'Tis a puzzlement....

[Old Philosopher]

Q&A:
I'm just finishing two 4gal batches of apple wine. Without a lot of boring details, here's the deal:

Each batch started with 3 gal of pressed juice + 1 gal water. I brought the SG up to 1.100, added yeast nutrient and HC-1118 yeast. No starter, just pitched the yeast.
They got neglected for awhile, and one batch fermented dry (SG .990) in the primary in 12 days. The second batch was down to 1.010. I racked that one to a secondary carboy under an air lock.

The seconded one continued to percolate...forever! I finally checked it today and it was SG .990. Still blowing bubbles. I racked it for a second time into another carboy, reapplied the air lock, and it's still blowing bubbles. It's been 26 days! The SG says it's done. The wine disagrees. What's up with THAT?

Comments?

 

[BernardSmith]

All that bubbles suggest is that gas is being expelled through the airlock. It does not say anything about any new amounts of gas being produced only that what is in the carboy is being expelled and since half the weight of the sugars in the must are transformed into CO2 if the liquid cannot hold that gas - and it cannot - then that gas will try to find the easiest way out, so what you may be seeing is gas that was produced weeks ago is being forced out and the reason why it may be being forced out now is that fruit or yeast particles may be flocculating (collecting and dropping out of suspension) and their flocculation may be causing the gas to nucleate and nucleation allows gases to gather and collect with less energy - and their collection will enable them to escape suspension in the liquid... Bottom line, the only (for all intents and purposes) useful way to determine if fermentation is still going on is to measure any changes in gravity. No change? No fermentation..Watching bubbles is amusing but not very informative.
But all that said, I have a very different question? What was your reason for diluting your apple juice with water? You prefer the flavor of diluted juice?

 

[Old Philosopher]

All that bubbles suggest is that gas is being expelled through the airlock. It does not say anything about any new amounts of gas being produced only that what is in the carboy is being expelled and since half the weight of the sugars in the must are transformed into CO2 if the liquid cannot hold that gas - and it cannot - then that gas will try to find the easiest way out, so what you may be seeing is gas that was produced weeks ago is being forced out and the reason why it may be being forced out now is that fruit or yeast particles may be flocculating (collecting and dropping out of suspension) and their flocculation may be causing the gas to nucleate and nucleation allows gases to gather and collect with less energy - and their collection will enable them to escape suspension in the liquid... Bottom line, the only (for all intents and purposes) useful way to determine if fermentation is still going on is to measure any changes in gravity. No change? No fermentation..Watching bubbles is amusing but not very informative.
But all that said, I have a very different question? What was your reason for diluting your apple juice with water? You prefer the flavor of diluted juice?

The real puzzlement here was why two identical batches fermented at such different rates? As I said, I racked the slow batch a 2nd time, to remove the sediment and we'll see what happens over the next couple of days.

As for diluting the pressed juice, I'm processing about 700 lbs of apples.
I do three different products. Some I finish as hard cider, starting with 100% juice @ ~SG 1.052 and use Premier Cuvee yeast to give me an ABV around 6%. In another process, I use 100% juice and bump the SG up to around 1.090, giving me a full body @ ~12% ABV. My wife likes a lighter flavor, so I do the 3:1 ratio and bring that in around 15-16% ABV.

 

[Arne]

Think you may have a chance of a wild mlf going on. When they get done, compare the two wines and see if the one that took longer isn't smoother tasting. Just a guess, but have had it happen. At least I think that is what it was. Arne.

 

[BernardSmith]

Think you may have a chance of a wild mlf going on. When they get done, compare the two wines and see if the one that took longer isn't smoother tasting. Just a guess, but have had it happen. At least I think that is what it was. Arne.

But there is a chromatography test for MLF. Taste is also a test but is quite subjective especially if not performed "blind"

 

[salcoco]

as the major acid in apple is malic, I would assume that post mlf the wine will be very bland and flabby as it will be without any acid but lactic. may not be a very good apple wine.

 

[Arne]

But there is a chromatography test for MLF. Taste is also a test but is quite subjective especially if not performed "blind"

I know there is a test, but I do not have the equipment for it and it is a long way from here to a store that might have it. Anyway, I am just guessing and throwing an idea out there. And Bernard, thank you for throwing that in as he might have the chromatography test equipment. Arne.

 

[GreginND]

I've had plenty of apple wine batches undergo spontaneous MLF. Some even completed MLF before the primary ferment was done. Most likely the culprit.