Author Topic: Adjusting pH during the mash.  (Read 14103 times)

Offline BigUnclePhil

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Adjusting pH during the mash.
« on: November 28, 2015, 11:40:24 AM »
Hello all.

I'm planning my 3rd all-grain batch, and have recently been doing some research into brewing water and mash pH.  I understand the basics, and it looks like my water profile (using the bru'n water spreadsheet) should get my mash pH to about 5.6 after dough-in.  Come brew day, if I don't hit 5.6 for some reason, are there any good resources for adjustments in the mash?  I'm finding a lot of information about adding lactic acid to lower the pH, and either calcium carbonate or sodium bicarbonate to raise it.  The problem is, I'm not finding any guidelines for how much to add.  One discussion I came across mentioned adding 1 single teaspoon of baking soda which raised the pH by one whole point and the brewer had to add in acid malt to dial back the pH.  This thread didn't list any other details though, such as how large the batch was, what style and grains, etc. 

So my main question is this--are there any tables or calculators that will help you determine the approximate amount of each additive to achieve the target pH? 

Thanks!

Offline brewinhard

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Re: Adjusting pH during the mash.
« Reply #1 on: November 28, 2015, 12:47:30 PM »
Do you have an accurate way of measuring your mash pH?  If not, then I would not bother making any adjustments as you simply won't know your starting pH to begin with.

Typically, I use 88% lactic acid to reduce mash pH and baking soda to increase mash pH.  After determining my salt additions for my mash and sparge water via Brunwater, I then go back to the water adjustment page and start adding in different amounts of lactic acid in the spreadsheet until the pH drops by .1 on the mash acidification page.  This then gives me a basic idea how much lactic acid will drop my mash pH by at least .1 which for me is a good start.

Then, I do the same thing but with baking soda (added to just the mash) on the spreadsheet until the mash pH increases by .1.  This then too gives me a basic starting point for how much to add to increase my mash pH by at least .1 if I need to or not. 

Hope this helps.  I can almost guarantee there will be others who chime in with a more refined way of estimating this, but I can only report on what I do and what works for me.  If my mash pH comes close enough to my target mash pH (i.e. was targeting a 5.4, but only hit a 5.36), then I usually just let it ride with no adjustments. 

Offline JT

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Re: Adjusting pH during the mash.
« Reply #2 on: November 28, 2015, 01:15:21 PM »
If you're close to target and within the acceptable range, I wouldn't bother trying to adjust.  It can be difficult and acid will be more effective than usual when the water is hot.  I've found raising the mash pH with salts to be more difficult than lowering.  Also, unless  you have a recirculating mash (and sometimes even if you do), you really cannot trust pH readings after adding additions.  It simply doesn't get mixed in enough. 
Best to take good notes and adjust future brews. 

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Offline hopfenundmalz

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Re: Adjusting pH during the mash.
« Reply #3 on: November 28, 2015, 02:08:27 PM »
Hint, calcium carbonate is not a good tool to raise the pH. The reaction is very slow, and the mash will be done before it all dissolves. Baking soda and pickling lime will dissolve quickly and raise the pH. The amount to go up or down depends on the buffering that goes on in the mash.
« Last Edit: November 28, 2015, 05:48:06 PM by hopfenundmalz »
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Re: Adjusting pH during the mash.
« Reply #4 on: November 28, 2015, 05:36:26 PM »
[quote author=hopfenundmalz link=topic=2512


THIS^^^^^
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Offline Wort-H.O.G.

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Re: Adjusting pH during the mash.
« Reply #5 on: November 29, 2015, 09:56:41 AM »
since you are using bru'nwater, that's going to guide you the best. once you have everything plugged in for your grist, source water profile, water volumes, and salt additions, you get a projected PH. If your projected PH is lower, you can then add baking soda additions to see what it takes to raise your PH to your desired target. same goes for lactic acid additions to lower PH to your desired target. it can be tricky at first, but if you have accurate entries for your source water - RO, distilled, or from your tap then the software really does a great job of predicting mash PH.  keep notes each time and you will dial it in and it will become repeatable.

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Offline mainebrewer

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Re: Adjusting pH during the mash.
« Reply #6 on: November 29, 2015, 12:12:23 PM »
I have a question related to the original post.
Assume, using your favorite water adjustment software, the pH is predicted to be 5.5 but the actual pH is 5.3.
Since the sample is pulled 15 min or so after mash in, the sample takes a few more minutes to cool to room temp, and then a couple more minutes for the actual measurement of the pH.

So, at this point, 20 or so minutes have passed.

Don't know how quickly the mash will respond to a addition of baking soda to raise the pH by .2 but let's assume that it took 5-10 minutes to get the baking soda measured, added to the mash and for the mash pH to increase. So now, we are around 30 minutes into a 60 min mash.

My question is will raising the pH at this point in the mash make any difference?
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Offline klickitat jim

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Re: Adjusting pH during the mash.
« Reply #7 on: November 29, 2015, 01:18:29 PM »
If you're like me, and I know I am, I measure pH at all stages when its a new recipe or if I make a grainbill change. I dont chase the ph though, im just verifying that the calculations were acurate and making notes for any necessary adjustments in the future. On a rebrew of tried and true recipes, I dont measure ph except on the last final gravity reading. I measure ph of final beer because I have a curiosity about the factors that create it and how it impacts flavor.

