Acid question

[M38A1]

There are no stupid questions, I used to answer the tech center phone and judge what type of answer to give based on the skill level/ if trade secrets were involved, ,, which a question reflected.

At this point you have a fresh vigorous fermentation. It is producing CO2 which will drop the pH and increase the TA. This turns into carbonic acid AKA soda type carbonation. in your mind compare fresh soda versus flat. ,,,, Is this the difference you taste in your new wine.
Sugar is magic. It hides a lot of faults.

For the learning curve if you could run numbers as is, ,,, and then heat 100 ml in a microwave for 60 seconds, carefully stir out the CO2, cool, and rerun, how much difference is there?

ok, I ran an SG today and it was 1.082 which confirms an active fermentation as my starting point was 1.103. I took 100ml of must, nuked it 60 seconds, (boy did it want to bubble the last 3 seconds!), removed it and stirred with a fork. Let that cool about an hour and ran pH and it was 2.6 or more acid than when I started if I understand correctly. I'm guessing the heating kills the yeast so it can't produce CO2 in addition to heating the solution so CO2 comes out easier under heat? That also eliminates any bubbles which might affect my pH instrument?

I think the reason I could have more acid is I removed the grapes/skins/seeds as much as I could and lightly pressed them to recover liquids. I also think the majority of the tart acid comes from the skins of these grapes. Now that 99% of the grapes/skins have been removed I'll be curious to see what that pH does in the next few days doing this same testing routine.

Can I add k-bicarb during an active fermentation? On the tail end? Or again, just let this ride?

I'll say it's a beautiful color at this point. That's a plus, right?

 

[cmason1957]

Don't trust the ph during a fermentation. I believe the CO2 in your sample acts like acid.

 

[M38A1]

So my open question is, can I reduce the acid during or after fermentation is complete?

 

[cmason1957]

I have always done it pre- or post- fermentation, never during.

 

[M38A1]

I have always done it pre- or post- fermentation, never during.

WOW. Thank you. So there's hope for this still!

 

[M38A1]

Followup question.... Does the addition of K-bicarb necessitate the use of cold crashing the carboy? My fridge/freezer isn't that big....

 

[Rice_Guy]

I agree with @cmason1957, if the fermentation is going well, don’t risk it.
Note; From the yeast literature, if you are at 2.6 you should have an extremely weak fermentation/ no fermentation/ one that gets stuck. I would wonder about the calibration on your pH meter.

An observation which I haven’t read anyplace or done enough to trust, ,, over the last year, when I checked the starting must versus the finished wine, it seemed that I gained 0.2 pH units. Related to this when checking pH and TA on finished wines they seem to be higher than they should for “good quality” reds and whites. It will be interesting to see if you get this too.

My preference is doing pH adjustment with calcium carbonate. The big negative is that it will settle since the reaction is slow (it’s actually ground limestone). Some rhurbarb recipes pull a portion of the juice out and react it, and then add that fraction back. Potassium bicarbonate reacts instantly, however adds potassium which is the bitter flavor note in light salt, ,, would rather not add K. If I do potassium bicarbonate I do small changes as less than 0.2 pH units.

back sweetening will balance the titratable acidity. , ,, if you don’t run TA a gauge is how drinkable was it? Real high TA is hard to drink Even with sugar.

Cold crashing, I mainly run fruit wines so I don’t worry about tartrates. Also, your friend has mustang grapes, Good question.

 

[M38A1]

Well this batch is still just rocking along. SG is now 1.030.

 

[M38A1]

Another question.... I'm at SG 1.01 today. There's roughly 4 gallons in a 7gal open top primary fermenter bucket where I keep a towel over it. I need to run out of town for a few days and I'm wondering if I should rack this off to a glass carboy with a bubbler and let it finish there. I'm thinking the fermentation is slowing down considerably exposing the top of the grape must to a lot of oxygen now. In a sealed carboy with a bubbler on top it can still ferment and off-gas while protecting the contents.

Thoughts?

 

[cmason1957]

Another question.... I'm at SG 1.01 today. There's roughly 4 gallons in a 7gal open top primary fermenter bucket where I keep a towel over it. I need to run out of town for a few days and I'm wondering if I should rack this off to a glass carboy with a bubbler and let it finish there. I'm thinking the fermentation is slowing down considerably exposing the top of the grape must to a lot of oxygen now. In a sealed carboy with a bubbler on top it can still ferment and off-gas while protecting the contents.

Thoughts?

Yes, you want to rack that. It might be okay in your bucket for a few days, but then again, it might not. In a well topped up carboy, it will be okay. I always try to get some (okay, I try to get most) of the stuff on the bottom of the bucket, those yeast cells are still working.

 

[M38A1]

Yes, you want to rack that. It might be okay in your bucket for a few days, but then again, it might not. In a well topped up carboy, it will be okay. I always try to get some (okay, I try to get most) of the stuff on the bottom of the bucket, those yeast cells are still working.

Thank you. I'll rack this tonight/tomorrow morning down to everything in the bottom, stick a bubbler on it with some vodka and not worry for a few days.