Author Topic: What Happens to pH When Wort is Diluted?  (Read 937 times)

Offline johnnyb

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What Happens to pH When Wort is Diluted?
« on: July 18, 2015, 10:36:28 PM »
Time for another dumb question.

I am partway into brewing a gose and collected 6 gallons to sour with lacto bacteria.

Once the pH got down to 3.6 I was going to add about 1 gallon of water and then boil back down to about 5.25 gallons before pitching my finishing yeast. (I only had a 6 gallon carboy to sour the wort in so couldn't collect my normal pre-boil volume, which is why I was planning to dilute.)

But now I realized diluting the wort will raise the pH, and I don't believe boiling it back down will lower it back again, correct? Does anyone know for sure?


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Re: What Happens to pH When Wort is Diluted?
« Reply #1 on: July 18, 2015, 10:59:21 PM »
Time for another dumb question.

I am partway into brewing a gose and collected 6 gallons to sour with lacto bacteria.

Once the pH got down to 3.6 I was going to add about 1 gallon of water and then boil back down to about 5.25 gallons before pitching my finishing yeast. (I only had a 6 gallon carboy to sour the wort in so couldn't collect my normal pre-boil volume, which is why I was planning to dilute.)

But now I realized diluting the wort will raise the pH, and I don't believe boiling it back down will lower it back again, correct? Does anyone know for sure?

depends on water profile how much PH shifted- distilled, RO, tap??? regardless, only way to know where you're at is take PH reading again.
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Offline johnnyb

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Re: What Happens to pH When Wort is Diluted?
« Reply #2 on: July 18, 2015, 11:05:52 PM »
It's distilled that's adjusted just enough to get 50 ppm calcium and roughly balance the sulfate and chloride, and then 1.5 ml lactic acid to get the pH into the correct range for the mash.

I don't think it will really have any buffering capacity, but I don't really understand water chemistry. I know just enough to use Bru'n water which pretty much does it for you.





 

Offline kramerog

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Re: What Happens to pH When Wort is Diluted?
« Reply #3 on: July 18, 2015, 11:54:57 PM »
What will happen during the boil is somewhat unknown as lactic acid will also vaporize with the boiling water.  I suspect that the pH will go down due to the boil but it likely won't go back down to 3.6.

If you can get your hands on a gallon jug, I recommend splitting the beer between the jug and the ferementer and then pitch a large amount of yeast without doing the dilution and the boil.  You could heat the beer to pasteuriization temps if you want before pitching yeast.

Offline johnnyb

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Re: What Happens to pH When Wort is Diluted?
« Reply #4 on: July 19, 2015, 12:10:02 AM »
What will happen during the boil is somewhat unknown as lactic acid will also vaporize with the boiling water.  I suspect that the pH will go down due to the boil but it likely won't go back down to 3.6.

If you can get your hands on a gallon jug, I recommend splitting the beer between the jug and the ferementer and then pitch a large amount of yeast without doing the dilution and the boil.  You could heat the beer to pasteuriization temps if you want before pitching yeast.

I haven't boiled any hops in the wort yet. Today I just brought it up to 180 and held it for 15 minutes. If I kill off the lactic bacteria without boiling, and finish with WY1007, it will likely finish around 1.008 or so. I was hoping to get a few IBUs to balance the bit of residual sugars. Plus at the end of the boil I was going to add coriander for 5 minutes.


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Re: What Happens to pH When Wort is Diluted?
« Reply #5 on: July 19, 2015, 12:16:50 AM »
If your pH is 3.6 you have plenty of acidity to balance the residual sugar.

Offline johnnyb

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Re: What Happens to pH When Wort is Diluted?
« Reply #6 on: July 19, 2015, 12:26:30 AM »
If your pH is 3.6 you have plenty of acidity to balance the residual sugar.

Based on the experience of people using the lactic blend I used, I shouldn't have any trouble hitting 3.6 and it will go lower if I don't stop it.

But I have a problem -- I calculated the recipe planning to boil, plus I missed my SG by 3 points so my wort currently sits at 1.033. I was shooting for 1.036 then was going to add back some water and boil down to about 1.042 before I realized I would be diluting the pH by adding the water.

