pH Drop after Alcoholic Fermentation?

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Kurtoxic

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I purchased a 6 gallon Chilean cab/merlot blend juice bucket (del toro) from M&M this spring. This year I seem to have had a large shift in pH and TA after alcoholic fermentation. PH meter was calibrated before each use and has been very reliable for me in the past. Also I am using fresh NaOH for each TA test. Has anyone else experienced this before? Did I unlock some hidden acidity with this one?

Pre Fermentation
Initial: pH=3.76; TA=2.1 g/L
Adjust: pH=3.4; TA=3.1 g/L; addition of 24g tartaric

Post Fermentation (w/ D254)
pH=3.12; TA=7 g/L
 

GreginND

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There are a number of things that can cause a pH drop after fermentation. I'll just mention a few . . .

1. Sample not degassed - CO2 will form carbonic acid in solution artificially increasing acid.
2. Pre-fermentation measurement invalid - bad measurement or acid addition not fully mixed/dissolved.
3. Change in buffering components after fermentation. e.g. - drop in potassium and other organic buffers allowing the acid strength to increase.
 

Scooter68

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As GreginND said an increase in acidity is not unusal. Best to monitor it and correct if the wine is overly acidic. I've seen commercial grape wines advertised with a pH of 3.18 so your reading is not way out of bounds.

Also when you post a question on here it helps to give dates/times so that we know how long a condition has existed of when it developed.

(You provided a good amount of info just a little bit more and it will make it easier for others to help you.)
 
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