LADistiller

Changing pH of wash

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I understand that most people use Calcium Carbonate to increase the pH, but what is used to do the opposite or decrease the pH?

Cheers

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Citric acid...

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Your local bulk chemical suppliers should be able to get you a 50 pound bag of USP grade citric for about 50 bucks, there is not much simpler than that.

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starting PH in our city water around 8.5. a tiny Citric addition brings us down to 6

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If I go lower in pH, it is because I want to create a little bit more taste. Lower pH enhances the formation of taste molecules (Esterification). So I do it on rum and whiskey, but not on vodka recipes. When I make (or help develop) taste rich products, like rum or whiskey, I use (or advice to use) backset. It is sour and will sour up mashing and fermentation, enhancing esterification. Since you now add backset, instead of water, to the next mash/ferment/distillation cycle, you also increase taste, you don't need (so much) yeast nutrients, and it helps you stabilize on taste output (repeatability).

In general, I aim for a much lower pH, especially while fermenting (where most taste is formed). It does not only help create more taste (and a more interesting whiskey or rum), it also helps against bacterial infections, when pH is below pH 4.8. Low pH is good against all bacterial infections ... safe lactic bacteria infection, unfortunately. I usually aim for a starting pH, while fermenting, of pH 4.8 and will see it go down to pH 3.8, depending on wash type (malts having more buffering capacity than grains having more buffering capacity than molasses).

If it goes below pH 3.5, I know that next time I have to add a bit of lime to start with, so it does not get more sour than pH 3.8. I don't like it lower than that because (again, depending on sugar source) ferments tend to stall below that.

Regards, Odin.

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American tartaric and univar carry bulk.  Probably a brewers supply would too.  Most winery supply houses carry citric and Phosphoric can vary in %.

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Get a bucket with a liquid tight lid.  Weevils like to get into the citric.  Some other bugs do too. What a pain.  Nice thing about citric vs phosphoric is citric is dry.

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It really depends on your specific circumstances I think, theres so many variables. So trying to identify a source of the issue is a good idea. For small mash adjustments with H20 that began around 7 with moderate carbonate than Phosphoric is best, citric is alright. If your water is low in calcium to start with than you can use calcium sulfate or calcium chloride (or a combination) which will reduce ph some as well as adding calcium. Nothing beats backset if you are using mostly corn, but most will agree its not super manageable on a micro scale. If your water is high in carbonate to start with and you're mashing corn than I reckon it would be worth while to figure out backset.

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baking soda or koh also work to increase alkalinity. 

Backset is probably the most realistic option for you - Idk your particular situation though.  Citric acid is my preferred choice for lowering pH.  The other options work but you never said why you want to lower pH and in what circumstance you need it lowered... Citric is easy to handle and store though.  two 5 gallon buckets works. 

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Rather than adjusting without first titrating, perhaps adding a pH buffer to avoid change is a good idea. 

Backset works if you're already collecting it. But it can be messy if you aren't. 

At what point are you needing to acidify?

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Backset really does make a significant difference, even at small volumes.  We use less than 5% of the total wash volume as backset (20 gallons in 530 total), and that has a material impact on buffering and the amount of citric we will need to use to drop pH.  Probably something on the order of 20-25% of the total citric we use in a non-backset batch.  And this is only because I'm somewhat anal about pH ranges during the mash - so I'll typically be using citric to step adjust pH anyhow - just use significantly less of it.

We also top off with chilled water prior to cooling (just as a way to reduce the cooling load/time) - and this is where you see the buffer impact.  Typically we would need to readjust pH after the final cold water addition.  With backset added, we never do.

We basically fill a small drum with boiling backset as soon as we finish off tails.  The heat helps to keep the backset somewhat sterile until the next run.  If your drum was clean and sanitized, you could probably hold the backset for a week or two, especially if you are dumping it into a cereal mash and re-boiling for an extended period of time (any new bacterial load would be killed).

Just don't put 20 gallons of boiling backset in a 55 gallon drum and seal it airtight during the middle of winter.

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Are you adjusting at the beginning of the mashing process, or before transferring to your fermentation tanks? Are you measuring your PH throughout the process (PH differences with temp), at the beginning, end, etc

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I've occasionally used phosphoric, which we always have on hand to adjust the pH of our Star San tub below 2.9. That way, the Star San lasts and works until you can't stand looking at it.

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If you are not pasteurizing your mash, like most don't, then citric is less than ideal. Certain strains of lactobacilli will metabolize it into diacetyl.

Instead, malic acid is ideal - it does not impact the performance of fermentation like some organic acids do, and is metabolized into the very ideal lactic acid by bacteria.

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On 4/13/2017 at 6:31 AM, MDH said:

If you are not pasteurizing your mash, like most don't, then citric is less than ideal. Certain strains of lactobacilli will metabolize it into diacetyl.

Instead, malic acid is ideal - it does not impact the performance of fermentation like some organic acids do, and is metabolized into the very ideal lactic acid by bacteria.

Not trying to start a rap-battle here, but wouldn't the actual process of mashing count as pasteurization?  flash pasteurizing is 15 seconds at 160 for juices I believe... obviously that doesn't change the fact that lacto can be practically epidemic in open ferments

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