Acidity in fresh juice

[rodfrey]

Hi! I've done a few kits here and there, following the instructions pretty religiously. This year though, I bought four pails of fresh juice from Mosti Mondiale. I bought an Amorosso, a Nebbiolo, a Barbera, and a Sauv Blanc.

The juice was almost-frozen (about -2C, not icy apparently because of the sugar). I warmed it to room temperature and added a gallon of wine skins to each of the reds. It comes per-inoculated with an unknown yeast (according to the retailer it's "carefully selected, perfect for this grape" but he didn't know what it was. I might write Mosti Mondiale to ask.)

My question is about pH. I bought the Apera PH60 tester, https://www.amazon.ca/gp/product/B01ENFOIQE/?th=1 and measured the acidity of each. I got the following:

Amorosso: 3.83 (23% brix)
Nebbiolo: 3.72 (23.5% brix)
Barbera: 3.78 (22.5% brix)
Sauv Blanc: 3.53 (22.5% brix)

From what I've read, this might be quite high since pH will rise during fermentation. For example Optimal Sugar and Acid Levels for Popular Wine Grape Varieties suggests a pH of 3.2-3.4 for most red wine musts (although these grapes aren't listed) and even lower for Sauv Blanc.

I asked the retailer and he said don't do anything, these juices are perfect. But should I add some tartaric acid and reduce the pH to the 3.3 range for the reds and 3.0 range for the white? Or just leave well enough alone?

Fermentation is *just* starting, a tiny bit of foam spots on the surface.

Thanks from an eager rookie!

 

[mainshipfred]

Honestly, it's to each their own. My preference is a more acidic wine but it's really about balance. To me the numbers posted on the Amazon link for red wines are a bit low to begin with. If you were to lower the pH I wouldn't recommend anything more than .2, maybe .3 for the Sauv Blanc.

 

[rodfrey]

Thanks Fred. (Not that it matters, but the acid levels were from Rick Haibach who does a youtube channel I've been watching, not Amazon.) It's good if the levels aren't at a dangerous level (because of protection etc), but still a matter of taste.

 

[mainshipfred]

Thanks Fred. (Not that it matters, but the acid levels were from Rick Haibach who does a youtube channel I've been watching, not Amazon.) It's good if the levels aren't at a dangerous level (because of protection etc), but still a matter of taste.

Oops, I saw the Amazon link for the pH meter. BTW my son just bought the same meter for growing pot. My other son is into saltwater aquariums so in one way or another we are all taking crash chemistry courses and pH is a common denominator.

 

[CDrew]

Honestly, if you are new at this, leave them alone. You'll have enough other things to think about. And these juice buckets may have been adjusted already, so there's that unknown. And next year you may decide to make wine from grapes where there will be more variability. For myself I consider 3.6 about right for red wine and 3.2-3.4 or so for white wine.

With that said, can you measure TA? If so, you can use that to think about your adjustments. For instance, if your pH 3.83 Amorosso had a TA below 6, I'd definitely consider adjusting it a bit and get the pH down a bit and raise the total acid level, but just by a little.

If you are into adjustments, I'd mess with the Barbera. It is supposed to be a high acid grape. I'd take that to roughly 3.6 and raise the brix to 24. I don't know where HWC got their numbers but 3.2-3.4 sounds low for most red wines. I usually get higher numbers than that and consider 3.6 about optimal. But otherwise, I like the Home Winemaking Channel. His explanations are thoughtful, clear and no hype.

Also remember to only use naturally derived Tartaric acid, not acid blend.

Good luck.

 

[cmason1957]

3.2-34 is much to low for reds (at least that's my opinion) and same with 3.0 for whites. If I adjust I shoot for 3.6 for reds and 3.2-3.4 for whites. Lower pH means it will probably taste better a bit sweeter. So my $0.02 is the same as the others, leave them alone. You can assume that the added yeast was EC-1118, it will ferment anything, doesn't add nor detract much from the ferment. Since this is your first ferment, I would have some oak cubes or oak sticks ready to add to your carboy, once fermentation is fully completed, for the reds. The white I'm not a fan of oak in.

