Low pH affect fermentation?

Help Support Wine Making Talk:

mhopkins

Supporting Members
WMT Supporter
Joined
May 13, 2017
Messages
116
Reaction score
32
Location
Colorado
I have a cranberry lime batch that is fermenting exceptionally slowly. I wondered about pH so I got a pH tester and began testing this morning.  
HISTORY - My first batch of cranberry lime done 6 months ago fermented slow ... starting SG was 1.086 and finished at Day 31 with a SG of 0.996. The finished pH sits at 3.2. Although in the lower range of target pH, this wine is delicious!
TODAY - The current batch initial SG was 1.102 and today at Day 45 is at SG 1.020 with a pH of 2.9. The SG continues to fall very slowly (7 days ago was 1.024). The must generates a very few observable bubbles. QUESTION - Does low pH slow fermentation (I cannot find a pH tolerance chart for yeasts)? Do you think it worth adding a bit of potassium bicarbonate to bring the pH up a little?
 

salcoco

Veteran Wine Maker
WMT Supporter
Joined
Jan 1, 2007
Messages
2,555
Reaction score
941
Location
Kansas
I would leave it as is. don't try to fix something that is not broke. Cranberry is notoriously slow to ferment because of some of the acids. the low ph doesn't help it would be better at 3.3 but the cranberry would still slowly ferment.
 

Rice_Guy

Senior Member
Joined
Jan 29, 2014
Messages
537
Reaction score
318
Location
midwest
I would not be surprised if the pH went up by 0.2 by simply degassing.
If it is still fermenting patience is a virtue.
 

mhopkins

Supporting Members
WMT Supporter
Joined
May 13, 2017
Messages
116
Reaction score
32
Location
Colorado
I would leave it as is. don't try to fix something that is not broke. Cranberry is notoriously slow to ferment because of some of the acids. the low ph doesn't help it would be better at 3.3 but the cranberry would still slowly ferment.
Thanks for the input!
 

jgmillr1

owner, winemaker
Joined
Jun 13, 2017
Messages
462
Reaction score
227
QUESTION - Does low pH slow fermentation (I cannot find a pH tolerance chart for yeasts)? Do you think it worth adding a bit of potassium bicarbonate to bring the pH up a little?
I've noticed that the yeast struggle when the pH is under 3.1. They will ferment but slowly over the span of a month or more.

As far as adjusting the acidity of the wine, you would want to measure the TA and target adjustments to get it where you want it to be. I've made cranberry wine from cranberries and added calcium carbonate to adjust the TA. It brought up the pH in the range of 3.2-3.3 where the yeast were happy and it fermented quickly.
 

Scooter68

Fruit "Wine" Maker
Joined
Aug 29, 2015
Messages
3,031
Reaction score
1,431
Wine musts are a complex combination so if the variables change the outcome may be different. And of course different yeast varieties have different tolerances to acidity and a host of other conditions. (Nutrients, temperature, sugar levels, etc) I've had blueberry wine ferment super rapid at a pH in the 3.10-3.2 range.
 
Group Builder
Top