measuring the specific gravity of the juice, and then the cider at the end of fermentation.

The cider was left exposed to air in a wide mouthed container in a bedroom at room temperature as seen in the photos above.

What tended to happen was that the cider started to smell and taste vinegary within a few days of innoculation, but would peak after 2 weeks, and any longer than that and it began to taste watery and less strong.  I had assumed this was the bacteria moving onto the next stage of breaking it back down into water and CO2.  Presumably you have to be quick, and catch it at this peak and seal it in an airtight container to stop this next step happening?

I measured the acidity using the titration method several times at what I thought was peak acidity and when I became weak and watery.  The problem is, at the peak it is only about 2%, and as it got weaker it dropped to 1.2%.  And by taste I would say this was about correct.  Even at peak, it tasted nothing like a 5% vinegar.

Just wondering if you've experienced this and had any ideas?  I don't really understand what is going on.

Thanks again guys

Here is much information on making vinegar.

Vinegar compilation