Maybe I'll see if the lactic will bring it down to like 3.1 like it has for other folks. Then I can dilute it a little bit and still do the boil to get a higher final gravity and get the hops and coriander in there.

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Re: What Happens to pH When Wort is Diluted?
« Reply #7 on: July 19, 2015, 12:49:12 AM »
I don't think it will really have any buffering capacity

It sounds like you're using distilled water, so no buffering capacity. The boil may have a small effect, but if you're only reducing it by ~20% you may not even see the difference.
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Offline johnnyb

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Re: What Happens to pH When Wort is Diluted?
« Reply #8 on: July 19, 2015, 12:57:10 AM »
I don't think it will really have any buffering capacity

It sounds like you're using distilled water, so no buffering capacity. The boil may have a small effect, but if you're only reducing it by ~20% you may not even see the difference.

When you say reducing it by 20% do you mean the dilution or the boil off?

It's the dilution that I'm worried about. I think diluting it will definitely reduce the pH, and then I think it will roughly maintain through the boil whatever the diluted pH happens to be. But then again I'm not really sure...


 

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Re: What Happens to pH When Wort is Diluted?
« Reply #9 on: July 19, 2015, 01:23:22 AM »
why not do a shorter boil? 30 minutes will get you your IBU and give an opportunity to add the coriander.
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Offline johnnyb

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Re: What Happens to pH When Wort is Diluted?
« Reply #10 on: July 19, 2015, 01:47:14 AM »
why not do a shorter boil? 30 minutes will get you your IBU and give an opportunity to add the coriander.

It's 60% pils malt -- do you think I'll have any DMS problems boiling for only 30 minutes?


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Re: What Happens to pH When Wort is Diluted?
« Reply #11 on: July 19, 2015, 01:48:50 AM »
When you say reducing it by 20% do you mean the dilution or the boil off?

I meant the boil off. It sounded like you're diluting with distilled water, so little to no pH change there. Boiling I would expect to reduce it, but pH is a log scale - a 20% reduction in volume, even if it's all water that boils off, drops the pH from 3.6 to ~3.5.
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Offline johnnyb

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Re: What Happens to pH When Wort is Diluted?
« Reply #12 on: July 19, 2015, 02:03:50 AM »
When you say reducing it by 20% do you mean the dilution or the boil off?

I meant the boil off. It sounded like you're diluting with distilled water, so little to no pH change there. Boiling I would expect to reduce it, but pH is a log scale - a 20% reduction in volume, even if it's all water that boils off, drops the pH from 3.6 to ~3.5.

Sweet! Sounds like I'm worrying about nothing!

I was afraid diluting it about 16% with distilled would have a big affect on the pH.

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Re: What Happens to pH When Wort is Diluted?
« Reply #13 on: July 19, 2015, 02:20:33 AM »
why not do a shorter boil? 30 minutes will get you your IBU and give an opportunity to add the coriander.

It's 60% pils malt -- do you think I'll have any DMS problems boiling for only 30 minutes?
Berliner wiesse is mostly pills and its is often not boiled at all. I don't know for sure that you wouldn't have a problem but absent other options it's worth a try. Sounds like you do have other options though
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Offline johnnyb

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Re: What Happens to pH When Wort is Diluted?
« Reply #14 on: July 19, 2015, 02:38:45 AM »
why not do a shorter boil? 30 minutes will get you your IBU and give an opportunity to add the coriander.

It's 60% pils malt -- do you think I'll have any DMS problems boiling for only 30 minutes?
Berliner wiesse is mostly pills and its is often not boiled at all. I don't know for sure that you wouldn't have a problem but absent other options it's worth a try. Sounds like you do have other options though

I'm not sure it's fully understood because I've been reading a ton lately about these beers and there is a ton of conflicting information, but the theory is if you only bring the temp up to pasteurization temps (like 170ish) then the SMM never converts to DMS. It only gets formed above something like 176. (Anyone reading this take it with a grain of salt because I'm relying on my memory and the temps might be off a little.)

Once you get the temp above the level of DMS formation then you need to boil to drive it off.

So the no boil guys are trying to bring the wort above pasteurization temps but keep it below the temp of DMS formation from SMM.