Mash pH clarification

[premington]

haha sounds fun. in for a penny in for a pound...add the flaked adjuncts they could make a difference.

ph of your water is really not the issue. it is ph of the mash which includes the water, grist and brewing salts (and acid if using). even if your water ph changes some day to day I don't think that matters, most of the impact comes from the grist. Would be good to model it in Bru'n water or brewers friend first, then see how close the test results come to the predicted results.

Yes... I've done that. The entire recipe with water additions are in both Bru'n Water and Beersmith. Great tools that work well together! I'll definitely be comparing the results against the projected value in Bru'n Water.

I'll add the flaked rice and wheat also. Can't hurt and makes the test true to what the actual mash will be. I'll also treat 1 gallon of water with the proper salts and will adjust the pH with each test.

Then I'll see what I get! I agree... FUN!

 

[eric19312]

yes and be sure to post results back here along with what happens during the actual brew.

 

[rayg]

I would urge anyone interested in the topics of mash pH and mash temperatures
to consult volume 1 of "Malting and Brewing Science" by Briggs, Hough, Stevens
and Young.

Ray

 

[Hwk-I-St8]

That works if you want to make adjustments.....to the next batch. By 10 minutes a lot of the conversion has already happened so if your pH is off it's too late to correct for this batch. Unless you repeat the same grain bill you won't know for sure what the pH will turn out like.

I don't think chasing ph during the mash is a recipe for success. Use the tools out there to estimate/adjust ph for your recipe, measure the result and adjust the model for future batches.

I use Bru'n water and have been extremely close each time. I've had no reason to change for subsequent brews.

 

[premington]

Well, I brewed the American Ale after doing a series of test mashes at various pH levels. The test mashes helped me decide to set the water pH at 5.8. About 20 minutes after dough in, I measured the mash pH at 5.35. My target was 5.4, so I was very pleased with this result.

This thread, the advice of AJ and others here, and the test mashes were hugely helpful and educational. Thanks to everyone here for that. During future brews, I plan to set the water pH to below 6.0.

 

[ajdelange]

I would urge anyone interested in the topics of mash pH and mash temperatures
to consult volume 1 of "Malting and Brewing Science" by Briggs, Hough, Stevens
and Young.

While BHS&Y should be in any serious brewer's library one has to recognize that it was written in 1981 (second edition) and the science, or, perhaps more precisely, the way brewers think about the science, has been updated since then. That alone should encourage readers to seek a more modern source such as Palmer's Water which, while it doesn't carry the prestige of having been published by Chapman and Hall does contain the updated science. That isn't to say that one shouldn't read the BHS&Y material too. Just take it with a grain of salt.

Section 9.1 in BHS&Y is quite misleading. It lists the equations

Ca(HCO3)2 <---> Ca++ 2HCO3-

and then

HCO3- + H2O <---> H2CO3 + OH- <---> H2O + CO2 + OH-

going on to state that this implies that solutions with bicarbonate hardness become more alkaline upon heating. But we all know this to be untrue. Heated liquors with temporary hardness become less alkaline. The authors here have ignored the fact that simultaneous with the reaction they list the reaction

Ca++ + HCO3- <---> CaCO3 + H+

in which calcium carbonate is precipitated, is also taking place. That hydrogen ion can be thought of as neutralizing the OH- from the reaction they list or it can be thought of as the source of the hydrogen ion that converts bicarbonate to carbonic acid. In any case the overall reaction when liquor with temporary hardness is heated is

Ca(HCO3)2 <---> CaCO3 + CO2 + H2O

Because the liquor which has been heated contains less carbo than it did before heating it is less alkaline (though its pH may have risen during the heating process).

The material in Palmer's book is somewhat expanded upon in "Predicting and Controlling Mash pH Using Simple Models for Mash Component Acid/Base Characteristics" MBAA TQ vol. 52, no. 1 &#8226; 2015 Certainly the time between publication of the book and the paper allowed me to clarify my thinking relative to when this stuff was first fed to John and he didn't use everything I gave him so read his book and the paper for fullest understanding.

 

[rayg]

Well, I brewed the American Ale after doing a series of test mashes at various pH levels. The test mashes helped me decide to set the water pH at 5.8. About 20 minutes after dough in, I measured the mash pH at 5.35. My target was 5.4, so I was very pleased with this result.

This thread, the advice of AJ and others here, and the test mashes were hugely helpful and educational. Thanks to everyone here for that. During future brews, I plan to set the water pH to below 6.0.

But *why* did you do that? Any effect on flavor, quality, extract or whatever?

Ray

 

[Silver_Is_Money]

premington has adopted a two step approach to what most of us consolidate into one step.

1) Neutralize (or adjust to suit) the alkalinity of the strike water
2) Neutralize the acid or caustic nature of the grist with respect to a target/baseline of pH 5.4

This two step approach logically offers a bit more potential for precision and consistency in accomplishing the end goal of mashing at pH 5.4, albeit at the cost of a bit more work.

 

[premington]

premington has adopted a two step approach to what most of us consolidate into one step.

