Hi, for a while I have added to my mash (35L) a good dash of orange juice for some acidity. Never measured it. Now I have made two batches exactly the same as before, but have used citric acid to bring ph to 5. I measure it with test paper.
Unfortunately fermentation stops at gravity of 1.02, not the usual 0.98. When I measure ph is 3 . No surprise fermentation stopped.
Could it be that the Co2 that is produced in the fermentation causes this much change in the ph?
Acidity
Moderator: Site Moderator
Re: Acidity
yeast will continue to ferment all the way down to 2.0. You probably made a beginners mistake and started At too high a gravity and alcohol killed the yeast. no higher than 1.080. oj is gonna make your spirits taste like metal,
Re: Acidity
What he said 
I've found that in my sugar washes the pH lowers something like a full point during fermentation. Its possible you measured you pH too quickly and got to oalkaline a reading, and the wash stabilized out at pH 4.
I also almost always use baker's yeast for fermentation of sugar and molasses since it is incredibly cheap, and I've been able to reliably get it to ferment out to 14% using stepped addition. If I am doing higher gravity I let it go for a couple of days then pitch in one packet of EC-1118 (started properly with some sugar and a tiny bit of DAP) and let it sit another 5 days. I've only had one stuck ferment, and that cleared up when I added a bit of Epsom salt (must have missed adding it on that batch).
I've found that in my sugar washes the pH lowers something like a full point during fermentation. Its possible you measured you pH too quickly and got to oalkaline a reading, and the wash stabilized out at pH 4.
I also almost always use baker's yeast for fermentation of sugar and molasses since it is incredibly cheap, and I've been able to reliably get it to ferment out to 14% using stepped addition. If I am doing higher gravity I let it go for a couple of days then pitch in one packet of EC-1118 (started properly with some sugar and a tiny bit of DAP) and let it sit another 5 days. I've only had one stuck ferment, and that cleared up when I added a bit of Epsom salt (must have missed adding it on that batch).