 

[stickman]

The advice you are getting above is good, but you really need to confident the numbers measured are accurate. You mentioned something about the pails being near frozen when received, so be aware that tartrates may have dropped out, they'll be sitting on the bottom of the pail and won't be represented in your pH measurements until the juice is warmed up and completely mixed.

 

[rodfrey]

Thanks for all the advice! It's comforting to know that the pH isn't out of whack. I measured again today, juice was at about 18C and I got similar numbers, thanks for the pointer on tartrates dropping out at cold temps.

Sounds like my best course of action is to:
1) measure the T.A. - don't have the kit for that but I'll get it
2) don't mess with the Amorosso or Nebbiolo, but bring the Barbera down a bit.
3) relax

Thanks everyone!

 

[CDrew]

I would say the most important step is #3.

Yeast is going to be yeast and so you will have wine regardless. Juice pail wine is not something to age for decades so it will be fine.

 

[rodfrey]

Quick update - I'm certainly glad I took people's advice to sit tight, and I'm pretty sure that stickman was correct about the tartrates. After a couple days of pretty vigorous fermentation, pH has dropped to the 3.1-3.2 range (which I'm now worried is too low!) (Not really, I'm taking the advice to not worry to heart). The fermentation and associated heat must have stirred up the tartrates.

 

[CDrew]

Quick update - I'm certainly glad I took people's advice to sit tight, and I'm pretty sure that stickman was correct about the tartrates. After a couple days of pretty vigorous fermentation, pH has dropped to the 3.1-3.2 range (which I'm now worried is too low!) (Not really, I'm taking the advice to not worry to heart). The fermentation and associated heat must have stirred up the tartrates.

Glad things are going well. During fermentation though, all the CO2 being produced makes Carbonic acid when it dissolves in the wine, lowering the pH. Just a reminder that other factors are in play. Once it finishes, you can shake a sample vigorously, drive out the CO2 and then take your measurements.

 

[mainshipfred]

Not to dispute what seems to be accepted knowledge but I just Did a gravity test on a Viognier that read 1.015 with a finish hydrometer. Then put the sample in a beaker on a magnetic stirrer for 15 minutes or so. When I tested it again it was 1.014. Now this was only one test with a close to finish wine so it's far from an accurate study. It was surprising though how close it was. Perhaps if it was under more vigorous conditions the results might be different.

 

[sour_grapes]

Not to dispute what seems to be accepted knowledge but I just Did a gravity test on a Viognier that read 1.015 with a finish hydrometer. Then put the sample in a beaker on a magnetic stirrer for 15 minutes or so. When I tested it again it was 1.014. Now this was only one test with a close to finish wine so it's far from an accurate study. It was surprising though how close it was. Perhaps if it was under more vigorous conditions the results might be different.

Sorry, Fred, but I am confused: what accepted knowledge does your test conflict with?

 

[mainshipfred]

Sorry, Fred, but I am confused: what accepted knowledge does your test conflict with?

I thought most say you can't get an accurate hydrometer reading with the presence of CO2.

 

[rodfrey]

Hi Fred - I think the advice I've been given is the pH readings are a problem with a bunch of CO2 hanging around, rather than hydrometer readings. I use a pH meter for that.

 

[mainshipfred]

Hi Fred - I think the advice I've been given is the pH readings are a problem with a bunch of CO2 hanging around, rather than hydrometer readings. I use a pH meter for that.

You're right, I misread it, but I'm thinking folks say the same thing about gravity readings with regard to CO2.

 

[cmason1957]

You're right, I misread it, but I'm thinking folks say the same thing about gravity readings with regard to CO2.

Fred, folks do say the same thing about hydrometers and it's kinda true during fairly active fermentation. the CO2 rising, will adhere to your hydrometer and give you a slightly higher reading. I would think the CO2 doesn't care if it is a higher accuracy finish hydrometer or just a plain jane one. They are both going to read just a bit higher than it really should. The initial, quickest reading is closer to the correct one. Worst case example a straw in a rapidly degassing heavily carbonated soda.