Help with calcium carbonate to increase pH

[Guest Bobcat Hill]

I've got a corn mash sitting at almost 1 day old with a 4.5 pH and would like to boost it to 5.5. The only instruction I can readily find on how to use calcium carbonate to increase pH is "add in small amounts." Any suggestions? I was thinking of diluting a tablespoon into a half liter of water and then mixing that with a bucket full of mash before adding it into the tank.

[Denver Distiller]

What do you mean by 1 day old? That it's been fermenting for 1 day?

[Guest Bobcat Hill]

Yes, it's been fermenting for one day now ...

[Denver Distiller]

IMHO, that's a pretty good pH to be at for a corn fermentation after a day. Why do you want to be all the way up to 5.5?

If you want that higher pH, you want to add salts in the mash water so that it has a chance to buffer the incoming acid (the liquified corn and malt). In other words, you want to arrest the acidification of water by that incoming corn.

You need to know the buffering capacity of the water in order to know do the molar calculations to know how much calcium carbonate you need to add. Or you can just go trial and error.... but IMHO, you want to add it to the water before you add the corn, so your buffering power holds that pH where you want it.

[Rickdiculous]

What is the volume of the fermentation? It's hard to give advice without knowing that.

[Rich Morgan]

Personally I would leave the pH of 4.5 for a couple of reasons;

1. The more a wash or ferment is above pH5, the greater the chance of bacterial/microbial infection. If your going to run a high pH of 5.5 you need to be sure your santisation is spot on.
   
2. Most Saccharomyces cerevisiae yeast perform better below pH5, not so much a factor in corn based wash's but very true for sucrose substrates
   

[Denver Distiller]

An addition, or rather a clarification, regarding yeast performance---- having the pH well below 5 is one key to making sure you get full attenuation of your mash by that yeast. There's a reason that most of us bourbon producers use the sour mash process.

[Guest Bobcat Hill]

Thanks to all for the feedback. The volume is 400 gallons divided between two tanks. The wish to hit 5.5 was simply because I was told 5.5 pH is an ideal range for corn mash. However, considering the comments posted here about a 4.5 pH's further advantages against bacterial activity and more attenuation is enough for me to keep it as is. Thanks again.

[JohninWV]

Bobcat Hill, our mash is about 5.2-5.5 (5.44 today, to be exact) before we pitch yeast. We get to about 3.9 to 4.1 when fermentation is complete. One of the things we've started to do is to check PH every day at 9 AM. We usually set and pitch about 1PM, so that means we check at 20 hrs, 44 hrs, 68 hrs, and 92 hrs. Once I have more data, I can send those charts to you. Maybe it's useful, maybe not.

From what we are learning, it appears variations in PH can be a very good sign of issues in your process early on. Again, I don't have enough data on our "in-between" points yet. I just know where we start and where we finish.