I rebottled a couple weeks later. After a couple of months of bottle conditioning, I tried a couple and found them to be more vinegar then hard cider. They are not yet fully vinegar, you could drink one but it definitely has a vinegar sour taste. Instead of dumping all this, I'm wondering what I can do to finish it and use it as a cider vinegar? Should I transfer back to fermentation buckets and add some more sugar and yeast to finish it? I do a lot of pickling and that is what I would use it for. Is there a low cost way that I can assure that the acidity is at least 5%?

Just give it some more fermentation time - likely a couple of months before all the sugar you added is used up in the process - and it will go to vinegar all on its own. No need to add anything. A pH meter would be the only reliable test for pH and unfortunately they aren't cheap.

Dave

Would the old litmus papers like you used in Chemistry class work for checking the acidity?

I did some further checking in some old books I have and one mentioned that one way to increase the strength of a homemade vinegar was to put it in the freezer and then remove any ice that forms (aka remove the water from the vinegar). Sounds like this would increase the acidity also. Anyone agree?

Another book said that a good policy is to not dilute a brine for pickling with water (as most current recipes call for) when using homemade vinegar and you should be fine. Any thoughts on this?

Yeah you can increase the strength a bit by freezing - an old method we used to do back when I was a youngin' - but it really doesn't separate out much water - it's more of a skim ice effect. Not worth the trouble to me and it's honestly not necessary as 5% is plenty strong enough.

Diluting the brine with water is just an option for taste as many don't like the strong vinegar flavor. No more than a 50:50 ratio is approved. You can always use straight vinegar if you wish and many do and if using stronger than 5% you may find you want some water in it. ;)

Dave

You shouldn't need to add yeast. You may want to add sugar and ferment it more. More alcohol gives more vinegar. 9% alcohol is about where stuff destined to be vinegar should be.
The sugars you use leave residual sugars the yeast can't ferment. Beano may break those down to give you a drier wine, you don't want a sweet vinegar.

The doubling of the yeast was not foolishness. Overpitching may change subtle flavors but the yeast doesn't start really working until it reaches critical mass (stuff it does getting to critical mass causes subtle flavors) and critical mass is a lot more than anyone would pitch. I pitch 5 gallon packs into 1 gallon batches all the time.
Underpitching opens the door for contaminations.

IMO you need glass carboys for secondary and tertiary fermenters, buckets and only using primaries are barely OK for basic ales. Reading between your lines it sounds like you were trying to treat the cider as ale, it's a wine - fruit juice and wine yeast. I just now bottled my apple wine. It is strong wine so it required more aging than cider but it sounds like you rushed to bottle.

Apple harvest time to Thanksgiving is still actively fermenting. All cider does not turn to vinegar, contaminated cider does.

I'm curious why you aren't asking on a brewing forum or at the brew store. I don't have a problem with the question, I rarely come to this forum. Just wondering since this was with bought cider and you obviously have brewing supplies and some experience. A good brewing forum will increase your knowledge and results greatly.

I meant a dedicated brewing forum. I haven't been on one in many years, the last one I was on was great until they decided to stop trolls by posting everyone's IP# and since I had a static IP# there was no way I was going to continue posting. Otherwise I'd have one to recommend.

You learn a lot and get a lot of recipe ideas (come to think of it that's where I learned about Beano to convert unfermentables). You just need a well populated forum so the crackpot ideas go up for peer review. Any well populated brewing forum should have people that know about vinegar too.

This year, I started fermentation in a large mouth 5 gallon tub. It came with a lid and a hole in which you put the bung and air lock.

Use the champagne yeast, not brewer's yeast or baker's yeast as this will increase the alcohol content.

Cider only takes about 2 weeks to get done - some people keep wine for 30 or 60 days.

In the first few days, you'll see "head" and bubbles, you will also see the yeast in suspension.

After a week, the bubbles will disappear but the yeast is still there.

I tried drinking it - and it gave me a pretty bad hang over - the reason is that the organic products in suspension give off trace quantities of methanol.

After a week more, the yeast will die and fall to bottom and the cider will clarify. You won't see the yeast in suspension.

Now it's done and ready for bottling.

