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Changing pH of wash


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  • 7 months later...

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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  • 2 weeks later...

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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  • 3 weeks later...

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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  • 1 month later...

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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  • 3 weeks later...

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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You're right, yes, that would count as pasteurization.

But in terms of what heating our mash does -- certain strains of bacteria can survive temperatures up to 70-80 degrees. Certain strains of clostridium can even survive boiling, which creates a challenge for large scale food preservation - canned foods are heated by pressurized steam to 120+ degrees Celsius!

Since most of us are heating to only 63-67c, many strains of lactobacillus survive and will gradually take over the mash, working anaerobically on it, as the fermentation winds down and yeast autolyzes into nutrients.

This is, of course, ideal - lactobacillus is essential to the character of a developing whisky as it ages. They produce lactic acid itself, and many other compounds which are desirable flavor precursors. We just don't want them metabolizing citric acid.

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