1) Neutralize (or adjust to suit) the alkalinity of the strike water
2) Neutralize the acid or caustic nature of the grist with respect to a target/baseline of pH 5.4

This two step approach logically offers a bit more potential for precision and consistency in accomplishing the end goal of mashing at pH 5.4, albeit at the cost of a bit more work.

Correct... Thanks for clarifying this.

I used the lactic acid to reduce the bicarbonate in the water so when it mixes with the grist at dough-in, the acid in the grain can do what it was intended to do, work towards converting starches to sugar rather than some of it binding to bicarbonate in the water. The addition of acid is to lower the water alkalinity to 0.

After all of the discussion in this thread, I think I understand this properly. If I'm still missing something, I'm happy to be corrected.

The ale, BTW, looks and tastes exactly as I had hoped. Wish ya'll could come over in a month or so and help me drink it.

 

[ajdelange]

You may still be a little unclear on what alkalinity is. It is, for water, the amount of acid that must be added to a liter of the water to reduce its pH from a reference pH to a target pH. Thus when you speak of reducing alkalinity to 0 you must specify the pH values involved. When mashing, the target pH is, of course, the desired mash pH. Yet you refer in an earlier post to setting water pH to 5.8. This would not result in 0 alkalinity at mash pH as additional acid would be required to lower the water's pH to the target 5.4.

 

[mongoose33]

You may still be a little unclear on what alkalinity is. It is, for water, the amount of acid that must be added to a liter of the water to reduce its pH from a reference pH to a target pH. Thus when you speak of reducing alkalinity to 0 you must specify the pH values involved. When mashing, the target pH is, of course, the desired mash pH. Yet you refer in an earlier post to setting water pH to 5.8. This would not result in 0 alkalinity at mash pH as additional acid would be required to lower the water's pH to the target 5.4.

But isn't that what the acidity of the grist is doing, i.e., lowering the pH?

 

[ajdelange]

If you have acid malts, yes, but I didn't think that was the case here. 'Acid malt' in this context means a malt with a DI mash pH of less than the target mash pH. If you have enough acid malt(s) in a grist to more than offset the alkalinity of the base malts then you would indeed not want to acidify the water to mash pH but to whatever pH is necessary such that its remaining alkalinity with respect to mash pH is numerically equal to the negative alkalinity of the malts as adjusted by the apparent acidity caused by the phytin reaction. It is unusual that this happens but sometimes, in beers with a lot of high kilned malt, it does.

 

[premington]

You may still be a little unclear on what alkalinity is. It is, for water, the amount of acid that must be added to a liter of the water to reduce its pH from a reference pH to a target pH. Thus when you speak of reducing alkalinity to 0 you must specify the pH values involved. When mashing, the target pH is, of course, the desired mash pH. Yet you refer in an earlier post to setting water pH to 5.8. This would not result in 0 alkalinity at mash pH as additional acid would be required to lower the water's pH to the target 5.4.

Well, I guess I was going by a previous discussion where I reported that once my test mashes hit about 5.8, any further titration resulted in no further reduction in mash pH. I thought you mentioned that's because the alkalinity had reached 0, and I had hit the bottom of the titration curve. Perhaps I misunderstood. As a result, I used 5.8 as a target for my mash water. This resulted in a mash pH of 5.35, which I was very pleased with.

I thought the idea was to reduce the bicarbonate level of my water before adding it at mash. So, mine was tested at 79. By adding lactic acid, I effectively lower this prior to adding it at dough-in. Doesn't this free-up the acid in the grain to focus on conversion rather than get bound up on the bicarbonate in the water?

It's a complicated subject I've learned a lot of people struggle wrapping their head around. I guess I'm still learning.

 

[ajdelange]

Well, I guess I was going by a previous discussion where I reported that once my test mashes hit about 5.8, any further titration resulted in no further reduction in mash pH.

That shouldn't be. Adding additional acid should result in continuing reduction of mash pH. Perhaps you did not stir thoroughly or wait long enough for the meter to stabilize.

I thought you mentioned that's because the alkalinity had reached 0, and I had hit the bottom of the titration curve. Perhaps I misunderstood.

When you reach mash pH the alkalinity is 0 WRT mash pH and you should not want to go any lower so no more acid is needed. When you reach pH 5.8, by contrast, you still have alkalinity WRT mash pH to contend with (unless the water contains no bicarbonate as, for example, RO water).

As a result, I used 5.8 as a target for my mash water. This resulted in a mash pH of 5.35, which I was very pleased with.

Can't explain that as mash pH should have continued to drop as you added more acid to the test mash and indeed if you reach 5.35 it must have done so.

I thought the idea was to reduce the bicarbonate level of my water before adding it at mash.

It is. But it does not go down to 0 alkalinity unless you get it to mash pH.

So, mine was tested at 79. By adding lactic acid, I effectively lower this prior to adding it at dough-in.

Doesn't this free-up the acid in the grain to focus on conversion rather than get bound up on the bicarbonate in the water?

Yes it does if you get the pH of the water to mash pH but there typically isn't any acid from the grain - most beers require extra acid be added to neutralize their (the grains) alkalinity.

It's a complicated subject I've learned a lot of people struggle wrapping their head around. I guess I'm still learning.

I know it is terribly confusing to newcomers to the subject. Don't despair!