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Doing the pH panic..


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Our rum recipe is roughly

  • 75% water
  • 25% backset
  • 70% TSAI molasses to 1050 or 12.5 brix
  • Nutrients additions spread out over the first three days (we following a mead-ish protocol)
  • Yeast @ approx .5g/liter

Temp controlled ferment at mid 80s F. This goes dry in 5ish days and we hold two other days for no reason other than production scheduling.  Now, the only issue we have is the seemingly random drop in pH. Our last run started at 4.0 and after three days was 3.1. Ouch.  We added 10 lbs of calcium bicarbonate which raised the pH to 3.9 to finish the ferment. Oddly enough the density didnt change the last two days of the ferment which means either (1) the yeast died due to ph or (2) their was no sugar remaining to ferment.  Any thoughts on this falling pH? Does this seems normal? Should we bother to adjust? I've heard some folks rapidly agitate to drive off disolved CO2 which affects pH. We've done this before. Ever seen a 600 gallon can of Coke shaken??   Just looking for some ideas for improving this process.


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Calcium hydroxide is more reactive and will raise pH more effectively. Buffer with calcium carbonate in the start of fermentation and dose again 1/2 way through fermentation. My pH doesn't crash anymore like that. Calcium hydroxide is very reactive so use it sparingly.

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The randomness might be changes in the incoming water.

The water companies add CaCO3 & CaOH to boost pH (reduce corrosivity).

The surface water water from The White River & Fall Creek change seasonally and adjusting the pH will require more/less additions.

This will effect the buffering capacity of the water and you could monitor this by measuring total alkalinity.



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On 5/3/2018 at 3:57 PM, Beach Time said:

The surface water water from The White River & Fall Creek

Hold on... your username is "Beach Time" and you know about Fall Creek & White Water pumping stations?? 

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Take with a grain of salt.

Backset might have lactic bacteria with it. They might be dropping the Ph. Try a batch with no backset and see if it has the same drop? Just do a complete clean out of the fermentor and I would say keep it away from others encase they might have something floating around in the air. 

A test I used to do is I would pull a small sample and cap it before I added yeast. Leave it alone and see if any bacteria growth takes over. If so that means two things could be going on. 

1. Bacteria is in my what I thought was sterile batch.

2. Bacteria managed to get into the batch from the air.


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  • 1 year later...

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