I tried drinking it again - and no hangover.

The taste is not quite cider - more like white wine.

---

Regarding your question - you can add the sugar and the yeast.

If the vinegar is not "strong" enough as a pickling agent - then the yeast will continue to ferment.

If it is strong enough - then the yeast will not - which means it is a strong enough pickling agent.

However, be sure to add champagne yeast - as that can tolerate the highest alcohol content and acidity - I believe around 18%.

Also, you can just taste the vinegar and compare it to another product with a published acetic acid content of 5%.

Is it more or less sour - if it is more sour - it should have higher vinegar concentration.

It sounds to me like you vinegar is still oxidizing. You have to stir the vinegar and keep it open to air to allow oxygen to interact with the alcohol.

If it is unstirred, in a large barrel it can take six months, with an automatic stirrer it could take a two or three weeks.

The more surface area that is exposed to air and the frequent agitation will reduce the time to complete the process.

This year, I started fermentation in a large mouth 5 gallon tub. It came with a lid and a hole in which you put the bung and air lock.

Use the champagne yeast, not brewer's yeast or baker's yeast as this will increase the alcohol content.

Cider only takes about 2 weeks to get done - some people keep wine for 30 or 60 days.

In the first few days, you'll see "head" and bubbles, you will also see the yeast in suspension.

After a week, the bubbles will disappear but the yeast is still there.

I tried drinking it - and it gave me a pretty bad hang over - the reason is that the organic products in suspension give off trace quantities of methanol.

After a week more, the yeast will die and fall to bottom and the cider will clarify. You won't see the yeast in suspension.

Now it's done and ready for bottling.

I tried drinking it again - and no hangover.

The taste is not quite cider - more like white wine.

---

Regarding your question - you can add the sugar and the yeast.

If the vinegar is not "strong" enough as a pickling agent - then the yeast will continue to ferment.

If it is strong enough - then the yeast will not - which means it is a strong enough pickling agent.

However, be sure to add champagne yeast - as that can tolerate the highest alcohol content and acidity - I believe around 18%.

Also, you can just taste the vinegar and compare it to another product with a published acetic acid content of 5%.

Is it more or less sour - if it is more sour - it should have higher vinegar concentration.

It sounds to me like you vinegar is still oxidizing. You have to stir the vinegar and keep it open to air to allow oxygen to interact with the alcohol.

If it is unstirred, in a large barrel it can take six months, with an automatic stirrer it could take a two or three weeks.

The more surface area that is exposed to air and the frequent agitation will reduce the time to complete the process.

I have made wine, from grapes and grape juice. The process is just how John (OP) started:

-- add wine yeast to the juice (in a food grade bucket)stir it: You will see foaming. keep stirring. (If you are not too technical about it, you can even use bread yeast)

WHAT IS GOING ON?
The yeasts are digesting the sugar in the solution and the bi products are: ALCOHOL and CO2.
They (yeasts) will continue as long as there is sugar. Also, in the beginning and later, they multiply. So they will be there unless and until you kill them.

When you add honey, they will start the party, digesting the sugar from honey , making more alcohol and more CO2.

You might get to a point that there is some residual amount of sugar left and the yeasts are not active anymore(lazy) but they are there.

WHERE DOES THE VINEGAR COME FROM ?:

Both the yeasts and vinegar making bacteria exist on the fruits and perhaps in the air. You can make wine without yeast but it will take much longer time to get it stared. That is how somebody discovered the first wine, the first vinegar.
Now, as the yeasts make alcohol, from sugar, the vinegar bacteria make ACETIC ACID from alcohol. But in order to do that they need air, more specifically OXYGEN.
So if the wine making process is flawed, the vinegar bacteria will take the alcohol that the yeasts are making and produce ACETIC ACID. Vinegar is a french word meaning SOUR WINE.

How Do You Make Hard Cider ?
I have not done it but logic says that you GOT TO stop the fermentation process at some precise time, either by killing the yeasts or by refrigeration. So that you have some alcohol and the cider is still sweet.
If I was going to do it, I would kill the yeast. They have stuff in wine making stores for this purpose. An that is how the make FRUITY wine, KILL the yeast first then add honey or fruit juice.