Offline PORTERHAUS

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Re: Adjusting pH during the mash.
« Reply #8 on: November 29, 2015, 01:27:22 PM »
I have a question related to the original post.
Assume, using your favorite water adjustment software, the pH is predicted to be 5.5 but the actual pH is 5.3.
Since the sample is pulled 15 min or so after mash in, the sample takes a few more minutes to cool to room temp, and then a couple more minutes for the actual measurement of the pH.

So, at this point, 20 or so minutes have passed.

Don't know how quickly the mash will respond to a addition of baking soda to raise the pH by .2 but let's assume that it took 5-10 minutes to get the baking soda measured, added to the mash and for the mash pH to increase. So now, we are around 30 minutes into a 60 min mash.

My question is will raising the pH at this point in the mash make any difference?

That's a good question. Lets start with 5.3 vs the predicted 5.5 ph. Having 5.3 would be just fine, it's in perfect range. But if you want an example say the actual ph was 5.1 and you wanted to raise it, in my experience adding Baking soda works rather quickly. As far as waiting for samples to cool, I use as small a sample as posible so that it cools quickly. I need maybe a tbl spoon in a small shot glass for a reading (with my meter anyway) that is all. I set it in the freezer for a min and check it to bring it down to room temp. It takes no time at all. So yeah while that process can take an extra minute or two I am usually no more than 15 mins into the mash at that time if once I mash in, check temp and ph and make adjustments if needed.

Is it worth any adjustment after 30 minutes, or make any difference...yes. Coversion is well underway by that point, but you still have half of the mash to work with. If you batch sparge, getting the mash ph in the right range will help buffer the sarge water you add if you do not acidify that seperately. That will help keep you from raising the ph too much in the sparge and extracting tannins. Getting the right mash ph will then help keep the boil ph fall in the optimal range as well. So yeah, adjustment is still worth it and has benefits.

I'll also note I know you were just using an example, but using a good water program like Bru'n Water or EZ water you should be well within the estimated ph, especially if working with RO or distilled water or know your tap water profile well. And if you do need adjustment, you can look to the water program to know how much to add.

Offline brewinhard

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Re: Adjusting pH during the mash.
« Reply #9 on: November 29, 2015, 06:32:51 PM »
Just out of curiosity- how many minutes into the mash is everyone taking their first sample?  5 min, 10 min?

I have been taking one 5 minutes after I reach my target mash temp.  I am assuming this is enough time for a proper pH to stabilize.  Any thoughts?

Offline mainebrewer

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Re: Adjusting pH during the mash.
« Reply #10 on: November 30, 2015, 01:41:43 AM »
I've been using Brunwater for a couple of years now and, if I get all my measurements done correctly, it is very accurate in it's ability to predict the mash pH.
I understand that getting the mash pH correct, even late in the mash, has positive downstream impact.
I was just wondering how much difference adjusting the mash pH at the 30 min mark or even the 15 min mark in the mash would have on the final percentage of conversion.

I have always pulled my sample 15 min after mashing in. Don't remember from where I got that info.
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Offline PORTERHAUS

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Re: Adjusting pH during the mash.
« Reply #11 on: November 30, 2015, 01:20:17 PM »
Sorry, I figured you were asking about the overall effects. So what effect adjusting halfway through the mash has on conversion...don't know.

As far as when I pull a sample...once I am mixed in well and I'm happy with temperature I pull a sample. That might be 5 mins in, might be more. It seems that is enough time for any reactions to take place. I have checked ph at or towards the end of the mash out of couriosity and have had very close readings to that of what I pulled at the begining so I guess for the most part a few minutes into the mash is just fine.
 

Offline Wort-H.O.G.

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Re: Adjusting pH during the mash.
« Reply #12 on: November 30, 2015, 02:16:41 PM »
Sorry, I figured you were asking about the overall effects. So what effect adjusting halfway through the mash has on conversion...don't know.

As far as when I pull a sample...once I am mixed in well and I'm happy with temperature I pull a sample. That might be 5 mins in, might be more. It seems that is enough time for any reactions to take place. I have checked ph at or towards the end of the mash out of couriosity and have had very close readings to that of what I pulled at the begining so I guess for the most part a few minutes into the mash is just fine.

same her. my reading occurs around 8-10 minutes from adding water and mixing.  if i get reading at 5.32, the sample measured at the end is within .02 of that first reading. 
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Offline BrodyR

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Re: Adjusting pH during the mash.
« Reply #13 on: November 30, 2015, 07:11:59 PM »
It will be a bit more work but I've heard using the old acid rest temps (95f or so) to dough in allows for no rush pH adjustments. At this temp there is not really much conversion going on so you can let the mash rest a bit, take a reading, and adjust before moving up to sach temps.


Offline blatz

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Re: Adjusting pH during the mash.
« Reply #14 on: November 30, 2015, 09:51:08 PM »
It will be a bit more work but I've heard using the old acid rest temps (95f or so) to dough in allows for no rush pH adjustments. At this temp there is not really much conversion going on so you can let the mash rest a bit, take a reading, and adjust before moving up to sach temps.

interesting - makes sense - just not a good tradeoff for my setup since ramping up 55-60df on a HERMs would take about 40 min - not worth it considering how 'in the ballpark' my pH usually is to what brunwater predicts.  if its way off, i'll try to adjust but knowing that its not perfect given that conversion is mostly over by the time its taken effect, but whats more important is to know for next time.
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